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authorunknown <timour@mysql.com>2004-10-11 10:47:08 +0300
committerunknown <timour@mysql.com>2004-10-11 10:47:08 +0300
commit81f7ade6627d3ab8f5e1100a97f7a3cd7ff5bad2 (patch)
tree2d2171e514f0cdbc83a7e6963ba1e79dae224b27 /sql
parent65ed693681b17414fc001099ee734f36de847f13 (diff)
parentb0982f2182600b701b74c4dcb474dbfd4d6b45f8 (diff)
downloadmariadb-git-81f7ade6627d3ab8f5e1100a97f7a3cd7ff5bad2.tar.gz
Merge with implementation of WL#1724.
sql/ha_myisam.cc: Auto merged sql/handler.cc: Auto merged sql/item.cc: Auto merged sql/item.h: Auto merged sql/item_sum.cc: Auto merged sql/item_sum.h: Auto merged sql/key.cc: Auto merged sql/mysql_priv.h: Auto merged sql/opt_sum.cc: Auto merged sql/sql_acl.cc: Auto merged sql/sql_handler.cc: Auto merged sql/sql_insert.cc: Auto merged sql/sql_select.h: Auto merged sql/opt_range.cc: Manual merge sql/sql_select.cc: Manual merge
Diffstat (limited to 'sql')
-rw-r--r--sql/ha_myisam.cc5
-rw-r--r--sql/handler.cc3
-rw-r--r--sql/item.cc39
-rw-r--r--sql/item.h4
-rw-r--r--sql/item_sum.cc1
-rw-r--r--sql/key.cc113
-rw-r--r--sql/mysql_priv.h8
-rw-r--r--sql/opt_range.cc2319
-rw-r--r--sql/opt_range.h106
-rw-r--r--sql/opt_sum.cc2
-rw-r--r--sql/sql_acl.cc8
-rw-r--r--sql/sql_handler.cc2
-rw-r--r--sql/sql_insert.cc2
-rw-r--r--sql/sql_select.cc222
-rw-r--r--sql/sql_select.h3
15 files changed, 2613 insertions, 224 deletions
diff --git a/sql/ha_myisam.cc b/sql/ha_myisam.cc
index 7e86633da89..a738e535f14 100644
--- a/sql/ha_myisam.cc
+++ b/sql/ha_myisam.cc
@@ -1538,8 +1538,9 @@ ulonglong ha_myisam::get_auto_increment()
mi_flush_bulk_insert(file, table->next_number_index);
(void) extra(HA_EXTRA_KEYREAD);
- key_copy(key,table,table->next_number_index,
- table->next_number_key_offset);
+ key_copy(key, table->record[0],
+ table->key_info + table->next_number_index,
+ table->next_number_key_offset);
error=mi_rkey(file,table->record[1],(int) table->next_number_index,
key,table->next_number_key_offset,HA_READ_PREFIX_LAST);
if (error)
diff --git a/sql/handler.cc b/sql/handler.cc
index 5f1e36d636a..e74103489eb 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -1125,7 +1125,8 @@ ulonglong handler::get_auto_increment()
else
{
byte key[MAX_KEY_LENGTH];
- key_copy(key,table,table->next_number_index,
+ key_copy(key, table->record[0],
+ table->key_info + table->next_number_index,
table->next_number_key_offset);
error=index_read(table->record[1], key, table->next_number_key_offset,
HA_READ_PREFIX_LAST);
diff --git a/sql/item.cc b/sql/item.cc
index 267560b0709..1aa07fb2b72 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -170,6 +170,45 @@ bool Item_ident::remove_dependence_processor(byte * arg)
}
+/*
+ Store the pointer to this item field into a list if not already there.
+
+ SYNOPSIS
+ Item_field::collect_item_field_processor()
+ arg pointer to a List<Item_field>
+
+ DESCRIPTION
+ The method is used by Item::walk to collect all unique Item_field objects
+ from a tree of Items into a set of items represented as a list.
+
+ IMPLEMENTATION
+ Item_cond::walk() and Item_func::walk() stop the evaluation of the
+ processor function for its arguments once the processor returns
+ true.Therefore in order to force this method being called for all item
+ arguments in a condition the method must return false.
+
+ RETURN
+ false to force the evaluation of collect_item_field_processor
+ for the subsequent items.
+*/
+
+bool Item_field::collect_item_field_processor(byte *arg)
+{
+ DBUG_ENTER("Item_field::collect_item_field_processor");
+ DBUG_PRINT("info", ("%s", field->field_name ? field->field_name : "noname"));
+ List<Item_field> *item_list= (List<Item_field>*) arg;
+ List_iterator<Item_field> item_list_it(*item_list);
+ Item_field *curr_item;
+ while ((curr_item= item_list_it++))
+ {
+ if (curr_item->eq(this, 1))
+ DBUG_RETURN(false); /* Already in the set. */
+ }
+ item_list->push_back(this);
+ DBUG_RETURN(false);
+}
+
+
bool Item::check_cols(uint c)
{
if (c != 1)
diff --git a/sql/item.h b/sql/item.h
index 71db03ad687..57322146d27 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -263,6 +263,7 @@ public:
virtual bool remove_dependence_processor(byte * arg) { return 0; }
virtual bool remove_fixed(byte * arg) { fixed= 0; return 0; }
+ virtual bool collect_item_field_processor(byte * arg) { return 0; }
virtual Item *this_item() { return this; } /* For SPs mostly. */
virtual Item *this_const_item() const { return const_cast<Item*>(this); } /* For SPs mostly. */
@@ -497,6 +498,7 @@ public:
bool get_time(TIME *ltime);
bool is_null() { return field->is_null(); }
Item *get_tmp_table_item(THD *thd);
+ bool collect_item_field_processor(byte * arg);
void cleanup();
inline uint32 max_disp_length() { return field->max_length(); }
Item_field *filed_for_view_update() { return this; }
@@ -988,6 +990,8 @@ public:
(*ref)->save_in_field(result_field, no_conversions);
}
Item *real_item() { return *ref; }
+ bool walk(Item_processor processor, byte *arg)
+ { return (*ref)->walk(processor, arg); }
void print(String *str);
void cleanup();
};
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index d400c198828..85e27991ac6 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -182,6 +182,7 @@ bool Item_sum::walk (Item_processor processor, byte *argument)
return (this->*processor)(argument);
}
+
String *
Item_sum_num::val_str(String *str)
{
diff --git a/sql/key.cc b/sql/key.cc
index b1f4c9533a9..15d84b73beb 100644
--- a/sql/key.cc
+++ b/sql/key.cc
@@ -66,94 +66,121 @@ int find_ref_key(TABLE *table,Field *field, uint *key_length)
}
- /* Copy a key from record to some buffer */
- /* if length == 0 then copy whole key */
+/*
+ Copy part of a record that forms a key or key prefix to a buffer.
+
+ SYNOPSIS
+ key_copy()
+ to_key buffer that will be used as a key
+ from_record full record to be copied from
+ key_info descriptor of the index
+ key_length specifies length of all keyparts that will be copied
+
+ DESCRIPTION
+ The function takes a complete table record (as e.g. retrieved by
+ handler::index_read()), and a description of an index on the same table,
+ and extracts the first key_length bytes of the record which are part of a
+ key into to_key. If length == 0 then copy all bytes from the record that
+ form a key.
+
+ RETURN
+ None
+*/
-void key_copy(byte *key,TABLE *table,uint idx,uint key_length)
+void key_copy(byte *to_key, byte *from_record, KEY *key_info, uint key_length)
{
uint length;
- KEY *key_info=table->key_info+idx;
KEY_PART_INFO *key_part;
if (key_length == 0)
- key_length=key_info->key_length;
- for (key_part=key_info->key_part;
- (int) key_length > 0 ;
- key_part++)
+ key_length= key_info->key_length;
+ for (key_part= key_info->key_part; (int) key_length > 0; key_part++)
{
if (key_part->null_bit)
{
- *key++= test(table->record[0][key_part->null_offset] &
+ *to_key++= test(from_record[key_part->null_offset] &
key_part->null_bit);
key_length--;
}
if (key_part->key_part_flag & HA_BLOB_PART)
{
char *pos;
- ulong blob_length=((Field_blob*) key_part->field)->get_length();
- key_length-=2;
+ ulong blob_length= ((Field_blob*) key_part->field)->get_length();
+ key_length-= 2;
((Field_blob*) key_part->field)->get_ptr(&pos);
- length=min(key_length,key_part->length);
- set_if_smaller(blob_length,length);
- int2store(key,(uint) blob_length);
- key+=2; // Skip length info
- memcpy(key,pos,blob_length);
+ length=min(key_length, key_part->length);
+ set_if_smaller(blob_length, length);
+ int2store(to_key, (uint) blob_length);
+ to_key+= 2; // Skip length info
+ memcpy(to_key, pos, blob_length);
}
else
{
- length=min(key_length,key_part->length);
- memcpy(key,table->record[0]+key_part->offset,(size_t) length);
+ length= min(key_length, key_part->length);
+ memcpy(to_key, from_record + key_part->offset, (size_t) length);
}
- key+=length;
- key_length-=length;
+ to_key+= length;
+ key_length-= length;
}
-} /* key_copy */
+}
- /* restore a key from some buffer to record */
+/*
+ Restore a key from some buffer to record.
+
+ SYNOPSIS
+ key_restore()
+ to_record record buffer where the key will be restored to
+ from_key buffer that contains a key
+ key_info descriptor of the index
+ key_length specifies length of all keyparts that will be restored
+
+ DESCRIPTION
+ This function converts a key into record format. It can be used in cases
+ when we want to return a key as a result row.
+
+ RETURN
+ None
+*/
-void key_restore(TABLE *table,byte *key,uint idx,uint key_length)
+void key_restore(byte *to_record, byte *from_key, KEY *key_info,
+ uint key_length)
{
uint length;
- KEY *key_info=table->key_info+idx;
KEY_PART_INFO *key_part;
if (key_length == 0)
{
- if (idx == (uint) -1)
- return;
- key_length=key_info->key_length;
+ key_length= key_info->key_length;
}
- for (key_part=key_info->key_part;
- (int) key_length > 0 ;
- key_part++)
+ for (key_part= key_info->key_part ; (int) key_length > 0 ; key_part++)
{
if (key_part->null_bit)
{
- if (*key++)
- table->record[0][key_part->null_offset]|= key_part->null_bit;
+ if (*from_key++)
+ to_record[key_part->null_offset]|= key_part->null_bit;
else
- table->record[0][key_part->null_offset]&= ~key_part->null_bit;
+ to_record[key_part->null_offset]&= ~key_part->null_bit;
key_length--;
}
if (key_part->key_part_flag & HA_BLOB_PART)
{
- uint blob_length=uint2korr(key);
- key+=2;
- key_length-=2;
+ uint blob_length= uint2korr(from_key);
+ from_key+= 2;
+ key_length-= 2;
((Field_blob*) key_part->field)->set_ptr((ulong) blob_length,
- (char*) key);
- length=key_part->length;
+ (char*) from_key);
+ length= key_part->length;
}
else
{
- length=min(key_length,key_part->length);
- memcpy(table->record[0]+key_part->offset,key,(size_t) length);
+ length= min(key_length, key_part->length);
+ memcpy(to_record + key_part->offset, from_key, (size_t) length);
}
- key+=length;
- key_length-=length;
+ from_key+= length;
+ key_length-= length;
}
-} /* key_restore */
+}
/*
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index b4fba907fbf..a10722cd726 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -763,7 +763,8 @@ bool add_proc_to_list(THD *thd, Item *item);
TABLE *unlink_open_table(THD *thd,TABLE *list,TABLE *find);
SQL_SELECT *make_select(TABLE *head, table_map const_tables,
- table_map read_tables, COND *conds, int *error);
+ table_map read_tables, COND *conds, int *error,
+ bool allow_null_cond= false);
enum find_item_error_report_type {REPORT_ALL_ERRORS, REPORT_EXCEPT_NOT_FOUND,
IGNORE_ERRORS};
extern const Item **not_found_item;
@@ -861,8 +862,9 @@ void print_plan(JOIN* join, double read_time, double record_count,
void mysql_print_status(THD *thd);
/* key.cc */
int find_ref_key(TABLE *form,Field *field, uint *offset);
-void key_copy(byte *key,TABLE *form,uint index,uint key_length);
-void key_restore(TABLE *form,byte *key,uint index,uint key_length);
+void key_copy(byte *to_key, byte *from_record, KEY *key_info, uint key_length);
+void key_restore(byte *to_record, byte *from_key, KEY *key_info,
+ uint key_length);
bool key_cmp_if_same(TABLE *form,const byte *key,uint index,uint key_length);
void key_unpack(String *to,TABLE *form,uint index);
bool check_if_key_used(TABLE *table, uint idx, List<Item> &fields);
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 303d9f3d655..acceac81b08 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -352,6 +352,7 @@ class TABLE_READ_PLAN;
class TRP_ROR_INTERSECT;
class TRP_ROR_UNION;
class TRP_ROR_INDEX_MERGE;
+ class TRP_GROUP_MIN_MAX;
struct st_ror_scan_info;
@@ -386,6 +387,8 @@ TRP_ROR_INTERSECT *get_best_covering_ror_intersect(PARAM *param,
static
TABLE_READ_PLAN *get_best_disjunct_quick(PARAM *param, SEL_IMERGE *imerge,
double read_time);
+static
+TRP_GROUP_MIN_MAX *get_best_group_min_max(PARAM *param, SEL_TREE *tree);
static int get_index_merge_params(PARAM *param, key_map& needed_reg,
SEL_IMERGE *imerge, double *read_time,
ha_rows* imerge_rows);
@@ -642,13 +645,15 @@ int imerge_list_or_tree(PARAM *param,
*/
SQL_SELECT *make_select(TABLE *head, table_map const_tables,
- table_map read_tables, COND *conds, int *error)
+ table_map read_tables, COND *conds, int *error,
+ bool allow_null_cond)
{
SQL_SELECT *select;
DBUG_ENTER("make_select");
*error=0;
- if (!conds)
+
+ if (!conds && !allow_null_cond)
DBUG_RETURN(0);
if (!(select= new SQL_SELECT))
{
@@ -778,7 +783,7 @@ QUICK_INDEX_MERGE_SELECT::QUICK_INDEX_MERGE_SELECT(THD *thd_param,
index= MAX_KEY;
head= table;
bzero(&read_record, sizeof(read_record));
- init_sql_alloc(&alloc,1024,0);
+ init_sql_alloc(&alloc, thd->variables.range_alloc_block_size, 0);
DBUG_VOID_RETURN;
}
@@ -833,7 +838,7 @@ QUICK_ROR_INTERSECT_SELECT::QUICK_ROR_INTERSECT_SELECT(THD *thd_param,
head= table;
record= head->record[0];
if (!parent_alloc)
- init_sql_alloc(&alloc,1024,0);
+ init_sql_alloc(&alloc, thd->variables.range_alloc_block_size, 0);
else
bzero(&alloc, sizeof(MEM_ROOT));
last_rowid= (byte*)alloc_root(parent_alloc? parent_alloc : &alloc,
@@ -1444,6 +1449,41 @@ public:
/*
+ Plan for a QUICK_GROUP_MIN_MAX_SELECT scan.
+*/
+
+class TRP_GROUP_MIN_MAX : public TABLE_READ_PLAN
+{
+private:
+ bool have_min, have_max;
+ KEY_PART_INFO *min_max_arg_part;
+ uint group_prefix_len;
+ uint used_key_parts;
+ uint group_key_parts;
+ KEY *index_info;
+ uint index;
+ uint key_infix_len;
+ byte key_infix[MAX_KEY_LENGTH];
+ SEL_TREE *range_tree; /* Represents all range predicates in the query. */
+ SEL_ARG *index_tree; /* The SEL_ARG sub-tree corresponding to index_info. */
+ uint param_idx; /* Index of used key in param->key. */
+ /* Number of records selected by the ranges in index_tree. */
+public:
+ ha_rows quick_prefix_records;
+public:
+ TRP_GROUP_MIN_MAX(bool have_min, bool have_max,
+ KEY_PART_INFO *min_max_arg_part, uint group_prefix_len,
+ uint used_key_parts, uint group_key_parts, KEY *index_info,
+ uint index, uint key_infix_len, byte *key_infix,
+ SEL_TREE *tree, SEL_ARG *index_tree, uint param_idx,
+ ha_rows quick_prefix_records);
+
+ QUICK_SELECT_I *make_quick(PARAM *param, bool retrieve_full_rows,
+ MEM_ROOT *parent_alloc);
+};
+
+
+/*
Fill param->needed_fields with bitmap of fields used in the query.
