CLIENT_MULTI_QUERIES -> CLIENT_MULTI_STATEMENTS

New multi-key-cache handling. This was needed becasue the old one didn't work reliable with MERGE tables.
ALTER TABLE table_name ... CHARACTER SET  ... now changes all char/varchar/text columns to the given character set
(One must use ALTER TABLE ... DEFAULT CHARACTER SET ... to change the default character set)
Fixed that have_compress is detected properly (fixes problems with func_compress.test on platforms without zlib)
New syntax for CACHE INDEX ('keys' is optional if no index name is given and one mentions the key cache name only ones)
Removed compiler warnings
Added mysql_set_server_option() to allow clients like PHP to easaily set/reset the multi-statement flag.

1 files changed, 359 insertions, 0 deletions

diff --git a/mysys/mf_keycaches.c b/mysys/mf_keycaches.c
new file mode 100644
index 00000000000..1d770e17719
--- /dev/null
+++ b/mysys/mf_keycaches.c
@@ -0,0 +1,359 @@
+/* Copyright (C) 2003 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+/*
+  Handling of multiple key caches
+
+  The idea is to have a thread safe hash on the table name,
+  with a default key cache value that is returned if the table name is not in
+  the cache.
+*/
+
+#include "mysys_priv.h"
+#include <hash.h>
+#include <m_string.h>
+
+/*****************************************************************************
+  General functions to handle SAFE_HASH objects.
+
+  A SAFE_HASH object is used to store the hash, the mutex and default value
+  needed by the rest of the key cache code.
+  This is a separate struct to make it easy to later reuse the code for other
+  purposes
+
+  All entries are linked in a list to allow us to traverse all elements
+  and delete selected ones. (HASH doesn't allow any easy ways to do this).
+*****************************************************************************/
+
+/*
+  Struct to store a key and pointer to object
+*/
+
+typedef struct st_safe_hash_entry
+{
+  byte *key;
+  uint length;
+  byte *data;
+  struct st_safe_hash_entry *next, **prev;
+} SAFE_HASH_ENTRY;
+
+
+typedef struct st_safe_hash_with_default
+{
+#ifdef THREAD
+  rw_lock_t mutex;
+#endif
+  HASH hash;
+  byte *default_value;
+  SAFE_HASH_ENTRY *root;
+} SAFE_HASH;
+
+
+/*
+  Free a SAFE_HASH_ENTRY
+
+  This function is called by the hash object on delete
+*/
+
+static void safe_hash_entry_free(SAFE_HASH_ENTRY *entry)
+{
+  DBUG_ENTER("free_assign_entry");
+  my_free((gptr) entry, MYF(0));
+  DBUG_VOID_RETURN;
+}
+
+
+/* Get key and length for a SAFE_HASH_ENTRY */
+
+static byte *safe_hash_entry_get(SAFE_HASH_ENTRY *entry, uint *length,
+				 my_bool not_used __attribute__((unused)))
+{
+  *length=entry->length;
+  return (byte*) entry->key;
+}
+
+
+/*
+  Init a SAFE_HASH object
+
+  SYNOPSIS
+    safe_hash_init()
+    hash		safe_hash handler
+    elements		Expected max number of elements
+    default_value	default value
+
+  NOTES
+    In case of error we set hash->default_value to 0 to allow one to call
+    safe_hash_free on an object that couldn't be initialized.
+
+  RETURN
+    0  ok
+    1  error
+*/
+
+static my_bool safe_hash_init(SAFE_HASH *hash, uint elements,
+			      byte *default_value)
+{
+  DBUG_ENTER("safe_hash");
+  if (hash_init(&hash->hash, &my_charset_bin, elements,
+		0, 0, (hash_get_key) safe_hash_entry_get,
+		(void (*)(void*)) safe_hash_entry_free, 0))
+  {
+    hash->default_value= 0;
+    DBUG_RETURN(1);
+  }
+  my_rwlock_init(&hash->mutex, 0);
+  hash->default_value= default_value;
+  hash->root= 0;
+  DBUG_RETURN(0);
+}
+
+
+/*
+  Free a SAFE_HASH object
+
+  NOTES
+    This is safe to call on any object that has been sent to safe_hash_init()
+*/
+
+static void safe_hash_free(SAFE_HASH *hash)
+{
+  /*
+    Test if safe_hash_init succeeded. This will also guard us against multiple
+    free calls.
+  */
+  if (hash->default_value)
+  {
+    hash_free(&hash->hash);
+    rwlock_destroy(&hash->mutex);
+    hash->default_value=0;
+  }
+}
+
+/*
+  Return the value stored for a key or default value if no key
+*/
+
+static byte *safe_hash_search(SAFE_HASH *hash, const byte *key, uint length)
+{
+  byte *result;
+  DBUG_ENTER("safe_hash_search");
+  rw_rdlock(&hash->mutex);
+  result= hash_search(&hash->hash, key, length);
+  rw_unlock(&hash->mutex);
+  if (!result)
+    result= hash->default_value;
+  else
+    result= ((SAFE_HASH_ENTRY*) result)->data;
+  DBUG_PRINT("exit",("data: %lx", result));
+  DBUG_RETURN(result);
+}
+
+
+/*
+  Associate a key with some data
+
+  SYONOPSIS
+    safe_hash_set()
+    hash			Hash handle
+    key				key (path to table etc..)
+    length			Length of key
