diff options
Diffstat (limited to 'myisam/mi_search.c')
| -rw-r--r-- | myisam/mi_search.c | 123 |
1 files changed, 81 insertions, 42 deletions
diff --git a/myisam/mi_search.c b/myisam/mi_search.c index 2871633102d..73a4d229fd6 100644 --- a/myisam/mi_search.c +++ b/myisam/mi_search.c @@ -273,7 +273,8 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page, uchar *sort_order=keyinfo->seg->charset->sort_order; uchar tt_buff[MI_MAX_KEY_BUFF+2], *t_buff=tt_buff+2; uchar *saved_from, *saved_to, *saved_vseg; - uint saved_length=0, saved_prefix_len=0; + uint saved_length=0, saved_prefix_len=0; + uint length_pack; DBUG_ENTER("_mi_prefix_search"); LINT_INIT(length); @@ -289,26 +290,24 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page, page+=2+nod_flag; *ret_pos=page; kseg=key; - { - uint lenght_pack; - get_key_pack_length(kseg_len,lenght_pack,kseg); - key_len_skip=lenght_pack+kseg_len; - key_len_left=(int) key_len- (int) key_len_skip; - cmplen=(key_len_left>=0) ? kseg_len : key_len-lenght_pack; - DBUG_PRINT("info",("key: '%.*s'",kseg_len,kseg)); - } -/* - Keys are compressed the following way: + get_key_pack_length(kseg_len,length_pack,kseg); + key_len_skip=length_pack+kseg_len; + key_len_left=(int) key_len- (int) key_len_skip; + cmplen=(key_len_left>=0) ? kseg_len : key_len-length_pack; + DBUG_PRINT("info",("key: '%.*s'",kseg_len,kseg)); - If the max length of first key segment <= 127 characters the prefix is - 1 byte else it's 2 byte + /* + Keys are compressed the following way: - prefix The high bit is set if this is a prefix for the prev key - length Packed length if the previous was a prefix byte - [length] Length character of data - next-key-seg Next key segments -*/ + If the max length of first key segment <= 127 characters the prefix is + 1 byte else it's 2 byte + + prefix The high bit is set if this is a prefix for the prev key + length Packed length if the previous was a prefix byte + [length] Length character of data + next-key-seg Next key segments + */ matched=0; /* how many char's from prefix were alredy matched */ len=0; /* length of previous key unpacked */ @@ -350,7 +349,8 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page, saved_vseg=vseg; saved_prefix_len=prefix_len; - DBUG_PRINT("loop",("page: '%.*s%.*s'",prefix_len,t_buff+seg_len_pack,suffix_len,vseg)); + DBUG_PRINT("loop",("page: '%.*s%.*s'",prefix_len,t_buff+seg_len_pack, + suffix_len,vseg)); { uchar *from=vseg+suffix_len; HA_KEYSEG *keyseg; @@ -396,14 +396,15 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page, matched=prefix_len+left; - for(my_flag=0;left;left--) + for (my_flag=0;left;left--) if ((my_flag= (int) sort_order[*vseg++] - (int) sort_order[*k++])) break; if (my_flag>0) /* mismatch */ break; - else if (my_flag==0) /* match */ - { /* + if (my_flag==0) /* match */ + { + /* ** len cmplen seg_left_len more_segs ** < matched=len; continue search ** > = prefix ? found : (matched=len; continue search) @@ -414,30 +415,68 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page, */ if (len < cmplen) { - my_flag= -1; + if ((keyinfo->seg->type != HA_KEYTYPE_TEXT && + keyinfo->seg->type != HA_KEYTYPE_VARTEXT)) + my_flag= -1; + else + { + /* We have to compare k and vseg as if they where space extended */ + uchar *end= k+ (cmplen - len); + for ( ; k < end && *k == ' '; k++) ; + if (k == end) + goto cmp_rest; /* should never happen */ + if (*k < (uchar) ' ') + { + my_flag= 1; /* Compared string is smaller */ + break; + } + my_flag= -1; /* Continue searching */ + } } else if (len > cmplen) { - if ((my_flag= (!(nextflag & SEARCH_PREFIX) || key_len_left>0))) - break; - goto fix_flag; - } - else if (key_len_left>0) - { - uint not_used; - if ((flag = ha_key_cmp(keyinfo->seg+1,vseg, - k,key_len_left,nextflag,¬_used)) >= 0) - break; + uchar *end; + if ((nextflag & SEARCH_PREFIX) && key_len_left == 0) + goto fix_flag; + + /* We have to compare k and vseg as if they where space extended */ + for (end=vseg + (len-cmplen) ; + vseg < end && *vseg == (uchar) ' '; + vseg++) ; + if (vseg == end) + goto cmp_rest; /* should never happen */ + + if (*vseg > (uchar) ' ') + { + my_flag= 1; /* Compared string is smaller */ + break; + } + my_flag= -1; /* Continue searching */ } else - { - /* at this line flag==-1 if the following lines were already - visited and 0 otherwise, i.e. flag <=0 here always !!! */ - fix_flag: - if (nextflag & (SEARCH_NO_FIND | SEARCH_LAST)) - flag=(nextflag & (SEARCH_BIGGER | SEARCH_LAST)) ? -1 : 1; - if (flag>=0) break; - } + { + cmp_rest: + if (key_len_left>0) + { + uint not_used; + if ((flag = ha_key_cmp(keyinfo->seg+1,vseg, + k,key_len_left,nextflag,¬_used)) >= 0) + break; + } + else + { + /* + at this line flag==-1 if the following lines were already + visited and 0 otherwise, i.e. flag <=0 here always !!! + */ + fix_flag: + DBUG_ASSERT(flag <= 0); + if (nextflag & (SEARCH_NO_FIND | SEARCH_LAST)) + flag=(nextflag & (SEARCH_BIGGER | SEARCH_LAST)) ? -1 : 1; + if (flag>=0) + break; + } + } } matched-=left; } @@ -1567,7 +1606,7 @@ _mi_calc_var_pack_key_length(MI_KEYDEF *keyinfo,uint nod_flag,uchar *next_key, n_length-=tmp_length; length-=tmp_length+next_length_pack; /* We gained these chars */ } - if (n_length == 0) + if (n_length == 0 && ref_length == new_key_length) { s_temp->n_ref_length=pack_marker; /* Same as prev key */ } |