SYNOPSIS
fill_used_fields_bitmap()
@@ -1534,28 +1574,28 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
uint idx;
double scan_time;
DBUG_ENTER("SQL_SELECT::test_quick_select");
- //printf("\nQUERY: %s\n", thd->query);
DBUG_PRINT("enter",("keys_to_use: %lu prev_tables: %lu const_tables: %lu",
keys_to_use.to_ulonglong(), (ulong) prev_tables,
(ulong) const_tables));
delete quick;
quick=0;
- needed_reg.clear_all(); quick_keys.clear_all();
- if (!cond || (specialflag & SPECIAL_SAFE_MODE) && ! force_quick_range ||
+ needed_reg.clear_all();
+ quick_keys.clear_all();
+ if ((specialflag & SPECIAL_SAFE_MODE) && ! force_quick_range ||
!limit)
DBUG_RETURN(0); /* purecov: inspected */
if (keys_to_use.is_clear_all())
DBUG_RETURN(0);
- records=head->file->records;
+ records= head->file->records;
if (!records)
records++; /* purecov: inspected */
- scan_time=(double) records / TIME_FOR_COMPARE+1;
- read_time=(double) head->file->scan_time()+ scan_time + 1.1;
+ scan_time= (double) records / TIME_FOR_COMPARE + 1;
+ read_time= (double) head->file->scan_time() + scan_time + 1.1;
if (head->force_index)
scan_time= read_time= DBL_MAX;
if (limit < records)
- read_time=(double) records+scan_time+1; // Force to use index
+ read_time= (double) records + scan_time + 1; // Force to use index
else if (read_time <= 2.0 && !force_quick_range)
DBUG_RETURN(0); /* No need for quick select */
@@ -1565,7 +1605,7 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
if (!keys_to_use.is_clear_all())
{
MEM_ROOT *old_root,alloc;
- SEL_TREE *tree;
+ SEL_TREE *tree= NULL;
KEY_PART *key_parts;
KEY *key_info;
PARAM param;
@@ -1580,7 +1620,6 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
param.keys=0;
param.mem_root= &alloc;
param.needed_reg= &needed_reg;
-
param.imerge_cost_buff_size= 0;
thd->no_errors=1; // Don't warn about NULL
@@ -1642,95 +1681,118 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
read_time= key_read_time;
}
- if ((tree=get_mm_tree(&param,cond)))
+ TABLE_READ_PLAN *best_trp= NULL;
+ TRP_GROUP_MIN_MAX *group_trp;
+ double best_read_time= read_time;
+
+ if (cond)
+ tree= get_mm_tree(&param,cond);
+
+ if (tree && tree->type == SEL_TREE::IMPOSSIBLE)
{
- if (tree->type == SEL_TREE::IMPOSSIBLE)
- {
- records=0L; // Return -1 from this function
- read_time= (double) HA_POS_ERROR;
- }
- else if (tree->type == SEL_TREE::KEY ||
- tree->type == SEL_TREE::KEY_SMALLER)
+ records=0L; /* Return -1 from this function. */
+ read_time= (double) HA_POS_ERROR;
+ goto free_mem;
+ }
+ else if (tree && tree->type != SEL_TREE::KEY &&
+ tree->type != SEL_TREE::KEY_SMALLER)
+ goto free_mem;
+
+
+ /*
+ Try to construct a QUICK_GROUP_MIN_MAX_SELECT.
+ Notice that it can be constructed no matter if there is a range tree.
+ */
+ group_trp= get_best_group_min_max(&param, tree);
+ if (group_trp && group_trp->read_cost < best_read_time)
+ {
+ best_trp= group_trp;
+ best_read_time= best_trp->read_cost;
+ }
+
+ if (tree)
+ {/*
+ It is possible to use a range-based quick select (but it might be slower
+ than 'all' table scan).
+ */
+ if (tree->merges.is_empty())
{
- TABLE_READ_PLAN *best_trp;
+ TRP_RANGE *range_trp;
+ TRP_ROR_INTERSECT *rori_trp;
+ bool can_build_covering= FALSE;
+
+ /* Get best 'range' plan and prepare data for making other plans */
+ if ((range_trp= get_key_scans_params(&param, tree, FALSE,
+ best_read_time)))
+ {
+ best_trp= range_trp;
+ best_read_time= best_trp->read_cost;
+ }
+
/*
- It is possible to use a quick select (but maybe it would be slower
- than 'all' table scan).
+ Simultaneous key scans and row deletes on several handler
+ objects are not allowed so don't use ROR-intersection for
+ table deletes.
*/
- if (tree->merges.is_empty())
+ if ((thd->lex->sql_command != SQLCOM_DELETE) )//&&
+// (thd->lex->sql_command != SQLCOM_UPDATE))
{
- double best_read_time= read_time;
- TRP_ROR_INTERSECT *new_trp;
- bool can_build_covering= FALSE;
-
- /* Get best 'range' plan and prepare data for making other plans */
- if ((best_trp= get_key_scans_params(&param, tree, FALSE,
- best_read_time)))
- best_read_time= best_trp->read_cost;
-
/*
- Simultaneous key scans and row deletes on several handler
- objects are not allowed so don't use ROR-intersection for
- table deletes.
+ Get best non-covering ROR-intersection plan and prepare data for
+ building covering ROR-intersection.
*/
- if ((thd->lex->sql_command != SQLCOM_DELETE) )//&&
-// (thd->lex->sql_command != SQLCOM_UPDATE))
+ if ((rori_trp= get_best_ror_intersect(&param, tree, best_read_time,
+ &can_build_covering)))
{
- /*
- Get best non-covering ROR-intersection plan and prepare data for
- building covering ROR-intersection.
- */
- if ((new_trp= get_best_ror_intersect(&param, tree, best_read_time,
- &can_build_covering)))
- {
- best_trp= new_trp;
- best_read_time= best_trp->read_cost;
- }
-
+ best_trp= rori_trp;
+ best_read_time= best_trp->read_cost;
/*
Try constructing covering ROR-intersect only if it looks possible
and worth doing.
*/
- if (new_trp && !new_trp->is_covering && can_build_covering &&
- (new_trp= get_best_covering_ror_intersect(&param, tree,
- best_read_time)))
- best_trp= new_trp;
+ if (!rori_trp->is_covering && can_build_covering &&
+ (rori_trp= get_best_covering_ror_intersect(&param, tree,
+ best_read_time)))
+ best_trp= rori_trp;
}
}
- else
+ }
+ else
+ {
+ /* Try creating index_merge/ROR-union scan. */
+ SEL_IMERGE *imerge;
+ TABLE_READ_PLAN *best_conj_trp= NULL, *new_conj_trp;
+ LINT_INIT(new_conj_trp); /* no empty index_merge lists possible */
+
+ DBUG_PRINT("info",("No range reads possible,"
+ " trying to construct index_merge"));
+ List_iterator_fast<SEL_IMERGE> it(tree->merges);
+ while ((imerge= it++))
{
- /* Try creating index_merge/ROR-union scan. */
- SEL_IMERGE *imerge;
- TABLE_READ_PLAN *best_conj_trp= NULL, *new_conj_trp;
- LINT_INIT(new_conj_trp); /* no empty index_merge lists possible */
-
-
- DBUG_PRINT("info",("No range reads possible,"
- " trying to construct index_merge"));
- List_iterator_fast<SEL_IMERGE> it(tree->merges);
- while ((imerge= it++))
- {
- new_conj_trp= get_best_disjunct_quick(&param, imerge, read_time);
- if (!best_conj_trp || (new_conj_trp && new_conj_trp->read_cost <
- best_conj_trp->read_cost))
- best_conj_trp= new_conj_trp;
- }
- best_trp= best_conj_trp;
+ new_conj_trp= get_best_disjunct_quick(&param, imerge, best_read_time);
+ if (!best_conj_trp || (new_conj_trp && new_conj_trp->read_cost <
+ best_conj_trp->read_cost))
+ best_conj_trp= new_conj_trp;
}
- my_pthread_setspecific_ptr(THR_MALLOC, old_root);
+ if (best_conj_trp)
+ best_trp= best_conj_trp;
+ }
+ }
- /* If we got a read plan, create a quick select from it. */
- if (best_trp)
- {
- records= best_trp->records;
- if (!(quick= best_trp->make_quick(&param, TRUE)) || quick->init())
- {
- delete quick;
- quick= NULL;
- }
- }
+ my_pthread_setspecific_ptr(THR_MALLOC, old_root);
+
+ /* If we got a read plan, create a quick select from it. */
+ if (best_trp)
+ {
+ records= best_trp->records;
+ if (!(quick= best_trp->make_quick(&param, TRUE)) || quick->init())
+ {
+ delete quick;
+ quick= NULL;
}
}
+
+ free_mem:
my_pthread_setspecific_ptr(THR_MALLOC, old_root);
free_root(&alloc,MYF(0)); // Return memory & allocator
thd->no_errors=0;
@@ -2111,7 +2173,10 @@ skip_to_ror_scan:
NOTES
It is assumed that we will read trough the whole key range and that all
- key blocks are half full (normally things are much better).
+ key blocks are half full (normally things are much better). It is also
+ assumed that each time we read the next key from the index, the handler
+ performs a random seek, thus the cost is proportional to the number of
+ blocks read.
TODO:
Move this to handler->read_time() by adding a flag 'index-only-read' to
@@ -2756,7 +2821,7 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
intersect_scans_end= intersect_scans;
ror_intersect_reinit(intersect);
if (!ror_intersect_add(param, intersect, *cur_ror_scan))
- DBUG_RETURN(NULL); /* shouldn't happen actually actually */
+ DBUG_RETURN(NULL); /* shouldn't happen actually */
*(intersect_scans_end++)= *cur_ror_scan;
best_num++;
}
@@ -2790,6 +2855,9 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
trp->index_scan_costs= best_index_scan_costs;
trp->cpk_scan= cpk_scan;
}
+ DBUG_PRINT("info",
+ ("Returning non-covering ROR-intersect plan: cost %g, records %lu",
+ trp->read_cost, (ulong) trp->records));
DBUG_RETURN(trp);
}
@@ -2932,6 +3000,9 @@ TRP_ROR_INTERSECT *get_best_covering_ror_intersect(PARAM *param,
trp->read_cost= total_cost;
trp->records= records;
+ DBUG_PRINT("info",
+ ("Returning covering ROR-intersect plan: cost %g, records %lu",
+ trp->read_cost, (ulong) trp->records));
DBUG_RETURN(trp);
}
@@ -2993,29 +3064,28 @@ static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
tree->n_ror_scans++;
tree->ror_scans_map.set_bit(idx);
}
+ double cpu_cost= (double) found_records / TIME_FOR_COMPARE;
if (found_records != HA_POS_ERROR && found_records > 2 &&
read_index_only &&
(param->table->file->index_flags(keynr, param->max_key_part,1) &
HA_KEYREAD_ONLY) &&
!(pk_is_clustered && keynr == param->table->primary_key))
- {
/* We can resolve this by only reading through this key. */
- found_read_time= (get_index_only_read_time(param,found_records,keynr)+
- (double) found_records / TIME_FOR_COMPARE);
- }
+ found_read_time= get_index_only_read_time(param,found_records,keynr) +
+ cpu_cost;
else
- {
/*
cost(read_through_index) = cost(disk_io) + cost(row_in_range_checks)
The row_in_range check is in QUICK_RANGE_SELECT::cmp_next function.
*/
- found_read_time= (param->table->file->read_time(keynr,
- param->range_count,
- found_records)+
- (double) found_records / TIME_FOR_COMPARE);
- }
+ found_read_time= param->table->file->read_time(keynr,
+ param->range_count,
+ found_records) +
+ cpu_cost;
+
DBUG_PRINT("info",("read_time: %g found_read_time: %g",
read_time, found_read_time));
+
if (read_time > found_read_time && found_records != HA_POS_ERROR
/*|| read_time == DBL_MAX*/ )
{
@@ -3037,9 +3107,10 @@ static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
read_plan->records= best_records;
read_plan->is_ror= tree->ror_scans_map.is_set(idx);
read_plan->read_cost= read_time;
- DBUG_PRINT("info",("Returning range plan for key %s, cost %g",
- param->table->key_info[param->real_keynr[idx]].name,
- read_plan->read_cost));
+ DBUG_PRINT("info",
+ ("Returning range plan for key %s, cost %g, records %lu",
+ param->table->key_info[param->real_keynr[idx]].name,
+ read_plan->read_cost, (ulong) read_plan->records));
}
}
else
@@ -3923,6 +3994,13 @@ key_and(SEL_ARG *key1,SEL_ARG *key2,uint clone_flag)
return 0; // Can't optimize this
}
+ if ((key1->min_flag | key2->min_flag) & GEOM_FLAG)
+ {
+ key1->free_tree();
+ key2->free_tree();
+ return 0; // Can't optimize this
+ }
+
key1->use_count--;
key2->use_count--;
SEL_ARG *e1=key1->first(), *e2=key2->first(), *new_tree=0;
@@ -5029,16 +5107,15 @@ static bool is_key_scan_ror(PARAM *param, uint keynr, uint8 nparts)
key_tree SEL_ARG tree for the used key
parent_alloc If not NULL, use it to allocate memory for
quick select data. Otherwise use quick->alloc.
-
- RETURN
- NULL on error
- otherwise created quick select
-
NOTES
- The caller must call QUICK_SELCT::init for returned quick select
+ The caller must call QUICK_SELECT::init for returned quick select
CAUTION! This function may change THR_MALLOC to a MEM_ROOT which will be
deallocated when the returned quick select is deleted.
+
+ RETURN
+ NULL on error
+ otherwise created quick select
*/
QUICK_RANGE_SELECT *
@@ -5681,6 +5758,90 @@ int QUICK_RANGE_SELECT::get_next()
}
+/*
+ Get the next record with a different prefix.
+
+ SYNOPSIS
+ QUICK_RANGE_SELECT::get_next_prefix()
+ prefix_length length of cur_prefix
+ cur_prefix prefix of a key to be searached for
+
+ DESCRIPTION
+ Each subsequent call to the method retrieves the first record that has a
+ prefix with length prefix_length different from cur_prefix, such that the
+ record with the new prefix is within the ranges described by
+ this->ranges. The record found is stored into the buffer pointed by
+ this->record.
+ The method is useful for GROUP-BY queries with range conditions to
+ discover the prefix of the next group that satisfies the range conditions.
+
+ TODO
+ This method is a modified copy of QUICK_RANGE_SELECT::get_next(), so both
+ methods should be unified into a more general one to reduce code
+ duplication.
+
+ RETURN
+ 0 on success
+ HA_ERR_END_OF_FILE if returned all keys
+ other if some error occurred
+*/
+
+int QUICK_RANGE_SELECT::get_next_prefix(uint prefix_length, byte *cur_prefix)
+{
+ DBUG_ENTER("QUICK_RANGE_SELECT::get_next_prefix");
+
+ for (;;)
+ {
+ int result;
+ key_range start_key, end_key;
+ if (range)
+ {
+ /* Read the next record in the same range with prefix after cur_prefix. */
+ DBUG_ASSERT(cur_prefix);
+ result= file->index_read(record, cur_prefix, prefix_length,
+ HA_READ_AFTER_KEY);
+ if (result || (file->compare_key(file->end_range) <= 0))
+ DBUG_RETURN(result);
+ }
+
+ if (!cur_range)
+ range= *(cur_range= (QUICK_RANGE**) ranges.buffer); /* First range. */
+ else
+ range=
+ (cur_range == ((QUICK_RANGE**) ranges.buffer + ranges.elements - 1)) ?
+ (QUICK_RANGE*) 0 : *(++cur_range); /* Next range. */
+
+ if (!range)
+ DBUG_RETURN(HA_ERR_END_OF_FILE); // All ranges used
+
+ start_key.key= (const byte*) range->min_key;
+ start_key.length= min(range->min_length, prefix_length);
+ start_key.flag= ((range->flag & NEAR_MIN) ? HA_READ_AFTER_KEY :
+ (range->flag & EQ_RANGE) ?
