mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2026-05-16 11:57:38 +02:00
Code Issues Projects Releases Packages Wiki Activity

BUG#17314: Can't use index_merge/intersection for MERGE tables

Browse source 
1. Fix index access costs for MERGE tables, set block_size=myisam_block_size/#underlying_tables 
   instead of 0 which it was before.
2. Make index scans on MERGE table to return records in (key_tuple, merge_table_rowid) order, 
   instead of just (key_tuple) order. This makes an index scan on MERGE table to be truly a ROR-scan
   which is a requirement for index_merge union/intersection.
This commit is contained in:
sergefp@mysql.com 2006-02-11 21:51:43 +03:00
commit f95b5b0a5d
5 changed files with 87 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

20
myisammrg/myrg_queue.c
View file

@ -18,12 +18,26 @@
static int queue_key_cmp(void *keyseg, byte *a, byte *b)
{
MI_INFO *aa=((MYRG_TABLE *)a)->table;
MI_INFO *bb=((MYRG_TABLE *)b)->table;
MYRG_TABLE *ma= (MYRG_TABLE *)a;
MYRG_TABLE *mb= (MYRG_TABLE *)b;
MI_INFO *aa= ma->table;
MI_INFO *bb= mb->table;
uint not_used[2];
int ret= ha_key_cmp((HA_KEYSEG *)keyseg, aa->lastkey, bb->lastkey,
USE_WHOLE_KEY, SEARCH_FIND, not_used);
return ret < 0 ? -1 : ret > 0 ? 1 : 0;
if (ret < 0)
return -1;
if (ret > 0)
return 1;
/*
If index tuples have the same values, let the record with least rowid
value be "smaller", so index scans return records ordered by (keytuple,
rowid). This is used by index_merge access method, grep for ROR in
sql/opt_range.cc for details.
*/
return (ma->file_offset < mb->file_offset)? -1 : (ma->file_offset >
mb->file_offset) ? 1 : 0;
} /* queue_key_cmp */