+    data			data to to associate with the data
+
+  NOTES
+    This can be used both to insert a new entry and change an existing
+    entry.
+    If one associates a key with the default key cache, the key is deleted
+
+  RETURN
+    0  ok
+    1  error (Can only be EOM). In this case my_message() is called.
+*/
+
+static my_bool safe_hash_set(SAFE_HASH *hash, const byte *key, uint length,
+			     byte *data)
+{
+  SAFE_HASH_ENTRY *entry;
+  my_bool error= 0;
+  DBUG_ENTER("safe_hash_set");
+  DBUG_PRINT("enter",("key: %.*s  data: %lx", length, key, data));
+
+  rw_wrlock(&hash->mutex);
+  entry= (SAFE_HASH_ENTRY*) hash_search(&hash->hash, key, length);
+
+  if (data == hash->default_value)
+  {
+    /*
+      The key is to be associated with the default entry. In this case
+      we can just delete the entry (if it existed) from the hash as a
+      search will return the default entry
+    */
+    if (!entry)					/* nothing to do */
+      goto end;
+    /* unlink entry from list */
+    if ((*entry->prev= entry->next))
+      entry->next->prev= entry->prev;
+    hash_delete(&hash->hash, (byte*) entry);
+    goto end;
+  }
+  if (entry)
+  {
+    /* Entry existed;  Just change the pointer to point at the new data */
+    entry->data= data;
+  }
+  else
+  {
+    if (!(entry= (SAFE_HASH_ENTRY *) my_malloc(sizeof(*entry) + length,
+					       MYF(MY_WME))))
+    {
+      error= 1;
+      goto end;
+    }
+    entry->key= (byte*) (entry +1);
+    memcpy((char*) entry->key, (char*) key, length);
+    entry->length= length;
+    entry->data= data;
+    /* Link entry to list */
+    if ((entry->next= hash->root))
+      entry->next->prev= &entry->next;
+    entry->prev= &hash->root;
+    hash->root= entry;
+    if (my_hash_insert(&hash->hash, (byte*) entry))
+    {
+      /* This can only happen if hash got out of memory */
+      my_delete((char*) entry, MYF(0));
+      error= 1;
+      goto end;
+    }
+  }
+
+end:
+  rw_unlock(&hash->mutex);
+  DBUG_RETURN(error);
+}
+
+
+/*
+  Change all entres with one data value to another data value
+
+  SYONOPSIS
+    safe_hash_change()
+    hash			Hash handle
+    old_data			Old data
+    new_data			Change all 'old_data' to this
+
+  NOTES
+    We use the linked list to traverse all elements in the hash as
+    this allows us to delete elements in the case where 'new_data' is the
+    default value.
+*/
+
+static void safe_hash_change(SAFE_HASH *hash, byte *old_data, byte *new_data)
+{
+  SAFE_HASH_ENTRY *entry, *next;
+  DBUG_ENTER("safe_hash_set");
+
+  rw_wrlock(&hash->mutex);
+
+  for (entry= hash->root ; entry ; entry= next)
+  {
+    next= entry->next;
+    if (entry->data == old_data)
+    {
+      if (new_data == hash->default_value)
+	hash_delete(&hash->hash, (byte*) entry);
+      else
+	entry->data= new_data;
+    }
+  }
+
+  rw_unlock(&hash->mutex);
+  DBUG_VOID_RETURN;
+}
+
+
+/*****************************************************************************
+  Functions to handle the key cache objects
+*****************************************************************************/
+
+/* Variable to store all key cache objects */
+static SAFE_HASH key_cache_hash;
+
+
+my_bool multi_keycache_init(void)
+{
+  return safe_hash_init(&key_cache_hash, 16, (byte*) dflt_keycache);
+}
+
+
+void multi_keycache_free(void)
+{
+  safe_hash_free(&key_cache_hash);
+}
+
+/*
+  Get a key cache to be used for a specific table.
+
+  SYNOPSIS
+    multi_key_cache_get()
+    key				key to find (usually table path)
+    uint length			Length of key.
+
+  NOTES
+    This function is coded in such a way that we will return the
+    default key cache even if one never called multi_keycache_init.
+    This will ensure that it works with old MyISAM clients.
+
+  RETURN
+    key cache to use
+*/
+
+KEY_CACHE_HANDLE *multi_key_cache_search(byte *key, uint length)
+{
+  if (!key_cache_hash.hash.records)
+    return dflt_keycache;
+  return (KEY_CACHE_HANDLE*) safe_hash_search(&key_cache_hash, key, length);
+}
+
+
+/*
+  Assosiate a key cache with a key
+
+
+  SYONOPSIS
+    multi_key_cache_set()
+    key				key (path to table etc..)
+    length			Length of key
+    key_cache			cache to assococite with the table
+
+  NOTES
+    This can be used both to insert a new entry and change an existing
+    entry
+*/
+
+
+my_bool multi_key_cache_set(const byte *key, uint length,
+			    KEY_CACHE_HANDLE *key_cache)
+{
+  return safe_hash_set(&key_cache_hash, key, length, (byte*) key_cache);
+}
+
+
+void multi_key_cache_change(KEY_CACHE_HANDLE *old_data,
+			    KEY_CACHE_HANDLE *new_data)
+{
+  safe_hash_change(&key_cache_hash, (byte*) old_data, (byte*) new_data);
+}