+ HA_READ_KEY_EXACT : HA_READ_KEY_OR_NEXT);
+ end_key.key= (const byte*) range->max_key;
+ end_key.length= min(range->max_length, prefix_length);
+ /*
+ We use READ_AFTER_KEY here because if we are reading on a key
+ prefix we want to find all keys with this prefix
+ */
+ end_key.flag= (range->flag & NEAR_MAX ? HA_READ_BEFORE_KEY :
+ HA_READ_AFTER_KEY);
+
+ result= file->read_range_first(range->min_length ? &start_key : 0,
+ range->max_length ? &end_key : 0,
+ test(range->flag & EQ_RANGE),
+ sorted);
+ if (range->flag == (UNIQUE_RANGE | EQ_RANGE))
+ range=0; // Stop searching
+
+ if (result != HA_ERR_END_OF_FILE)
+ DBUG_RETURN(result);
+ range=0; // No matching rows; go to next range
+ }
+}
+
+
/* Get next for geometrical indexes */
int QUICK_RANGE_SELECT_GEOM::get_next()
@@ -6218,6 +6379,1954 @@ static void print_ror_scans_arr(TABLE *table, const char *msg,
DBUG_VOID_RETURN;
}
+
+/*******************************************************************************
+* Implementation of QUICK_GROUP_MIN_MAX_SELECT
+*******************************************************************************/
+
+static inline uint get_field_keypart(KEY *index, Field *field);
+static inline SEL_ARG * get_index_range_tree(uint index, SEL_TREE* range_tree,
+ PARAM *param, uint *param_idx);
+static bool
+get_constant_key_infix(KEY *index_info, SEL_ARG *index_range_tree,
+ KEY_PART_INFO *first_non_group_part,
+ KEY_PART_INFO *min_max_arg_part,
+ KEY_PART_INFO *last_part, THD *thd,
+ byte *key_infix, uint *key_infix_len,
+ KEY_PART_INFO **first_non_infix_part);
+static bool
+check_group_min_max_predicates(COND *cond, Item_field *min_max_arg_item,
+ Field::imagetype image_type);
+
+static void
+cost_group_min_max(TABLE* table, KEY *index_info, uint used_key_parts,
+ uint group_key_parts, SEL_TREE *range_tree,
+ SEL_ARG *index_tree, ha_rows quick_prefix_records,
+ bool have_min, bool have_max,
+ double *read_cost, ha_rows *records);
+
+/*
+ Test if this access method is applicable to a GROUP query with MIN/MAX
+ functions, and if so, construct a new TRP object.
+
+ SYNOPSIS
+ get_best_group_min_max()
+ param Parameter from test_quick_select
+ sel_tree Range tree generated by get_mm_tree
+
+ DESCRIPTION
+ Test whether a query can be computed via a QUICK_GROUP_MIN_MAX_SELECT.
+ Queries computable via a QUICK_GROUP_MIN_MAX_SELECT must satisfy the
+ following conditions:
+ A) Table T has at least one compound index I of the form:
+ I = <A_1, ...,A_k, [B_1,..., B_m], C, [D_1,...,D_n]>
+ B) Query conditions:
+ B0. Q is over a single table T.
+ B1. The attributes referenced by Q are a subset of the attributes of I.
+ B2. All attributes QA in Q can be divided into 3 overlapping groups:
+ - SA = {S_1, ..., S_l, [C]} - from the SELECT clause, where C is
+ referenced by any number of MIN and/or MAX functions if present.
+ - WA = {W_1, ..., W_p} - from the WHERE clause
+ - GA = <G_1, ..., G_k> - from the GROUP BY clause (if any)
+ = SA - if Q is a DISTINCT query (based on the
+ equivalence of DISTINCT and GROUP queries.
+ - NGA = QA - (GA union C) = {NG_1, ..., NG_m} - the ones not in GROUP BY
+ and not referenced by MIN/MAX functions.
+ with the following properties specified below.
+
+ SA1. There is at most one attribute in SA referenced by any number of
+ MIN and/or MAX functions which, which if present, is denoted as C.
+ SA2. The position of the C attribute in the index is after the last A_k.
+ SA3. The attribute C can be referenced in the WHERE clause only in
+ predicates of the forms:
+ - (C {< | <= | > | >= | =} const)
+ - (const {< | <= | > | >= | =} C)
+ - (C between const_i and const_j)
+ - C IS NULL
+ - C IS NOT NULL
+ - C != const
+ SA4. If Q has a GROUP BY clause, there are no other aggregate functions
+ except MIN and MAX. For queries with DISTINCT, aggregate functions
+ are allowed.
+ SA5. The select list in DISTINCT queries should not contain expressions.
+ GA1. If Q has a GROUP BY clause, then GA is a prefix of I. That is, if
+ G_i = A_j => i = j.
+ GA2. If Q has a DISTINCT clause, then there is a permutation of SA that
+ forms a prefix of I. This permutation is used as the GROUP clause
+ when the DISTINCT query is converted to a GROUP query.
+ GA3. The attributes in GA may participate in arbitrary predicates, divided
+ into two groups:
+ - RNG(G_1,...,G_q ; where q <= k) is a range condition over the
+ attributes of a prefix of GA
+ - PA(G_i1,...G_iq) is an arbitrary predicate over an arbitrary subset
+ of GA. Since P is applied to only GROUP attributes it filters some
+ groups, and thus can be applied after the grouping.
+ GA4. There are no expressions among G_i, just direct column references.
+ NGA1.If in the index I there is a gap between the last GROUP attribute G_k,
+ and the MIN/MAX attribute C, then NGA must consist of exactly the index
+ attributes that constitute the gap. As a result there is a permutation
+ of NGA that coincides with the gap in the index <B_1, ..., B_m>.
+ NGA2.If BA <> {}, then the WHERE clause must contain a conjunction EQ of
+ equality conditions for all NG_i of the form (NG_i = const) or
+ (const = NG_i), such that each NG_i is referenced in exactly one
+ conjunct. Informally, the predicates provide constants to fill the
+ gap in the index.
+ WA1. There are no other attributes in the WHERE clause except the ones
+ referenced in predicates RNG, PA, PC, EQ defined above. Therefore
+ WA is subset of (GA union NGA union C) for GA,NGA,C that pass the above
+ tests. By transitivity then it also follows that each WA_i participates
+ in the index I (if this was already tested for GA, NGA and C).
+
+ C) Overall query form:
+ SELECT EXPR([A_1,...,A_k], [B_1,...,B_m], [MIN(C)], [MAX(C)])
+ FROM T
+ WHERE [RNG(A_1,...,A_p ; where p <= k)]
+ [AND EQ(B_1,...,B_m)]
+ [AND PC(C)]
+ [AND PA(A_i1,...,A_iq)]
+ GROUP BY A_1,...,A_k
+ [HAVING PH(A_1, ..., B_1,..., C)]
+ where EXPR(...) is an arbitrary expression over some or all SELECT fields,
+ or:
+ SELECT DISTINCT A_i1,...,A_ik
+ FROM T
+ WHERE [RNG(A_1,...,A_p ; where p <= k)]
+ [AND PA(A_i1,...,A_iq)];
+
+ NOTES
+ If the current query satisfies the conditions above, and if
+ (mem_root! = NULL), then the function constructs and returns a new TRP
+ object, that is later used to construct a new QUICK_GROUP_MIN_MAX_SELECT.
+ If (mem_root == NULL), then the function only tests whether the current
+ query satisfies the conditions above, and, if so, sets
+ is_applicable = TRUE.
+
+ Queries with DISTINCT for which index access can be used are transformed
+ into equivalent group-by queries of the form:
+
+ SELECT A_1,...,A_k FROM T
+ WHERE [RNG(A_1,...,A_p ; where p <= k)]
+ [AND PA(A_i1,...,A_iq)]
+ GROUP BY A_1,...,A_k;
+
+ The group-by list is a permutation of the select attributes, according
+ to their order in the index.
+
+ TODO
+ - What happens if the query groups by the MIN/MAX field, and there is no
+ other field as in: "select min(a) from t1 group by a" ?
+ - We assume that the general correctness of the GROUP-BY query was checked
+ before this point. Is this correct, or do we have to check it completely?
+
+ RETURN
+ If mem_root != NULL
+ - valid TRP_GROUP_MIN_MAX object if this QUICK class can be used for
+ the query
+ - NULL o/w.
+ If mem_root == NULL
+ - NULL
+*/
+
+static TRP_GROUP_MIN_MAX *
+get_best_group_min_max(PARAM *param, SEL_TREE *tree)
+{
+ THD *thd= param->thd;
+ JOIN *join= thd->lex->select_lex.join;
+ TABLE *table= param->table;
+ bool have_min= FALSE; /* TRUE if there is a MIN function. */
+ bool have_max= FALSE; /* TRUE if there is a MAX function. */
+ Item_field *min_max_arg_item= NULL;/* The argument of all MIN/MAX functions.*/
+ KEY_PART_INFO *min_max_arg_part= NULL; /* The corresponding keypart. */
+ uint group_prefix_len= 0; /* Length (in bytes) of the key prefix. */
+ KEY *index_info= NULL; /* The index chosen for data access. */
+ uint index= 0; /* The id of the chosen index. */
+ uint group_key_parts= 0; /* Number of index key parts in the group prefix. */
+ uint used_key_parts= 0; /* Number of index key parts used for access. */
+ byte key_infix[MAX_KEY_LENGTH]; /* Constants from equality predicates.*/
+ uint key_infix_len= 0; /* Length of key_infix. */
+ TRP_GROUP_MIN_MAX *read_plan= NULL; /* The eventually constructed TRP. */
+ uint key_part_nr;
+ ORDER *tmp_group;
+ Item *item;
+ Item_field *item_field;
+
+ DBUG_ENTER("get_best_group_min_max");
+
+ /* Perform few 'cheap' tests whether this access method is applicable. */
+ if (!join || (thd->lex->sql_command != SQLCOM_SELECT))
+ DBUG_RETURN(NULL); /* This is not a select statement. */
+ if ((join->tables != 1) || /* The query must reference one table. */
+ ((!join->group_list) && /* Neither GROUP BY nor a DISTINCT query. */
+ (!join->select_distinct)))
+ DBUG_RETURN(NULL);
+ if(table->keys == 0) /* There are no indexes to use. */
+ DBUG_RETURN(NULL);
+
+ /* Analyze the query in more detail. */
+ List_iterator<Item> select_items_it(join->fields_list);
+
+ /* Check (SA1,SA4) and store the only MIN/MAX argument - the C attribute.*/
+ if(join->make_sum_func_list(join->all_fields, join->fields_list, 1))
+ DBUG_RETURN(NULL);
+ if (join->sum_funcs[0])
+ {
+ Item_sum *min_max_item;
+ Item_sum **func_ptr= join->sum_funcs;
+ while ((min_max_item= *(func_ptr++)))
+ {
+ if (min_max_item->sum_func() == Item_sum::MIN_FUNC)
+ have_min= TRUE;
+ else if (min_max_item->sum_func() == Item_sum::MAX_FUNC)
+ have_max= TRUE;
+ else
+ DBUG_RETURN(NULL);
+
+ Item *expr= min_max_item->args[0]; /* The argument of MIN/MAX. */
+ if (expr->type() == Item::FIELD_ITEM) /* Is it an attribute? */
+ {
+ if (! min_max_arg_item)
+ min_max_arg_item= (Item_field*) expr;
+ else if (! min_max_arg_item->eq(expr, 1))
+ DBUG_RETURN(NULL);
+ }
+ else
+ DBUG_RETURN(NULL);
+ }
+ }
+
+ /* Check (SA5). */
+ if (join->select_distinct)
+ {
+ while ((item= select_items_it++))
+ {
+ if (item->type() != Item::FIELD_ITEM)
+ DBUG_RETURN(NULL);
+ }
+ }
+
+ /* Check (GA4) - that there are no expressions among the group attributes. */
+ for (tmp_group= join->group_list; tmp_group; tmp_group= tmp_group->next)
+ {
+ if ((*tmp_group->item)->type() != Item::FIELD_ITEM)
+ DBUG_RETURN(NULL);
+ }
+
+ /*
+ Check that table has at least one compound index such that the conditions
+ (GA1,GA2) are all TRUE. If there is more than one such index, select the
+ first one. Here we set the variables: group_prefix_len and index_info.
+ */
+ KEY *cur_index_info= table->key_info;
+ KEY *cur_index_info_end= cur_index_info + table->keys;
+ KEY_PART_INFO *cur_part= NULL;
+ KEY_PART_INFO *end_part; /* Last part for loops. */
+ /* Last index part. */
+ KEY_PART_INFO *last_part= NULL;
+ KEY_PART_INFO *first_non_group_part= NULL;
+ KEY_PART_INFO *first_non_infix_part= NULL;
+ uint key_infix_parts= 0;
+ uint cur_group_key_parts= 0;
+ uint cur_group_prefix_len= 0;
+ /* Cost-related variables for the best index so far. */
+ double best_read_cost= DBL_MAX;
+ ha_rows best_records= 0;
+ SEL_ARG *best_index_tree= NULL;
+ ha_rows best_quick_prefix_records= 0;
+ uint best_param_idx= 0;
+ double cur_read_cost= DBL_MAX;
+ ha_rows cur_records;
+ SEL_ARG *cur_index_tree= NULL;
+ ha_rows cur_quick_prefix_records= 0;
+ uint cur_param_idx;
+
+ for (uint cur_index= 0 ; cur_index_info != cur_index_info_end ;
+ cur_index_info++, cur_index++)
+ {
+ /* Check (B1) - if current index is covering. */
+ if (!table->used_keys.is_set(cur_index))
+ goto next_index;
+
+ /*
+ Check (GA1) for GROUP BY queries.
+ */
+ if (join->group_list)
+ {
+ cur_part= cur_index_info->key_part;
+ end_part= cur_part + cur_index_info->key_parts;
+ /* Iterate in parallel over the GROUP list and the index parts. */
+ for (tmp_group= join->group_list; tmp_group && (cur_part != end_part);
+ tmp_group= tmp_group->next, cur_part++)
+ {
+ /*
+ TODO:
+ tmp_group::item is an array of Item, is it OK to consider only the
+ first Item? If so, then why? What is the array for?
+ */
+ /* Above we already checked that all group items are fields. */
+ DBUG_ASSERT((*tmp_group->item)->type() == Item::FIELD_ITEM);
+ Item_field *group_field= (Item_field *) (*tmp_group->item);
+ if (group_field->field->eq(cur_part->field))
+ {
+ cur_group_prefix_len+= cur_part->store_length;
+ ++cur_group_key_parts;
+ }
+ else
+ goto next_index;
+ }
+ }
+ /*
+ Check (GA2) if this is a DISTINCT query.
+ If GA2, then Store a new ORDER object in group_fields_array at the
+ position of the key part of item_field->field. Thus we get the ORDER
+ objects for each field ordered as the corresponding key parts.
+ Later group_fields_array of ORDER objects is used to convert the query
+ to a GROUP query.
+ */
+ else if (join->select_distinct)
+ {
+ select_items_it.rewind();
+ while ((item= select_items_it++))
+ {
+ item_field= (Item_field*) item; /* (SA5) already checked above. */
+ /* Find the order of the key part in the index. */
+ key_part_nr= get_field_keypart(cur_index_info, item_field->field);
+ if (key_part_nr < 1 || key_part_nr > join->fields_list.elements)
+ goto next_index;
+ cur_part= cur_index_info->key_part + key_part_nr - 1;
+ cur_group_prefix_len+= cur_part->store_length;
+ }
+ cur_group_key_parts= join->fields_list.elements;
+ }
+ else
+ DBUG_ASSERT(FALSE);
+
+ /* Check (SA2). */
+ if (min_max_arg_item)
+ {
+ key_part_nr= get_field_keypart(cur_index_info, min_max_arg_item->field);
+ if (key_part_nr <= cur_group_key_parts)
+ goto next_index;
+ min_max_arg_part= cur_index_info->key_part + key_part_nr - 1;
+ }
+
+ /*
+ Check (NGA1, NGA2) and extract a sequence of constants to be used as part
+ of all search keys.
+ */
+
+ /*
+ If there is MIN/MAX, each keypart between the last group part and the
+ MIN/MAX part must participate in one equality with constants, and all
+ keyparts after the MIN/MAX part must not be referenced in the query.
+
+ If there is no MIN/MAX, the keyparts after the last group part can be
+ referenced only in equalities with constants, and the referenced keyparts
+ must form a sequence without any gaps that starts immediately after the
+ last group keypart.
+ */
+ last_part= cur_index_info->key_part + cur_index_info->key_parts;
+ first_non_group_part= (cur_group_key_parts < cur_index_info->key_parts) ?
+ cur_index_info->key_part + cur_group_key_parts :
+ NULL;
+ first_non_infix_part= min_max_arg_part ?
+ (min_max_arg_part < last_part) ?
+ min_max_arg_part + 1 :
+ NULL :
+ NULL;
+ if (first_non_group_part &&
+ (!min_max_arg_part || (min_max_arg_part - first_non_group_part > 0)))
+ {
+ if (tree)
+ {
+ uint dummy;
+ SEL_ARG *index_range_tree= get_index_range_tree(cur_index, tree, param,
+ &dummy);
+ if (!get_constant_key_infix(cur_index_info, index_range_tree,
+ first_non_group_part, min_max_arg_part,
+ last_part, thd, key_infix, &key_infix_len,
+ &first_non_infix_part))
+ goto next_index;
+ }
+ else if (min_max_arg_part &&
+ (min_max_arg_part - first_non_group_part > 0))
+ /*
+ There is a gap but no range tree, thus no predicates at all for the
+ non-group keyparts.
+ */
+ goto next_index;
+ }
+
+ /*
+ Test (WA1) partially - that no other keypart after the last infix part is
+ referenced in the query.
+ */
+ if (first_non_infix_part)
+ {
+ for (cur_part= first_non_infix_part; cur_part != last_part; cur_part++)
+ {
+ if (cur_part->field->query_id == thd->query_id)
+ goto next_index;
+ }
+ }
+
+ /* If we got to this point, cur_index_info passes the test. */
+ key_infix_parts= key_infix_len ?
+ (first_non_infix_part - first_non_group_part) : 0;
+ used_key_parts= cur_group_key_parts + key_infix_parts;
+
+ /* Compute the cost of using this index. */
+ if (tree)
+ {
+ /* Find the SEL_ARG sub-tree that corresponds to the chosen index. */
+ cur_index_tree= get_index_range_tree(cur_index, tree, param,
+ &cur_param_idx);
+ /* Check if this range tree can be used for prefix retrieval. */
+ cur_quick_prefix_records= check_quick_select(param, cur_param_idx,
+ cur_index_tree);
+ }
+ cost_group_min_max(table, cur_index_info, used_key_parts,
+ cur_group_key_parts, tree, cur_index_tree,
+ cur_quick_prefix_records, have_min, have_max,
+ &cur_read_cost, &cur_records);
+
+ if (cur_read_cost < best_read_cost)
+ {
+ index_info= cur_index_info;
+ index= cur_index;
+ best_read_cost= cur_read_cost;
+ best_records= cur_records;
+ best_index_tree= cur_index_tree;
+ best_quick_prefix_records= cur_quick_prefix_records;
+ best_param_idx= cur_param_idx;
+ group_key_parts= cur_group_key_parts;
+ group_prefix_len= cur_group_prefix_len;
+ }
+
+ next_index:
+ cur_group_key_parts= 0;
+ cur_group_prefix_len= 0;
+ }
+ if (!index_info) /* No usable index found. */
+ DBUG_RETURN(NULL);
+
+
+ /* Check (SA3,WA1) for the where clause. */
+ if (!check_group_min_max_predicates(join->conds, min_max_arg_item,
+ (index_info->flags & HA_SPATIAL) ?
+ Field::itMBR : Field::itRAW))
+ DBUG_RETURN(NULL);
+
+ /* The query passes all tests, so construct a new TRP object. */
+ read_plan= new (param->mem_root)
+ TRP_GROUP_MIN_MAX(have_min, have_max, min_max_arg_part,
+ group_prefix_len, used_key_parts,
+ group_key_parts, index_info, index,
+ key_infix_len,
+ (key_infix_len > 0) ? key_infix : NULL,
+ tree, best_index_tree, best_param_idx,
+ best_quick_prefix_records);
+ if (read_plan)
+ {
+ if (tree && read_plan->quick_prefix_records == 0)
+ DBUG_RETURN(NULL);
+
+ read_plan->read_cost= best_read_cost;
+ read_plan->records= best_records;
+
+ DBUG_PRINT("info",
+ ("Returning group min/max plan: cost: %g, records: %lu",
+ read_plan->read_cost, (ulong) read_plan->records));
+ }
+
+ DBUG_RETURN(read_plan);
+}
+
+
+/*
+ Check that the MIN/MAX attribute participates only in range predicates
+ with constants.
+
+ SYNOPSIS
+ check_group_min_max_predicates()
+ cond tree (or subtree) describing all or part of the WHERE
+ clause being analyzed
+ min_max_arg_item the field referenced by the MIN/MAX function(s)
+ min_max_arg_part the keypart of the MIN/MAX argument if any
+
+ DESCRIPTION
+ The function walks recursively over the cond tree representing a WHERE
+ clause, and checks condition (SA3) - if a field is referenced by a MIN/MAX
+ aggregate function, it is referenced only by one of the following
+ predicates: {=, !=, <, <=, >, >=, between, is null, is not null}.
+
+ RETURN
+ TRUE if cond passes the test
+ FALSE o/w
+*/
+
+static bool
+check_group_min_max_predicates(COND *cond, Item_field *min_max_arg_item,
+ Field::imagetype image_type)
+{
+ DBUG_ENTER("check_group_min_max_predicates");
+ if (!cond) /* If no WHERE clause, then all is OK. */
+ DBUG_RETURN(TRUE);
+
+ Item::Type cond_type= cond->type();
+ if (cond_type == Item::COND_ITEM) /* 'AND' or 'OR' */
+ {
+ DBUG_PRINT("info", ("Analyzing: %s", ((Item_func*) cond)->func_name()));
+ List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
+ Item *and_or_arg;
+ while ((and_or_arg= li++))
+ {
+ if(!check_group_min_max_predicates(and_or_arg, min_max_arg_item,
+ image_type))
+ DBUG_RETURN(FALSE);
+ }
+ DBUG_RETURN(TRUE);
+ }
+
+ DBUG_ASSERT(cond_type == Item::FUNC_ITEM);
+
+ /* Test if cond references only group-by or non-group fields. */
+ Item_func *pred= (Item_func*) cond;
+ Item **arguments= pred->arguments();
+ Item *cur_arg;
+ DBUG_PRINT("info", ("Analyzing: %s", pred->func_name()));
+ for (uint arg_idx= 0; arg_idx < pred->argument_count (); arg_idx++)
+ {
+ cur_arg= arguments[arg_idx];
+ DBUG_PRINT("info", ("cur_arg: %s", cur_arg->full_name()));
+ if (cur_arg->type() == Item::FIELD_ITEM)
+ {
+ if (min_max_arg_item && /* pred references min_max_arg_item. */
+ min_max_arg_item->eq(cur_arg, 1))
+ {/*
+ Check if pred is a range condition that compares the MIN/MAX argument
+ with a constant.
+ */
+ Item_func::Functype pred_type= pred->functype();
+ if (pred_type != Item_func::EQUAL_FUNC &&
+ pred_type != Item_func::LT_FUNC &&
+ pred_type != Item_func::LE_FUNC &&
+ pred_type != Item_func::GT_FUNC &&
+ pred_type != Item_func::GE_FUNC &&
+ pred_type != Item_func::BETWEEN &&
+ pred_type != Item_func::ISNULL_FUNC &&
+ pred_type != Item_func::ISNOTNULL_FUNC &&
+ pred_type != Item_func::EQ_FUNC &&
+ pred_type != Item_func::NE_FUNC)
+ DBUG_RETURN(FALSE);
+
+ /* Check that pred compares min_max_arg_item with a constant. */
+ Item *args[3];
+ bzero(args, 3 * sizeof(Item*));
+ bool inv;
+ /* Test if this is a comparison of a field and a constant. */
+ if (!simple_pred(pred, args, &inv))
+ DBUG_RETURN(FALSE);
+
+ /* Check for compatible string comparisons - similar to get_mm_leaf. */
+ if (args[0] && args[1] && !args[2] && // this is a binary function
+ min_max_arg_item->result_type() == STRING_RESULT &&
+ /*
+ Don't use an index when comparing strings of different collations.
+ */
+ ((args[1]->result_type() == STRING_RESULT &&
+ image_type == Field::itRAW &&
+ ((Field_str*) min_max_arg_item->field)->charset() !=
+ pred->compare_collation())
+ ||
+ /*
+ We can't always use indexes when comparing a string index to a
+ number.
+ */
+ (args[1]->result_type() != STRING_RESULT &&
+ min_max_arg_item->field->cmp_type() != args[1]->result_type())))
+ DBUG_RETURN(FALSE);
+ }
+ }
+ else if (cur_arg->type() == Item::FUNC_ITEM)
+ {
+ if(!check_group_min_max_predicates(cur_arg, min_max_arg_item,
+ image_type))
+ DBUG_RETURN(FALSE);
+ }
+ else if (cur_arg->const_item())
+ {
+ DBUG_RETURN(TRUE);
+ }
+ else
+ DBUG_RETURN(FALSE);
+ }
+
+ DBUG_RETURN(TRUE);
+}
+
+
+/*
+ Extract a sequence of constants from a conjunction of equality predicates.
+
+ SYNOPSIS
+ get_constant_key_infix()
+ index_info [in] Descriptor of the chosen index.
+ index_range_tree [in] Range tree for the chosen index
+ first_non_group_part [in] First index part after group attribute parts
+ min_max_arg_part [in] The keypart of the MIN/MAX argument if any
+ last_part [in] Last keypart of the index
+ thd [in] Current thread
+ key_infix [out] Infix of constants to be used for index lookup
+ key_infix_len [out] Lenghth of the infix
+ first_non_infix_part [out] The first keypart after the infix (if any)
+
+ DESCRIPTION
+ Test conditions (NGA1, NGA2) from get_best_group_min_max(). Namely,
+ for each keypart field NGF_i not in GROUP-BY, check that there is a constant
+ equality predicate among conds with the form (NGF_i = const_ci) or
+ (const_ci = NGF_i).
+ Thus all the NGF_i attributes must fill the 'gap' between the last group-by
+ attribute and the MIN/MAX attribute in the index (if present). If these
+ conditions hold, copy each constant from its corresponding predicate into
+ key_infix, in the order its NG_i attribute appears in the index, and update
+ key_infix_len with the total length of the key parts in key_infix.
+
+ RETURN
+ TRUE if the index passes the test
+ FALSE o/w
+*/
+
+static bool
+get_constant_key_infix(KEY *index_info, SEL_ARG *index_range_tree,
+ KEY_PART_INFO *first_non_group_part,
+ KEY_PART_INFO *min_max_arg_part,
+ KEY_PART_INFO *last_part, THD *thd,
+ byte *key_infix, uint *key_infix_len,
+ KEY_PART_INFO **first_non_infix_part)
+{
+ SEL_ARG *cur_range;
+ KEY_PART_INFO *cur_part;
+ /* End part for the first loop below. */
+ KEY_PART_INFO *end_part= min_max_arg_part ? min_max_arg_part : last_part;
+
+ *key_infix_len= 0;
+ byte *key_ptr= key_infix;
+ for (cur_part= first_non_group_part; cur_part != end_part; cur_part++)
+ {
+ /*
+ Find the range tree for the current keypart. We assume that
+ index_range_tree points to the leftmost keypart in the index.
+ */
+ for (cur_range= index_range_tree; cur_range;
+ cur_range= cur_range->next_key_part)
+ {
+ if (cur_range->field->eq(cur_part->field))
+ break;
+ }
+ if (!cur_range)
+ {
+ if (min_max_arg_part)
+ return FALSE; /* The current keypart has no range predicates at all. */
+ else
+ {
+ *first_non_infix_part= cur_part;
+ return TRUE;
+ }
+ }
+
+ /* Check that the current range tree is a single point interval. */
+ if (cur_range->prev || cur_range->next)
+ return FALSE; /* This is not the only range predicate for the field. */
+ if ((cur_range->min_flag & NO_MIN_RANGE) ||
+ (cur_range->max_flag & NO_MAX_RANGE) ||
+ (cur_range->min_flag & NEAR_MIN) || (cur_range->max_flag & NEAR_MAX))
+ return FALSE;
+
+ uint field_length= cur_part->store_length;
+ if ((cur_range->maybe_null &&
+ cur_range->min_value[0] && cur_range->max_value[0])
+ ||
+ (memcmp(cur_range->min_value, cur_range->max_value, field_length) == 0))
+ { /* cur_range specifies 'IS NULL' or an equality condition. */
+ memcpy(key_ptr, cur_range->min_value, field_length);
+ key_ptr+= field_length;
+ *key_infix_len+= field_length;
+ }
+ else
+ return FALSE;
+ }
+
+ if (!min_max_arg_part && (cur_part == last_part))
+ *first_non_infix_part= last_part;
+
+ return TRUE;
+}
+
+
+/*
+ Find the key part referenced by a field.
+
+ SYNOPSIS
+ get_field_keypart()
+ index descriptor of an index
+ field field that possibly references some key part in index
+
+ NOTES
+ The return value can be used to get a KEY_PART_INFO pointer by
+ part= index->key_part + get_field_keypart(...) - 1;
+
+ RETURN
+ Positive number which is the consecutive number of the key part, or
+ 0 if field does not reference any index field.
+*/
+
+static inline uint
+get_field_keypart(KEY *index, Field *field)
+{
+ KEY_PART_INFO *part= index->key_part;
+ uint key_part_num= 0;
+
+ while (part != part + index->key_parts)
+ {
+ key_part_num++;
+ if (field->eq(part->field))
+ return key_part_num;
+ part++;
+ }
+ return key_part_num;
+}
+
+
+/*
+ Find the SEL_ARG sub-tree that corresponds to the chosen index.
+
+ SYNOPSIS
+ get_index_range_tree()
+ index [in] The ID of the index being looked for
+ range_tree[in] Tree of ranges being searched
+ param [in] PARAM from SQL_SELECT::test_quick_select
+ param_idx [out] Index in the array PARAM::key that corresponds to 'index'
+
+ DESCRIPTION
+
+ A SEL_TREE contains range trees for all usable indexes. This procedure
+ finds the SEL_ARG sub-tree for 'index'. The members of a SEL_TREE are
+ ordered in the same way as the members of PARAM::key, thus we first find
+ the corresponding index in the array PARAM::key. This index is returned
+ through the variable param_idx, to be used later as argument of
+ check_quick_select().
+
+ RETURN
+ Pointer to the SEL_ARG subtree that corresponds to index.
+*/
+
+SEL_ARG * get_index_range_tree(uint index, SEL_TREE* range_tree, PARAM *param,
+ uint *param_idx)
+{
+ uint idx= 0; /* Index nr in param->key_parts */
+ while (idx < param->keys)
+ {
+ if (index == param->real_keynr[idx])
+ break;
+ idx++;
+ }
+ *param_idx= idx;
+ return(range_tree->keys[idx]);
+}
+
+
+TRP_GROUP_MIN_MAX::TRP_GROUP_MIN_MAX(bool have_min, bool have_max,
+ KEY_PART_INFO *min_max_arg_part,
+ uint group_prefix_len, uint used_key_parts,
+ uint group_key_parts, KEY *index_info,
+ uint index, uint key_infix_len,
+ byte *key_infix, SEL_TREE *tree,
+ SEL_ARG *index_tree, uint param_idx,
+ ha_rows quick_prefix_records)
+ : have_min(have_min), have_max(have_max), min_max_arg_part(min_max_arg_part),
+ group_prefix_len(group_prefix_len), used_key_parts(used_key_parts),
+ group_key_parts(group_key_parts), index_info(index_info), index(index),
+ key_infix_len(key_infix_len), range_tree(tree), index_tree(index_tree),
+ param_idx(param_idx), quick_prefix_records(quick_prefix_records)
+{
+ if (key_infix_len)
+ memcpy(this->key_infix, key_infix, key_infix_len);
+}
+
+
+/*
+ Compute the cost of a quick_group_min_max_select for a particular index.
+
+ SYNOPSIS
+ cost_group_min_max()
+ table [in] The table being accessed
+ index_info [in] The index used to access the table
+ used_key_parts [in] Number of key parts used to access the index
+ group_key_parts [in] Number of index key parts in the group prefix
+ range_tree [in] Tree of ranges for all indexes
+ index_tree [in] The range tree for the current index
+ quick_prefix_records [in] Number of records retrieved by the internally used
+ quick range select if any
+ have_min [in] True if there is a MIN function
+ have_max [in] True if there is a MAX function
+ read_cost [out] The cost to retrieve rows via this quick select
+ records [out] The number of rows retrieved
+
+ DESCRIPTION
+ This method computes the access cost of a TRP_GROUP_MIN_MAX instance and the
+ number of rows returned. It updates this->read_cost and this->records.
+
+ NOTES
+ The cost computation distinguishes several cases:
+ 1) No equality predicates over non-group attributes (thus no key_infix).
+ If groups are bigger than blocks on the average, then we assume that it
+ is very unlikely that block ends are aligned with group ends, thus even
+ if we look for both MIN and MAX keys, all pairs of neighbor MIN/MAX
+ keys, except for the first MIN and the last MAX keys, will be in the
+ same block. If groups are smaller than blocks, then we are going to
+ read all blocks.
+ 2) There are equality predicates over non-group attributes.
+ In this case the group prefix is extended by additional constants, and
+ as a result the min/max values are inside sub-groups of the original
+ groups. The number of blocks that will be read depends on whether the
+ ends of these sub-groups will be contained in the same or in different
+ blocks. We compute the probability for the two ends of a subgroup to be
+ in two different blocks as the ratio of:
+ - the number of positions of the left-end of a subgroup inside a group,
+ such that the right end of the subgroup is past the end of the buffer
+ containing the left-end, and
+ - the total number of possible positions for the left-end of the
+ subgroup, which is the number of keys in the containing group.
+ We assume it is very unlikely that two ends of subsequent subgroups are
+ in the same block.
+ 3) The are range predicates over the group attributes.
+ Then some groups may be filtered by the range predicates. We use the
+ selectivity of the range predicates to decide how many groups will be
+ filtered.
+
+ TODO
+ - Take into account the optional range predicates over the MIN/MAX
+ argument.
+ - Check if we have a PK index and we use all cols - then each key is a
+ group, and it will be better to use an index scan.
+
+ RETURN
+ None
+*/
+
+void cost_group_min_max(TABLE* table, KEY *index_info, uint used_key_parts,
+ uint group_key_parts, SEL_TREE *range_tree,
+ SEL_ARG *index_tree, ha_rows quick_prefix_records,
+ bool have_min, bool have_max,
+ double *read_cost, ha_rows *records)
+{
+ uint table_records;
+ uint num_groups;
+ uint num_blocks;
+ uint keys_per_block;
+ uint keys_per_group;
+ uint keys_per_subgroup; /* Average number of keys in sub-groups */
+ /* formed by a key infix. */
+ double p_overlap; /* Probability that a sub-group overlaps two blocks. */
+ double quick_prefix_selectivity;
+ double io_cost;
+ double cpu_cost= 0; /* TODO: CPU cost of index_read calls? */
+
+ DBUG_ENTER("TRP_GROUP_MIN_MAX::cost");
+ table_records= table->file->records;
+ keys_per_block= (table->file->block_size / 2 /
+ (index_info->key_length + table->file->ref_length)
+ + 1);
+ num_blocks= (table_records / keys_per_block) + 1;
+
+ /* Compute the number of keys in a group. */
+ keys_per_group= index_info->rec_per_key[group_key_parts - 1];
+ if (keys_per_group == 0) /* If there is no statistics try to guess */
+ /* each group contains 10% of all records */
+ keys_per_group= (table_records / 10) + 1;
+ num_groups= (table_records / keys_per_group) + 1;
+
+ /* Apply the selectivity of the quick select for group prefixes. */
+ if (range_tree && (quick_prefix_records != HA_POS_ERROR))
+ {
+ quick_prefix_selectivity= (double) quick_prefix_records /
+ (double) table_records;
+ num_groups= (uint) round(num_groups * quick_prefix_selectivity);
+ }
+
+ if (used_key_parts > group_key_parts)
+ { /*
+ Compute the probability that two ends of a subgroup are inside
+ different blocks.
+ */
+ keys_per_subgroup= index_info->rec_per_key[used_key_parts - 1];
+ if (keys_per_subgroup >= keys_per_block) /* If a subgroup is bigger than */
+ p_overlap= 1.0; /* a block, it will overlap at least two blocks. */
+ else
+ {
+ double blocks_per_group= (double) num_blocks / (double) num_groups;
+ p_overlap= (blocks_per_group * (keys_per_subgroup - 1)) / keys_per_group;
+ p_overlap= min(p_overlap, 1.0);
+ }
+ io_cost= (double) min(num_groups * (1 + p_overlap), num_blocks);
+ }
+ else
+ io_cost= (keys_per_group > keys_per_block) ?
+ (have_min && have_max) ? (double) (num_groups + 1) :
+ (double) num_groups :
+ (double) num_blocks;
+
+ /*
+ TODO: If there is no WHERE clause and no other expressions, there should be
+ no CPU cost. We leave it here to make this cost comparable to that of index
+ scan as computed in SQL_SELECT::test_quick_select().
+ */
+ cpu_cost= (double) num_groups / TIME_FOR_COMPARE;
+
+ *read_cost= io_cost + cpu_cost;
+ *records= num_groups;
+
+ DBUG_PRINT("info",
+ ("records=%u, keys/block=%u, keys/group=%u, records=%u, blocks=%u",
+ table_records, keys_per_block, keys_per_group, records,
+ num_blocks));
+ DBUG_VOID_RETURN;
+}
+
+
+/*
+ Construct a new quick select object for queries with group by with min/max.
+
+ SYNOPSIS
+ TRP_GROUP_MIN_MAX::make_quick()
+ param Parameter from test_quick_select
+ retrieve_full_rows ignored
+ parent_alloc Memory pool to use, if any.
+
+ NOTES
+ Make_quick ignores the retrieve_full_rows parameter because
+ QUICK_GROUP_MIN_MAX_SELECT always performs 'index only' scans.
+ The other parameter are ignored as well because all necessary
+ data to create the QUICK object is computed at this TRP creation
+ time.
+
+ RETURN
+ New QUICK_GROUP_MIN_MAX_SELECT object if successfully created,
+ NULL o/w.
+*/
+
+QUICK_SELECT_I *
+TRP_GROUP_MIN_MAX::make_quick(PARAM *param, bool retrieve_full_rows,
+ MEM_ROOT *parent_alloc)
+{
+ QUICK_GROUP_MIN_MAX_SELECT *quick;
+
+ DBUG_ENTER("TRP_GROUP_MIN_MAX::make_quick");
+
+ quick= new QUICK_GROUP_MIN_MAX_SELECT(param->table,
+ param->thd->lex->select_lex.join,
+ have_min, have_max, min_max_arg_part,
+ group_prefix_len, used_key_parts,
+ index_info, index, read_cost, records,
+ key_infix_len, key_infix, parent_alloc);
+ if (!quick)
+ DBUG_RETURN(NULL);
+
+ if (quick->init())
+ {
+ delete quick;
+ DBUG_RETURN(NULL);
+ }
+
+ if (range_tree)
+ {
+ DBUG_ASSERT(quick_prefix_records > 0);
+ if (quick_prefix_records == HA_POS_ERROR)
+ quick->quick_prefix_select= NULL; /* Can't construct a quick select. */
+ else
+ /* Make a QUICK_RANGE_SELECT to be used for group prefix retrieval. */
+ quick->quick_prefix_select= get_quick_select(param, param_idx, index_tree,
+ &quick->alloc);
+
+ /*
+ Extract the SEL_ARG subtree that contains only ranges for the MIN/MAX
+ attribute, and create an array of QUICK_RANGES to be used by the
+ new quick select.
+ */
+ if (min_max_arg_part)
+ {
+ SEL_ARG *min_max_range= index_tree;
+ while (min_max_range) /* Find the tree for the MIN/MAX key part. */
+ {
+ if (min_max_range->field->eq(min_max_arg_part->field))
+ break;
+ min_max_range= min_max_range->next_key_part;
+ }
+ /* Scroll to the leftmost interval for the MIN/MAX argument. */
+ while (min_max_range && min_max_range->prev)
+ min_max_range= min_max_range->prev;
+ /* Create an array of QUICK_RANGEs for the MIN/MAX argument. */
+ while (min_max_range)
+ {
+ if (quick->add_range(min_max_range))
+ {
+ delete quick;
+ quick= NULL;
+ DBUG_RETURN(NULL);
+ }
+ min_max_range= min_max_range->next;
+ }
+ }
+ }
+ else
+ quick->quick_prefix_select= NULL;
+
+ quick->update_key_stat();
+
+ DBUG_RETURN(quick);
+}
+
+
+/*
+ Construct new quick select for group queries with min/max.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::QUICK_GROUP_MIN_MAX_SELECT()
+ table The table being accessed
+ join Descriptor of the current query
+ have_min TRUE if the query selects a MIN function
+ have_max TRUE if the query selects a MAX function
+ min_max_arg_part The only argument field of all MIN/MAX functions
+ group_prefix_len Length of all key parts in the group prefix
+ prefix_key_parts All key parts in the group prefix
+ index_info The index chosen for data access
+ use_index The id of index_info
+ read_cost Cost of this access method
+ records Number of records returned
+ key_infix_len Length of the key infix appended to the group prefix
+ key_infix Infix of constants from equality predicates
+ parent_alloc Memory pool for this and quick_prefix_select data
+
+ RETURN
+ None
+*/
+
+QUICK_GROUP_MIN_MAX_SELECT::QUICK_GROUP_MIN_MAX_SELECT(
+ TABLE *table, JOIN *join, bool have_min, bool have_max,
+ KEY_PART_INFO *min_max_arg_part, uint group_prefix_len, uint used_key_parts,
+ KEY *index_info, uint use_index, double read_cost, ha_rows records,
+ uint key_infix_len, byte *key_infix, MEM_ROOT *parent_alloc)
+: join(join), index_info(index_info), group_prefix_len(group_prefix_len),
+ have_min(have_min), have_max(have_max), seen_first_key(FALSE),
+ min_max_arg_part(min_max_arg_part), key_infix(key_infix),
+ key_infix_len(key_infix_len)
+{
+ head= table;
+ file= head->file;
+ index= use_index;
+ record= head->record[0];
+ tmp_record= head->record[1];
+ this->read_time= read_cost;
+ this->records= records;
+ this->used_key_parts= used_key_parts;
+ real_prefix_len= group_prefix_len + key_infix_len;
+ group_prefix= NULL;
+ min_max_arg_len= min_max_arg_part ? min_max_arg_part->store_length : 0;
+ if (!parent_alloc)
+ {
+ init_sql_alloc(&alloc, join->thd->variables.range_alloc_block_size, 0);
+ my_pthread_setspecific_ptr(THR_MALLOC,&alloc);
+ }
+ else
+ bzero(&alloc, sizeof(MEM_ROOT));
+}
+
+
+/*
+ Do post-constructor initialization.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::init()
+
+ DESCRIPTION
+ The method performs initialization that cannot be done in the constructor
+ such as memory allocations that may fail. It allocates memory for the
+ group prefix and inifix buffers, and for the lists of MIN/MAX item to be
+ updated during execution.
+
+ RETURN
+ 0 OK
+ other Error code
+*/
+
+int QUICK_GROUP_MIN_MAX_SELECT::init()
+{
+ if (group_prefix) /* Already initialized. */
+ return 0;
+
+ if (!(last_prefix= (byte*) alloc_root(&alloc, group_prefix_len)))
+ return 1;
+ /*
+ We may use group_prefix to store keys with all select fields, so allocate
+ enough space for it.
+ */
+ if (!(group_prefix= (byte*) alloc_root(&alloc,
+ real_prefix_len + min_max_arg_len)))
+ return 1;
+
+ if (key_infix_len > 0)
+ {
+ /*
+ The memory location pointed to by key_infix will be deleted soon, so
+ allocate a new buffer and copy the key_infix into it.
+ */
+ byte *tmp_key_infix= (byte*) alloc_root(&alloc, key_infix_len);
+ if (!tmp_key_infix)
+ return 1;
+ memcpy(tmp_key_infix, this->key_infix, key_infix_len);
+ this->key_infix= tmp_key_infix;
+ }
+
+ if (min_max_arg_part)
+ {
+ if(my_init_dynamic_array(&min_max_ranges, sizeof(QUICK_RANGE*), 16, 16))
+ return 1;
+
+ if (have_min)
+ {
+ if(!(min_functions= new List<Item_sum>))
+ return 1;
+ }
+ else
+ min_functions= NULL;
+ if (have_max)
+ {
+ if(!(max_functions= new List<Item_sum>))
+ return 1;
+ }
+ else
+ max_functions= NULL;
+
+ Item_sum *min_max_item;
+ Item_sum **func_ptr= join->sum_funcs;
+ while ((min_max_item= *(func_ptr++)))
+ {
+ if (have_min && (min_max_item->sum_func() == Item_sum::MIN_FUNC))
+ min_functions->push_back(min_max_item);
+ else if (have_max && (min_max_item->sum_func() == Item_sum::MAX_FUNC))
+ max_functions->push_back(min_max_item);
+ }
+
+ if (have_min)
+ {
+ if (!(min_functions_it= new List_iterator<Item_sum>(*min_functions)))
+ return 1;
+ }
+ else
+ min_functions_it= NULL;
+
+ if (have_max)
+ {
+ if (!(max_functions_it= new List_iterator<Item_sum>(*max_functions)))
+ return 1;
+ }
+ else
+ max_functions_it= NULL;
+ }
+
+ return 0;
+}
+
+
+QUICK_GROUP_MIN_MAX_SELECT::~QUICK_GROUP_MIN_MAX_SELECT()
+{
+ DBUG_ENTER("QUICK_GROUP_MIN_MAX_SELECT::~QUICK_GROUP_MIN_MAX_SELECT");
+ if (file->inited != handler::NONE)
+ file->ha_index_end();
+ if (min_max_arg_part)
+ delete_dynamic(&min_max_ranges);
+ free_root(&alloc,MYF(0));
+ delete quick_prefix_select;
+ DBUG_VOID_RETURN;
+}
+
+
+/*
+ Eventually create and add a new quick range object.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::add_range()
+ sel_range Range object from which a
+
+ NOTES
+ Construct a new QUICK_RANGE object from a SEL_ARG object, and
+ add it to the array min_max_ranges. If sel_arg is an infinite
+ range, e.g. (x < 5 or x > 4), then skip it and do not construct
+ a quick range.
+
+ RETURN
+ FALSE on success
+ TRUE otherwise
+*/
+
+bool QUICK_GROUP_MIN_MAX_SELECT::add_range(SEL_ARG *sel_range)
+{
+ QUICK_RANGE *range;
+ uint range_flag= sel_range->min_flag | sel_range->max_flag;
+
+ /* Skip (-inf,+inf) ranges, e.g. (x < 5 or x > 4). */
+ if((range_flag & NO_MIN_RANGE) && (range_flag & NO_MAX_RANGE))
+ return FALSE;
+
+ if (!(sel_range->min_flag & NO_MIN_RANGE) &&
+ !(sel_range->max_flag & NO_MAX_RANGE))
+ {
+ if (sel_range->maybe_null &&
+ sel_range->min_value[0] && sel_range->max_value[0])
+ range_flag|= NULL_RANGE; /* IS NULL condition */
+ else if (memcmp(sel_range->min_value, sel_range->max_value,
+ min_max_arg_len) == 0)
+ range_flag|= EQ_RANGE; /* equality condition */
+ }
+ range= new QUICK_RANGE(sel_range->min_value, min_max_arg_len,
+ sel_range->max_value, min_max_arg_len,
+ range_flag);
+ if (!range)
+ return TRUE;
+ if (insert_dynamic(&min_max_ranges, (gptr)&range))
+ return TRUE;
+ return FALSE;
+}
+
+
+/*
+ Determine the total number and length of the keys that will be used for
+ index lookup.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::update_key_stat()
+
+ DESCRIPTION
+ The total length of the keys used for index lookup depends on whether
+ there are any predicates referencing the min/max argument, and/or if
+ the min/max argument field can be NULL.
+ This function does an optimistic analysis whether the search key might
+ be extended by a constant for the min/max keypart. It is 'optimistic'
+ because during actual execution it may happen that a particular range
+ is skipped, and then a shorter key will be used. However this is data
+ dependent and can't be easily estimated here.
+
+ RETURN
+ None
+*/
+
+void QUICK_GROUP_MIN_MAX_SELECT::update_key_stat()
+{
+ max_used_key_length= real_prefix_len;
+ if (min_max_ranges.elements > 0)
+ {
+ QUICK_RANGE *cur_range;
+ if (have_min)
+ { /* Check if the right-most range has a lower boundary. */
+ get_dynamic(&min_max_ranges, (gptr)&cur_range,
+ min_max_ranges.elements - 1);
+ if (!(cur_range->flag & NO_MIN_RANGE))
+ {
+ max_used_key_length+= min_max_arg_len;
+ ++used_key_parts;
+ return;
+ }
+ }
+ if (have_max)
+ { /* Check if the left-most range has an upper boundary. */
+ get_dynamic(&min_max_ranges, (gptr)&cur_range, 0);
+ if (!(cur_range->flag & NO_MAX_RANGE))
+ {
+ max_used_key_length+= min_max_arg_len;
+ ++used_key_parts;
+ return;
+ }
+ }
+ }
+ else if (have_min && min_max_arg_part && min_max_arg_part->field->is_null())
+ {
+ max_used_key_length+= min_max_arg_len;
+ ++used_key_parts;
+ }
+}
+
+
+/*
+ Initialize a quick group min/max select for key retrieval.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::reset()
+
+ DESCRIPTION
+ Initialize the index chosen for access and find and store the prefix
+ of the last group. The method is expensive since it performs disk access.
+
+ RETURN
+ 0 OK
+ other Error code
+*/
+
+int QUICK_GROUP_MIN_MAX_SELECT::reset(void)
+{
+ int result;
+ DBUG_ENTER("QUICK_GROUP_MIN_MAX_SELECT::reset");
+
+ file->extra(HA_EXTRA_KEYREAD); /* We need only the key attributes */
+ result= file->ha_index_init(index);
+ result= file->index_last(record);
+ if (quick_prefix_select)
+ quick_prefix_select->reset();
+ if (result)
+ DBUG_RETURN(result);
+ /* Save the prefix of the last group. */
+ key_copy(last_prefix, record, index_info, group_prefix_len);
+
+ DBUG_RETURN(0);
+}
+
+
+
+/*
+ Get the next key containing the MIN and/or MAX key for the next group.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::get_next()
+
+ DESCRIPTION
+ The method finds the next subsequent group of records that satisfies the
+ query conditions and finds the keys that contain the MIN/MAX values for
+ the key part referenced by the MIN/MAX function(s). Once a group and its
+ MIN/MAX values are found, store these values in the Item_sum objects for
+ the MIN/MAX functions. The rest of the values in the result row are stored
+ in the Item_field::result_field of each select field. If the query does
+ not contain MIN and/or MAX functions, then the function only finds the
+ group prefix, which is a query answer itself.
+
+ NOTES
+ If both MIN and MAX are computed, then we use the fact that if there is
+ no MIN key, there can't be a MAX key as well, so we can skip looking
+ for a MAX key in this case.
+
+ RETURN
+ 0 on success
+ HA_ERR_END_OF_FILE if returned all keys
+ other if some error occurred
+*/
+
+int QUICK_GROUP_MIN_MAX_SELECT::get_next()
+{
+ int min_res= 0;
+ int max_res= 0;
+ int result;
+ int is_last_prefix;
+
+ DBUG_ENTER("QUICK_GROUP_MIN_MAX_SELECT::get_next");
+
+ /*
+ Loop until a group is found that satisfies all query conditions or the last
+ group is reached.
+ */
+ do
+ {
+ result= next_prefix();
+ /*
+ Check if this is the last group prefix. Notice that at this point
+ this->record contains the current prefix in record format.
+ */
+ is_last_prefix= key_cmp(index_info->key_part, last_prefix,
+ group_prefix_len);
+ DBUG_ASSERT(is_last_prefix <= 0);
+ if (result == HA_ERR_KEY_NOT_FOUND)
+ continue;
+ else if (result)
+ break;
+
+ if (have_min)
+ {
+ min_res= next_min();
+ if (min_res == 0)
+ update_min_result();
+ }
+ /* If there is no MIN in the group, there is no MAX either. */
+ if ((have_max && !have_min) ||
+ (have_max && have_min && (min_res == 0)))
+ {
+ max_res= next_max();
+ if (max_res == 0)
+ update_max_result();
+ /* If a MIN was found, a MAX must have been found as well. */
+ DBUG_ASSERT((have_max && !have_min) ||
+ (have_max && have_min && (max_res == 0)));
+ }
+ result= have_min ? min_res : have_max ? max_res : result;
+ }
+ while (result == HA_ERR_KEY_NOT_FOUND && is_last_prefix != 0);
+
+ if (result == 0)
+ /*
+ Partially mimic the behavior of end_select_send. Copy the
+ field data from Item_field::field into Item_field::result_field
+ of each non-aggregated field (the group fields, and optionally
+ other fields in non-ANSI SQL mode).
+ */
+ copy_fields(&join->tmp_table_param);
+ else if (result == HA_ERR_KEY_NOT_FOUND)
+ result= HA_ERR_END_OF_FILE;
+
+ DBUG_RETURN(result);
+}
+
+
+/*
+ Retrieve the minimal key in the next group.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::next_min()
+
+ DESCRIPTION
+ Load the prefix of the next group into group_prefix and find the minimal
+ key within this group such that the key satisfies the query conditions and
+ NULL semantics. The found key is loaded into this->record.
+
+ IMPLEMENTATION
+ Depending on the values of min_max_ranges.elements, key_infix_len, and
+ whether there is a NULL in the MIN field, this function may directly
+ return without any data access. In this case we use the key loaded into
+ this->record by the call to this->next_prefix() just before this call.
+
+ RETURN
+ 0 on success
+ HA_ERR_KEY_NOT_FOUND if no MIN key was found that fulfills all conditions.
+ other if some error occurred
+*/
+
+int QUICK_GROUP_MIN_MAX_SELECT::next_min()
+{
+ int result= 0;
+ DBUG_ENTER("QUICK_GROUP_MIN_MAX_SELECT::next_min");
+
+ /* Find the MIN key using the eventually extended group prefix. */
+ if (min_max_ranges.elements > 0)
+ {
+ if ((result= next_min_in_range()))
+ DBUG_RETURN(result);
+ }
+ else
+ {
+ /* Apply the constant equality conditions to the non-group select fields. */
+ if (key_infix_len > 0)
+ {
+ if ((result= file->index_read(record, group_prefix, real_prefix_len,
+ HA_READ_KEY_EXACT)))
+ DBUG_RETURN(result);
+ }
+
+ /*
+ If the min/max argument field is NULL, skip subsequent rows in the same
+ group with NULL in it. Notice that:
+ - if the first row in a group doesn't have a NULL in the field, no row
+ in the same group has (because NULL < any other value),
+ - min_max_arg_part->field->ptr points to some place in 'record'.
+ */
+ if (min_max_arg_part && min_max_arg_part->field->is_null())
+ {
+ /* Find the first subsequent record without NULL in the MIN/MAX field. */
+ key_copy(tmp_record, record, index_info, 0);
+ result= file->index_read(record, tmp_record,
+ real_prefix_len + min_max_arg_len,
+ HA_READ_AFTER_KEY);
+ /*
+ Check if the new record belongs to the current group by comparing its
+ prefix with the group's prefix. If it is from the next group, then the
+ whole group has NULLs in the MIN/MAX field, so use the first record in
+ the group as a result.
+ TODO:
+ It is possible to reuse this new record as the result candidate for the
+ next call to next_min(), and to save one lookup in the next call. For
+ this add a new member 'this->next_group_prefix'.
+ */
+ if (!result)
+ {
+ if(key_cmp(index_info->key_part, group_prefix, real_prefix_len))
+ key_restore(record, tmp_record, index_info, 0);
+ } else if (result == HA_ERR_KEY_NOT_FOUND)
+ result= 0; /* There is a result in any case. */
+ }
+ }
+
+ /*
+ If the MIN attribute is non-nullable, this->record already contains the
+ MIN key in the group, so just return.
+ */
+ DBUG_RETURN(result);
+}
+
+
+/*
+ Retrieve the maximal key in the next group.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::next_max()
+
+ DESCRIPTION
+ If there was no previous next_min call to determine the next group prefix,
+ then load the next prefix into group_prefix, then lookup the maximal key of
+ the group, and store it into this->record.
+
+ RETURN
+ 0 on success
+ HA_ERR_KEY_NOT_FOUND if no MAX key was found that fulfills all conditions.
+ other if some error occurred
+*/
+
+int QUICK_GROUP_MIN_MAX_SELECT::next_max()
+{
+ int result;
+
+ DBUG_ENTER("QUICK_GROUP_MIN_MAX_SELECT::next_max");
+
+ /* Get the last key in the (possibly extended) group. */
+ if (min_max_ranges.elements > 0)
+ result= next_max_in_range();
+ else
+ result= file->index_read(record, group_prefix, real_prefix_len,
+ HA_READ_PREFIX_LAST);
+ DBUG_RETURN(result);
+}
+
+
+/*
+ Determine the prefix of the next group.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::next_prefix()
+
+ DESCRIPTION
+ Determine the prefix of the next group that satisfies the query conditions.
+ If there is a range condition referencing the group attributes, use a
+ QUICK_RANGE_SELECT object to retrieve the *first* key that satisfies the
+ condition. If there is a key infix of constants, append this infix
+ immediately after the group attributes. The possibly extended prefix is
+ stored in this->group_prefix. The first key of the found group is stored in
+ this->record, on which relies this->next_min().
+
+ RETURN
+ 0 on success
+ HA_ERR_KEY_NOT_FOUND if there is no key with the formed prefix
+ HA_ERR_END_OF_FILE if there are no more keys
+ other if some error occurred
+*/
+int QUICK_GROUP_MIN_MAX_SELECT::next_prefix()
+{
+ int result;
+ DBUG_ENTER("QUICK_GROUP_MIN_MAX_SELECT::next_prefix");
+
+ if (quick_prefix_select)
+ {
+ byte *cur_prefix= seen_first_key ? group_prefix : NULL;
+ if ((result= quick_prefix_select->get_next_prefix(group_prefix_len,
+ cur_prefix)))
+ DBUG_RETURN(result);
+ seen_first_key= TRUE;
+ }
+ else
+ {
+ if (!seen_first_key)
+ {
+ result= file->index_first(record);
+ if (result)
+ DBUG_RETURN(result);
+ seen_first_key= TRUE;
+ }
+ else
+ {
+ /* Load the first key in this group into record. */
+ result= file->index_read(record, group_prefix, group_prefix_len,
+ HA_READ_AFTER_KEY);
+ if (result)
+ DBUG_RETURN(result);
+ }
+ }
+
+ /* Save the prefix of this group for subsequent calls. */
+ key_copy(group_prefix, record, index_info, group_prefix_len);
+ /* Append key_infix to group_prefix. */
+ if (key_infix_len > 0)
+ memcpy(group_prefix + group_prefix_len,
+ key_infix, key_infix_len);
+
+ DBUG_RETURN(0);
+}
+
+
+/*
+ Find the minimal key in a group that satisfies some range conditions for the
+ min/max argument field.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::next_min_in_range()
+
+ DESCRIPTION
+ Given the sequence of ranges min_max_ranges, find the minimal key that is
+ in the left-most possible range. If there is no such key, then the current
+ group does not have a MIN key that satisfies the WHERE clause. If a key is
+ found, its value is stored in this->record.
+
+ RETURN
+ 0 on success
+ HA_ERR_KEY_NOT_FOUND if there is no key with the given prefix in any of
+ the ranges
+ other if some error
+*/
+
+int QUICK_GROUP_MIN_MAX_SELECT::next_min_in_range()
+{
+ ha_rkey_function find_flag;
+ uint search_prefix_len;
+ QUICK_RANGE *cur_range;
+ bool found_null= FALSE;
+ int result= HA_ERR_KEY_NOT_FOUND;
+
+ DBUG_ASSERT(min_max_ranges.elements > 0);
+
+ for (uint range_idx= 0; range_idx < min_max_ranges.elements; range_idx++)
+ { /* Search from the left-most range to the right. */
+ get_dynamic(&min_max_ranges, (gptr)&cur_range, range_idx);
+
+ /*
+ If the current value for the min/max argument is bigger than the right
+ boundary of cur_range, there is no need to check this range.
+ */
+ if (range_idx != 0 && !(cur_range->flag & NO_MAX_RANGE) &&
+ (key_cmp(min_max_arg_part, cur_range->max_key, min_max_arg_len) == 1))
+ continue;
+
+ if (cur_range->flag & NO_MIN_RANGE)
+ {
+ find_flag= HA_READ_KEY_EXACT;
+ search_prefix_len= real_prefix_len;
+ }
+ else
+ {
+ /* Extend the search key with the lower boundary for this range. */
+ memcpy(group_prefix + real_prefix_len, cur_range->min_key,
+ cur_range->min_length);
+ search_prefix_len= real_prefix_len + min_max_arg_len;
+ find_flag= (cur_range->flag & (EQ_RANGE | NULL_RANGE)) ?
+ HA_READ_KEY_EXACT : (cur_range->flag & NEAR_MIN) ?
+ HA_READ_AFTER_KEY : HA_READ_KEY_OR_NEXT;
+ }
+
+ result= file->index_read(record, group_prefix, search_prefix_len,
+ find_flag);
+ if ((result == HA_ERR_KEY_NOT_FOUND) &&
+ (cur_range->flag & (EQ_RANGE | NULL_RANGE)))
+ continue; /* Check the next range. */
+ else if (result)
+ /*
+ In all other cases (HA_ERR_*, HA_READ_KEY_EXACT with NO_MIN_RANGE,
+ HA_READ_AFTER_KEY, HA_READ_KEY_OR_NEXT) if the lookup failed for this
+ range, it can't succeed for any other subsequent range.
+ */
+ break;
+
+ /* A key was found. */
+ if (cur_range->flag & EQ_RANGE)
+ break; /* No need to perform the checks below for equal keys. */
+
+ if (cur_range->flag & NULL_RANGE)
+ { /* Remember this key, and continue looking for a non-NULL key that */
+ /* satisfies some other condition. */
+ memcpy(tmp_record, record, head->rec_buff_length);
+ found_null= TRUE;
+ continue;
+ }
+
+ /* Check if record belongs to the current group. */
+ if (key_cmp(index_info->key_part, group_prefix, real_prefix_len))
+ {
+ result = HA_ERR_KEY_NOT_FOUND;
+ continue;
+ }
+
+ /* If there is an upper limit, check if the found key is in the range. */
+ if ( !(cur_range->flag & NO_MAX_RANGE) )
+ {
+ /* Compose the MAX key for the range. */
+ byte *max_key= (byte*) my_alloca(real_prefix_len + min_max_arg_len);
+ memcpy(max_key, group_prefix, real_prefix_len);
+ memcpy(max_key + real_prefix_len, cur_range->max_key,
+ cur_range->max_length);
+ /* Compare the found key with max_key. */
+ int cmp_res= key_cmp(index_info->key_part, max_key,
+ real_prefix_len + min_max_arg_len);
+ if (!((cur_range->flag & NEAR_MAX) && (cmp_res == -1) ||
+ (cmp_res <= 0)))
+ {
+ result = HA_ERR_KEY_NOT_FOUND;
+ continue;
+ }
+ }
+ /* If we got to this point, the current key qualifies as MIN. */
+ DBUG_ASSERT(result == 0);
+ break;
+ }
+ /*
+ If there was a key with NULL in the MIN/MAX field, and there was no other
+ key without NULL from the same group that satisfies some other condition,
+ then use the key with the NULL.
+ */
+ if (found_null && result)
+ {
+ memcpy(record, tmp_record, head->rec_buff_length);
+ result= 0;
+ }
+ return result;
+}
+
+
+/*
+ Find the maximal key in a group that satisfies some range conditions for the
+ min/max argument field.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::next_max_in_range()
+
+ DESCRIPTION
+ Given the sequence of ranges min_max_ranges, find the maximal key that is
+ in the right-most possible range. If there is no such key, then the current
+ group does not have a MAX key that satisfies the WHERE clause. If a key is
+ found, its value is stored in this->record.
+
+ RETURN
+ 0 on success
+ HA_ERR_KEY_NOT_FOUND if there is no key with the given prefix in any of
+ the ranges
+ other if some error
+*/
+
+int QUICK_GROUP_MIN_MAX_SELECT::next_max_in_range()
+{
+ ha_rkey_function find_flag;
+ uint search_prefix_len;
+ QUICK_RANGE *cur_range;
+ int result;
+
+ DBUG_ASSERT(min_max_ranges.elements > 0);
+
+ for (uint range_idx= min_max_ranges.elements; range_idx > 0; range_idx--)
+ { /* Search from the right-most range to the left. */
+ get_dynamic(&min_max_ranges, (gptr)&cur_range, range_idx - 1);
+
+ /*
+ If the current value for the min/max argument is smaller than the left
+ boundary of cur_range, there is no need to check this range.
+ */
+ if (range_idx != min_max_ranges.elements &&
+ !(cur_range->flag & NO_MIN_RANGE) &&
+ (key_cmp(min_max_arg_part, cur_range->min_key, min_max_arg_len) == -1))
+ continue;
+
+ if (cur_range->flag & NO_MAX_RANGE)
+ {
+ find_flag= HA_READ_PREFIX_LAST;
+ search_prefix_len= real_prefix_len;
+ }
+ else
+ {
+ /* Extend the search key with the upper boundary for this range. */
+ memcpy(group_prefix + real_prefix_len, cur_range->max_key,
+ cur_range->max_length);
+ search_prefix_len= real_prefix_len + min_max_arg_len;
+ find_flag= (cur_range->flag & EQ_RANGE) ?
+ HA_READ_KEY_EXACT : (cur_range->flag & NEAR_MAX) ?
+ HA_READ_BEFORE_KEY : HA_READ_PREFIX_LAST_OR_PREV;
+ }
+
+ result= file->index_read(record, group_prefix, search_prefix_len,
+ find_flag);
+
+ if ((result == HA_ERR_KEY_NOT_FOUND) && (cur_range->flag & EQ_RANGE))
+ continue; /* Check the next range. */
+ else if (result)
+ /*
+ In no key was found with this upper bound, there certainly are no keys
+ in the ranges to the left.
+ */
+ return result;
+
+ /* A key was found. */
+ if (cur_range->flag & EQ_RANGE)
+ return result; /* No need to perform the checks below for equal keys. */
+
+ /* Check if record belongs to the current group. */
+ if (key_cmp(index_info->key_part, group_prefix, real_prefix_len))
+ {
+ result = HA_ERR_KEY_NOT_FOUND;
+ continue;
+ }
+
+ /* If there is a lower limit, check if the found key is in the range. */
+ if ( !(cur_range->flag & NO_MIN_RANGE) )
+ {
+ /* Compose the MIN key for the range. */
+ byte *min_key= (byte*) my_alloca(real_prefix_len + min_max_arg_len);
+ memcpy(min_key, group_prefix, real_prefix_len);
+ memcpy(min_key + real_prefix_len, cur_range->min_key,
+ cur_range->min_length);
+ /* Compare the found key with min_key. */
+ int cmp_res= key_cmp(index_info->key_part, min_key,
+ real_prefix_len + min_max_arg_len);
+ if (!((cur_range->flag & NEAR_MIN) && (cmp_res == 1) ||
+ (cmp_res >= 0)))
+ continue;
+ }
+ /* If we got to this point, the current key qualifies as MAX. */
+ return result;
+ }
+ return HA_ERR_KEY_NOT_FOUND;
+}
+
+
+/*
+ Update all MIN function results with the newly found value.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::update_min_result()
+
+ DESCRIPTION
+ The method iterates through all MIN functions and updates the result value
+ of each function by calling Item_sum::reset(), which in turn picks the new
+ result value from this->head->record[0], previously updated by
+ next_min(). The updated value is stored in a member variable of each of the
+ Item_sum objects, depending on the value type.
+
+ IMPLEMENTATION
+ The update must be done separately for MIN and MAX, immediately after
+ next_min() was called and before next_max() is called, because both MIN and
+ MAX take their result value from the same buffer this->head->record[0]
+ (i.e. this->record).
+
+ RETURN
+ None
+*/
+
+void QUICK_GROUP_MIN_MAX_SELECT::update_min_result()
+{
+ Item_sum *min_func;
+
+ min_functions_it->rewind();
+ while ((min_func= (*min_functions_it)++))
+ min_func->reset();
+}
+
+
+/*
+ Update all MAX function results with the newly found value.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::update_max_result()
+
+ DESCRIPTION
+ The method iterates through all MAX functions and updates the result value
+ of each function by calling Item_sum::reset(), which in turn picks the new
+ result value from this->head->record[0], previously updated by
+ next_max(). The updated value is stored in a member variable of each of the
+ Item_sum objects, depending on the value type.
+
+ IMPLEMENTATION
+ The update must be done separately for MIN and MAX, immediately after
+ next_max() was called, because both MIN and MAX take their result value
+ from the same buffer this->head->record[0] (i.e. this->record).
+
+ RETURN
+ None
+*/
+
+void QUICK_GROUP_MIN_MAX_SELECT::update_max_result()
+{
+ Item_sum *max_func;
+
+ max_functions_it->rewind();
+ while ((max_func= (*max_functions_it)++))
+ max_func->reset();
+}
+
+
+/*
+ Append comma-separated list of keys this quick select uses to key_names;
+ append comma-separated list of corresponding used lengths to used_lengths.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::add_keys_and_lengths()
+ key_names [out] Names of used indexes
+ used_lengths [out] Corresponding lengths of the index names
+
+ DESCRIPTION
+ This method is used by select_describe to extract the names of the
+ indexes used by a quick select.
+
+*/
+
+void QUICK_GROUP_MIN_MAX_SELECT::add_keys_and_lengths(String *key_names,
+ String *used_lengths)
+{
+ char buf[64];
+ uint length;
+ key_names->append(index_info->name);
+ length= longlong2str(max_used_key_length, buf, 10) - buf;
+ used_lengths->append(buf, length);
+}
+
+
+/*
+ Print quick select information to DBUG_FILE.
+
+ SYNOPSIS
+ QUICK_GROUP_MIN_MAX_SELECT::dbug_dump()
+ indent Indentation offset
+ verbose If TRUE show more detailed output.
+
+ DESCRIPTION
+ Print the contents of this quick select to DBUG_FILE. The method also
+ calls dbug_dump() for the used quick select if any.
+
+ IMPLEMENTATION
+ Caller is responsible for locking DBUG_FILE before this call and unlocking
+ it afterwards.
+
+ RETURN
+ None
+*/
+
+void QUICK_GROUP_MIN_MAX_SELECT::dbug_dump(int indent, bool verbose)
+{
+ fprintf(DBUG_FILE,
+ "%*squick_group_min_max_select: index %s (%d), length: %d\n",
+ indent, "", index_info->name, index, max_used_key_length);
+ if (key_infix_len > 0)
+ {
+ fprintf(DBUG_FILE, "%*susing key_infix with length %d:\n",
+ indent, "", key_infix_len);
+ }
+ if (quick_prefix_select)
+ {
+ fprintf(DBUG_FILE, "%*susing quick_range_select:\n", indent, "");
+ quick_prefix_select->dbug_dump(indent + 2, verbose);
+ }
+ if (min_max_ranges.elements > 0)
+ {
+ fprintf(DBUG_FILE, "%*susing %d quick_ranges for MIN/MAX:\n",
+ indent, "", min_max_ranges.elements);
+ }
+}
+
+
/*****************************************************************************
** Print a quick range for debugging
** TODO:
@@ -6260,7 +8369,7 @@ print_key(KEY_PART *key_part,const char *key,uint used_length)
static void print_quick(QUICK_SELECT_I *quick, const key_map *needed_reg)
{
char buf[MAX_KEY/8+1];
- DBUG_ENTER("print_param");
+ DBUG_ENTER("print_quick");
if (! _db_on_ || !quick)
DBUG_VOID_RETURN;
DBUG_LOCK_FILE;
diff --git a/sql/opt_range.h b/sql/opt_range.h
index 974ed409a87..19234f61ea2 100644
--- a/sql/opt_range.h
+++ b/sql/opt_range.h
@@ -146,7 +146,8 @@ public:
QS_TYPE_RANGE_DESC = 2,
QS_TYPE_FULLTEXT = 3,
QS_TYPE_ROR_INTERSECT = 4,
- QS_TYPE_ROR_UNION = 5
+ QS_TYPE_ROR_UNION = 5,
+ QS_TYPE_GROUP_MIN_MAX = 6
};
/* Get type of this quick select - one of the QS_TYPE_* values */
@@ -278,14 +279,12 @@ public:
int init();
int get_next();
void range_end();
-
+ int get_next_prefix(uint prefix_length, byte *cur_prefix);
bool reverse_sorted() { return 0; }
bool unique_key_range();
int init_ror_merged_scan(bool reuse_handler);
void save_last_pos()
- {
- file->position(record);
- };
+ { file->position(record); }
int get_type() { return QS_TYPE_RANGE; }
void add_keys_and_lengths(String *key_names, String *used_lengths);
void add_info_string(String *str);
@@ -518,6 +517,103 @@ private:
};
+/*
+ Index scan for GROUP-BY queries with MIN/MAX aggregate functions.
+
+ This class provides a specialized index access method for GROUP-BY queries
+ of the forms:
+
+ SELECT A_1,...,A_k, [B_1,...,B_m], [MIN(C)], [MAX(C)]
+ FROM T
+ WHERE [RNG(A_1,...,A_p ; where p <= k)]
+ [AND EQ(B_1,...,B_m)]
+ [AND PC(C)]
+ [AND PA(A_i1,...,A_iq)]
+ GROUP BY A_1,...,A_k;
+
+ or
+
+ SELECT DISTINCT A_i1,...,A_ik
+ FROM T
+ WHERE [RNG(A_1,...,A_p ; where p <= k)]
+ [AND PA(A_i1,...,A_iq)];
+
+ where all selected fields are parts of the same index.
+ The class of queries that can be processed by this quick select is fully
+ specified in the description of get_best_trp_group_min_max() in opt_range.cc.
+
+ The get_next() method directly produces result tuples, thus obviating the
+ need to call end_send_group() because all grouping is already done inside
+ get_next().
+
+ Since one of the requirements is that all select fields are part of the same
+ index, this class produces only index keys, and not complete records.
+*/
+
+class QUICK_GROUP_MIN_MAX_SELECT : public QUICK_SELECT_I
+{
+private:
+ handler *file; /* The handler used to get data. */
+ JOIN *join; /* Descriptor of the current query */
+ KEY *index_info; /* The index chosen for data access */
+ byte *record; /* Buffer where the next record is returned. */
+ byte *tmp_record; /* Temporary storage for next_min(), next_max(). */
+ byte *group_prefix; /* Key prefix consisting of the GROUP fields. */
+ uint group_prefix_len; /* Length of the group prefix. */
+ byte *last_prefix; /* Prefix of the last group for detecting EOF. */
+ bool have_min; /* Specify whether we are computing */
+ bool have_max; /* a MIN, a MAX, or both. */
+ bool seen_first_key; /* Denotes whether the first key was retrieved.*/
+ KEY_PART_INFO *min_max_arg_part; /* The keypart of the only argument field */
+ /* of all MIN/MAX functions. */
+ uint min_max_arg_len; /* The length of the MIN/MAX argument field */
+ byte *key_infix; /* Infix of constants from equality predicates. */
+ uint key_infix_len;
+ DYNAMIC_ARRAY min_max_ranges; /* Array of range ptrs for the MIN/MAX field. */
+ uint real_prefix_len; /* Length of key prefix extended with key_infix. */
+ List<Item_sum> *min_functions;
+ List<Item_sum> *max_functions;
+ List_iterator<Item_sum> *min_functions_it;
+ List_iterator<Item_sum> *max_functions_it;
+public:
+ /*
+ The following two members are public to allow easy access from
+ TRP_GROUP_MIN_MAX::make_quick()
+ */
+ MEM_ROOT alloc; /* Memory pool for this and quick_prefix_select data. */
+ QUICK_RANGE_SELECT *quick_prefix_select;/* For retrieval of group prefixes. */
+private:
+ int next_prefix();
+ int next_min_in_range();
+ int next_max_in_range();
+ int next_min();
+ int next_max();
+ void update_min_result();
+ void update_max_result();
+public:
+ QUICK_GROUP_MIN_MAX_SELECT(TABLE *table, JOIN *join, bool have_min,
+ bool have_max, KEY_PART_INFO *min_max_arg_part,
+ uint group_prefix_len, uint used_key_parts,
+ KEY *index_info, uint use_index, double read_cost,
+ ha_rows records, uint key_infix_len,
+ byte *key_infix, MEM_ROOT *parent_alloc);
+ ~QUICK_GROUP_MIN_MAX_SELECT();
+ bool add_range(SEL_ARG *sel_range);
+ void update_key_stat();
+ bool alloc_buffers();
+ int init();
+ int reset();
+ int get_next();
+ bool reverse_sorted() { return false; }
+ bool unique_key_range() { return false; }
+ int get_type() { return QS_TYPE_GROUP_MIN_MAX; }
+ void add_keys_and_lengths(String *key_names, String *used_lengths);
+#ifndef DBUG_OFF
+ void dbug_dump(int indent, bool verbose);
+#endif
+};
+
+
class QUICK_SELECT_DESC: public QUICK_RANGE_SELECT
{
public:
diff --git a/sql/opt_sum.cc b/sql/opt_sum.cc
index 314decb7041..2507b65111b 100644
--- a/sql/opt_sum.cc
+++ b/sql/opt_sum.cc
@@ -336,7 +336,7 @@ int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds)
1 Otherwise
*/
-static bool simple_pred(Item_func *func_item, Item **args, bool *inv_order)
+bool simple_pred(Item_func *func_item, Item **args, bool *inv_order)
{
Item *item;
*inv_order= 0;
diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index 51768922f6d..df615383ec3 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -1906,7 +1906,7 @@ GRANT_TABLE::GRANT_TABLE(TABLE *form, TABLE *col_privs)
col_privs->field[1]->pack_length()+
col_privs->field[2]->pack_length()+
col_privs->field[3]->pack_length());
- key_copy(key,col_privs,0,key_len);
+ key_copy(key,col_privs->record[0],col_privs->key_info,key_len);
col_privs->field[4]->store("",0, &my_charset_latin1);
col_privs->file->ha_index_init(0);
if (col_privs->file->index_read(col_privs->record[0],
@@ -2018,7 +2018,7 @@ static int replace_column_table(GRANT_TABLE *g_t,
table->field[3]->store(table_name,(uint) strlen(table_name), &my_charset_latin1);
key_length=(table->field[0]->pack_length()+ table->field[1]->pack_length()+
table->field[2]->pack_length()+ table->field[3]->pack_length());
- key_copy(key,table,0,key_length);
+ key_copy(key,table->record[0],table->key_info,key_length);
rights &= COL_ACLS; // Only ACL for columns
@@ -2031,7 +2031,7 @@ static int replace_column_table(GRANT_TABLE *g_t,
{
ulong privileges = xx->rights;
bool old_row_exists=0;
- key_restore(table,key,0,key_length);
+ key_restore(table->record[0],key,table->key_info,key_length);
table->field[4]->store(xx->column.ptr(),xx->column.length(),
&my_charset_latin1);
@@ -2047,7 +2047,7 @@ static int replace_column_table(GRANT_TABLE *g_t,
}
old_row_exists = 0;
restore_record(table,default_values); // Get empty record
- key_restore(table,key,0,key_length);
+ key_restore(table->record[0],key,table->key_info,key_length);
table->field[4]->store(xx->column.ptr(),xx->column.length(),
&my_charset_latin1);
}
diff --git a/sql/sql_handler.cc b/sql/sql_handler.cc
index 1443f9f9d5f..38bc4756f81 100644
--- a/sql/sql_handler.cc
+++ b/sql/sql_handler.cc
@@ -337,7 +337,7 @@ int mysql_ha_read(THD *thd, TABLE_LIST *tables,
send_error(thd,ER_OUTOFMEMORY);
goto err;
}
- key_copy(key, table, keyno, key_len);
+ key_copy(key, table->record[0], table->key_info + keyno, key_len);
err=table->file->index_read(table->record[0],
key,key_len,ha_rkey_mode);
mode=rkey_to_rnext[(int)ha_rkey_mode];
diff --git a/sql/sql_insert.cc b/sql/sql_insert.cc
index 787774e3236..36ac56799de 100644
--- a/sql/sql_insert.cc
+++ b/sql/sql_insert.cc
@@ -719,7 +719,7 @@ int write_record(THD *thd, TABLE *table,COPY_INFO *info)
goto err;
}
}
- key_copy((byte*) key,table,key_nr,0);
+ key_copy((byte*) key,table->record[0],table->key_info+key_nr,0);
if ((error=(table->file->index_read_idx(table->record[1],key_nr,
(byte*) key,
table->key_info[key_nr].
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index e104ac1ca38..ed65c8fd8fa 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -188,6 +188,7 @@ static bool update_sum_func(Item_sum **func);
static void select_describe(JOIN *join, bool need_tmp_table,bool need_order,
bool distinct, const char *message=NullS);
static Item *remove_additional_cond(Item* conds);
+static void add_group_and_distinct_keys(JOIN *join, JOIN_TAB *join_tab);
/*
@@ -624,7 +625,7 @@ JOIN::optimize()
conds=new Item_int((longlong) 1,1); // Always true
}
select=make_select(*table, const_table_map,
- const_table_map, conds, &error);
+ const_table_map, conds, &error, true);
if (error)
{ /* purecov: inspected */
error= -1; /* purecov: inspected */
@@ -1316,7 +1317,7 @@ JOIN::exec()
}
}
if (curr_join->make_sum_func_list(*curr_all_fields, *curr_fields_list,
- 1) ||
+ 1, TRUE) ||
(tmp_error= do_select(curr_join, (List<Item> *) 0, curr_tmp_table,
0)))
{
@@ -1404,7 +1405,7 @@ JOIN::exec()
set_items_ref_array(items3);
if (curr_join->make_sum_func_list(*curr_all_fields, *curr_fields_list,
- 1) || thd->is_fatal_error)
+ 1, TRUE) || thd->is_fatal_error)
DBUG_VOID_RETURN;
}
if (curr_join->group_list || curr_join->order)
@@ -2294,6 +2295,12 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
if (s->worst_seeks < 2.0) // Fix for small tables
s->worst_seeks=2.0;
+ /*
+ Add to stat->const_keys those indexes for which all group fields or
+ all select distinct fields participate in one index.
+ */
+ add_group_and_distinct_keys(join, s);
+
if (!s->const_keys.is_clear_all() &&
!s->table->pos_in_table_list->embedding)
{
@@ -2302,7 +2309,9 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
select= make_select(s->table, found_const_table_map,
found_const_table_map,
s->on_expr ? s->on_expr : conds,
- &error);
+ &error, true);
+ if (!select)
+ DBUG_RETURN(1);
records= get_quick_record_count(join->thd, select, s->table,
&s->const_keys, join->row_limit);
s->quick=select->quick;
@@ -2337,13 +2346,13 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
}
}
- /* Find best combination and return it */
join->join_tab=stat;
join->map2table=stat_ref;
join->table= join->all_tables=table_vector;
join->const_tables=const_count;
join->found_const_table_map=found_const_table_map;
+ /* Find an optimal join order of the non-constant tables. */
if (join->const_tables != join->tables)
{
optimize_keyuse(join, keyuse_array);
@@ -2355,6 +2364,7 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
sizeof(POSITION)*join->const_tables);
join->best_read=1.0;
}
+ /* Generate an execution plan from the found optimal join order. */
DBUG_RETURN(join->thd->killed || get_best_combination(join));
}
@@ -2551,6 +2561,10 @@ add_key_field(KEY_FIELD **key_fields,uint and_level, COND *cond,
bool is_const=1;
for (uint i=0; i<num_values; i++)
+ /*
+ TODO: This looks like a bug. It should be
+ is_const&= (value[i])->const_item();
+ */
is_const&= (*value)->const_item();
if (is_const)
stat[0].const_keys.merge(possible_keys);
@@ -2574,7 +2588,7 @@ add_key_field(KEY_FIELD **key_fields,uint and_level, COND *cond,
We can't use indexes if the effective collation
of the operation differ from the field collation.
- We can also not used index on a text column, as the column may
+ We also cannot use index on a text column, as the column may
contain 'x' 'x\t' 'x ' and 'read_next_same' will stop after
'x' when searching for WHERE col='x '
*/
@@ -2997,6 +3011,68 @@ static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array)
}
+/*
+ Discover the indexes that can be used for GROUP BY or DISTINCT queries.
+
+ SYNOPSIS
+ add_group_and_distinct_keys()
+ join
+ join_tab
+
+ DESCRIPTION
+ If the query has a GROUP BY clause, find all indexes that contain all
+ GROUP BY fields, and add those indexes to join->const_keys.
+ If the query has a DISTINCT clause, find all indexes that contain all
+ SELECT fields, and add those indexes to join->const_keys.
+ This allows later on such queries to be processed by a
+ QUICK_GROUP_MIN_MAX_SELECT.
+
+ RETURN
+ None
+*/
+
+static void
+add_group_and_distinct_keys(JOIN *join, JOIN_TAB *join_tab)
+{
+ List<Item_field> indexed_fields;
+ List_iterator<Item_field> indexed_fields_it(indexed_fields);
+ ORDER *cur_group;
+ Item_field *cur_item;
+ key_map possible_keys(0);
+
+ if (join->group_list)
+ { /* Collect all query fields referenced in the GROUP clause. */
+ for (cur_group= join->group_list; cur_group; cur_group= cur_group->next)
+ (*cur_group->item)->walk(&Item::collect_item_field_processor,
+ (byte*) &indexed_fields);
+ }
+ else if (join->select_distinct)
+ { /* Collect all query fields referenced in the SELECT clause. */
+ List<Item> &select_items= join->fields_list;
+ List_iterator<Item> select_items_it(select_items);
+ Item *item;
+ while ((item= select_items_it++))
+ item->walk(&Item::collect_item_field_processor, (byte*) &indexed_fields);
+ }
+ else
+ return;
+
+ if (indexed_fields.elements == 0)
+ return;
+
+ /* Intersect the keys of all group fields. */
+ cur_item= indexed_fields_it++;
+ possible_keys.merge(cur_item->field->part_of_key);
+ while ((cur_item= indexed_fields_it++))
+ {
+ possible_keys.intersect(cur_item->field->part_of_key);
+ }
+
+ if (!possible_keys.is_clear_all())
+ join_tab->const_keys.merge(possible_keys);
+}
+
+
/*****************************************************************************
Go through all combinations of not marked tables and find the one
which uses least records
@@ -4885,42 +4961,45 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
if (select)
{
table_map used_tables;
- if (join->tables > 1)
- cond->update_used_tables(); // Tablenr may have changed
- if (join->const_tables == join->tables &&
- join->thd->lex->current_select->master_unit() ==
- &join->thd->lex->unit) // not upper level SELECT
- join->const_table_map|=RAND_TABLE_BIT;
- { // Check const tables
- COND *const_cond=
- make_cond_for_table(cond,join->const_table_map,(table_map) 0);
- DBUG_EXECUTE("where",print_where(const_cond,"constants"););
- for (JOIN_TAB *tab= join->join_tab+join->const_tables;
- tab < join->join_tab+join->tables ; tab++)
- {
- if (tab->on_expr)
+ if (cond) /* Because of QUICK_GROUP_MIN_MAX_SELECT */
+ { /* there may be a select without a cond. */
+ if (join->tables > 1)
+ cond->update_used_tables(); // Tablenr may have changed
+ if (join->const_tables == join->tables &&
+ join->thd->lex->current_select->master_unit() ==
+ &join->thd->lex->unit) // not upper level SELECT
+ join->const_table_map|=RAND_TABLE_BIT;
+ { // Check const tables
+ COND *const_cond=
+ make_cond_for_table(cond,join->const_table_map,(table_map) 0);
+ DBUG_EXECUTE("where",print_where(const_cond,"constants"););
+ for (JOIN_TAB *tab= join->join_tab+join->const_tables;
+ tab < join->join_tab+join->tables ; tab++)
{
- JOIN_TAB *cond_tab= tab->first_inner;
- COND *tmp= make_cond_for_table(tab->on_expr,
- join->const_table_map,
- (table_map) 0);
- if (!tmp)
- continue;
- tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
- if (!tmp)
- DBUG_RETURN(1);
- tmp->quick_fix_field();
- cond_tab->select_cond= !cond_tab->select_cond ? tmp :
- new Item_cond_and(cond_tab->select_cond,tmp);
- if (!cond_tab->select_cond)
- DBUG_RETURN(1);
- cond_tab->select_cond->quick_fix_field();
- }
- }
- if (const_cond && !const_cond->val_int())
- {
- DBUG_PRINT("info",("Found impossible WHERE condition"));
- DBUG_RETURN(1); // Impossible const condition
+ if (tab->on_expr)
+ {
+ JOIN_TAB *cond_tab= tab->first_inner;
+ COND *tmp= make_cond_for_table(tab->on_expr,
+ join->const_table_map,
+ (table_map) 0);
+ if (!tmp)
+ continue;
+ tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
+ if (!tmp)
+ DBUG_RETURN(1);
+ tmp->quick_fix_field();
+ cond_tab->select_cond= !cond_tab->select_cond ? tmp :
+ new Item_cond_and(cond_tab->select_cond,tmp);
+ if (!cond_tab->select_cond)
+ DBUG_RETURN(1);
+ cond_tab->select_cond->quick_fix_field();
+ }
+ }
+ if (const_cond && !const_cond->val_int())
+ {
+ DBUG_PRINT("info",("Found impossible WHERE condition"));
+ DBUG_RETURN(1); // Impossible const condition
+ }
}
}
used_tables=((select->const_tables=join->const_table_map) |
@@ -4952,8 +5031,10 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
join->best_positions[i].records_read= rows2double(tab->quick->records);
}
- COND *tmp=make_cond_for_table(cond,used_tables,current_map);
- if (!tmp && tab->quick)
+ COND *tmp= NULL;
+ if (cond)
+ tmp= make_cond_for_table(cond,used_tables,current_map);
+ if (cond && !tmp && tab->quick)
{ // Outer join
if (tab->type != JT_ALL)
{
@@ -4976,7 +5057,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
}
}
- if (tmp)
+ if (tmp || !cond)
{
DBUG_EXECUTE("where",print_where(tmp,tab->table->table_name););
SQL_SELECT *sel=tab->select=(SQL_SELECT*)
@@ -4989,9 +5070,17 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
The guard will turn the predicate on only after
the first match for outer tables is encountered.
*/
- if (!(tmp= add_found_match_trig_cond(first_inner_tab, tmp, 0)))
- DBUG_RETURN(1);
- tab->select_cond=sel->cond=tmp;
+ if (cond)
+ {/*
+ Because of QUICK_GROUP_MIN_MAX_SELECT there may be a select without
+ a cond, so neutralize the hack above.
+ */
+ if (!(tmp= add_found_match_trig_cond(first_inner_tab, tmp, 0)))
+ DBUG_RETURN(1);
+ tab->select_cond=sel->cond=tmp;
+ }
+ else
+ tab->select_cond= sel->cond= NULL;
sel->head=tab->table;
if (tab->quick)
@@ -5031,7 +5120,8 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
the index if we are using limit and this is the first table
*/
- if ((!tab->keys.is_subset(tab->const_keys) && i > 0) ||
+ if (cond &&
+ (!tab->keys.is_subset(tab->const_keys) && i > 0) ||
(!tab->const_keys.is_clear_all() && i == join->const_tables &&
join->unit->select_limit_cnt <
join->best_positions[i].records_read &&
@@ -5089,7 +5179,8 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
}
if (i != join->const_tables && tab->use_quick != 2)
{ /* Read with cache */
- if ((tmp=make_cond_for_table(cond,
+ if (cond &&
+ (tmp=make_cond_for_table(cond,
join->const_table_map |
current_map,
current_map)))
@@ -7468,11 +7559,18 @@ do_select(JOIN *join,List<Item> *fields,TABLE *table,Procedure *procedure)
}
else
{
- if (join->sort_and_group || (join->procedure &&
- join->procedure->flags & PROC_GROUP))
- end_select=end_send_group;
+ /* Test if data is accessed via QUICK_GROUP_MIN_MAX_SELECT. */
+ bool is_using_quick_group_min_max_select=
+ (join->join_tab->select && join->join_tab->select->quick &&
+ (join->join_tab->select->quick->get_type() ==
+ QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX));
+
+ if ((join->sort_and_group ||
+ (join->procedure && join->procedure->flags & PROC_GROUP)) &&
+ !is_using_quick_group_min_max_select)
+ end_select= end_send_group;
else
- end_select=end_send;
+ end_select= end_send;
}
join->join_tab[join->tables-1].next_select=end_select;
@@ -9264,7 +9362,8 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
& HA_READ_PREV) ||
quick_type == QUICK_SELECT_I::QS_TYPE_INDEX_MERGE ||
quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT ||
- quick_type == QUICK_SELECT_I::QS_TYPE_ROR_UNION)
+ quick_type == QUICK_SELECT_I::QS_TYPE_ROR_UNION ||
+ quick_type == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX)
DBUG_RETURN(0); // Use filesort
/* ORDER BY range_key DESC */
@@ -10720,6 +10819,7 @@ bool JOIN::alloc_func_list()
field_list All items
send_fields Items in select list
before_group_by Set to 1 if this is called before GROUP BY handling
+ recompute Set to TRUE if sum_funcs must be recomputed
NOTES
Calls ::setup() for all item_sum objects in field_list
@@ -10730,13 +10830,16 @@ bool JOIN::alloc_func_list()
*/
bool JOIN::make_sum_func_list(List<Item> &field_list, List<Item> &send_fields,
- bool before_group_by)
+ bool before_group_by, bool recompute)
{
List_iterator_fast<Item> it(field_list);
Item_sum **func;
Item *item;
DBUG_ENTER("make_sum_func_list");
+ if (*sum_funcs && !recompute)
+ DBUG_RETURN(FALSE); /* We have already initialized sum_funcs. */
+
func= sum_funcs;
while ((item=it++))
{
@@ -11510,11 +11613,16 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
extra.append(tab->keys.print(buf));
extra.append(')');
}
- else
+ else if (tab->select->cond)
extra.append("; Using where");
}
if (key_read)
- extra.append("; Using index");
+ {
+ if (quick_type == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX)
+ extra.append("; Using index for group-by");
+ else
+ extra.append("; Using index");
+ }
if (table->reginfo.not_exists_optimize)
extra.append("; Not exists");
if (need_tmp_table)
diff --git a/sql/sql_select.h b/sql/sql_select.h
index eb80f3ee608..95b3b5e493e 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -303,7 +303,7 @@ class JOIN :public Sql_alloc
void restore_tmp();
bool alloc_func_list();
bool make_sum_func_list(List<Item> &all_fields, List<Item> &send_fields,
- bool before_group_by);
+ bool before_group_by, bool recompute= FALSE);
inline void set_items_ref_array(Item **ptr)
{
@@ -399,6 +399,7 @@ bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
uint find_shortest_key(TABLE *table, const key_map *usable_keys);
/* functions from opt_sum.cc */
+bool simple_pred(Item_func *func_item, Item **args, bool *inv_order);
int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds);
/* from sql_delete.cc, used by opt_range.cc */
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