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| author | unknown <ingo@mysql.com> | 2006-03-10 15:03:04 +0100 |
|---|---|---|
| committer | unknown <ingo@mysql.com> | 2006-03-10 15:03:04 +0100 |
| commit | fbe17c2a36dcaa99c5a6570f7096745126113301 (patch) | |
| tree | 801bfa5ba08dc20436d5731d021e7d7e7cf2f4e5 /include | |
| parent | a7abbd918ba952e2f387cec28ed0f74997b14975 (diff) | |
| download | mariadb-git-fbe17c2a36dcaa99c5a6570f7096745126113301.tar.gz | |
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
For "count(*) while index_column = value" an index read
is done. It consists of an index scan and retrieval of
each key.
For efficiency reasons the index scan stores the key in
the special buffer 'lastkey2' once only. At the first
iteration it notes this fact with the flag
HA_STATE_RNEXT_SAME in 'info->update'.
For efficiency reasons, the key retrieval for blobs
does not allocate a new buffer, but uses 'lastkey2'...
Now I clear the HA_STATE_RNEXT_SAME flag whenever the
buffer has been polluted. In this case, the index scan
copies the key value again (and sets the flag again).
include/my_base.h:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Changed the comment for HA_STATE_RNEXT_SAME as a warning
for future uses.
myisam/mi_delete.c:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Removing the flag HA_STATE_RNEXT_SAME from info->update
if info->lastkey2 was reused for another purpose than
index scanning.
myisam/mi_key.c:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Removing the flag HA_STATE_RNEXT_SAME from info->update
if info->lastkey2 was reused for another purpose than
index scanning.
myisam/mi_rnext_same.c:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Removed trailing space and fixed a comment.
myisam/mi_unique.c:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Removing the flag HA_STATE_RNEXT_SAME from info->update
if info->lastkey2 was reused for another purpose than
index scanning.
myisam/mi_update.c:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Removing the flag HA_STATE_RNEXT_SAME from info->update
if info->lastkey2 was reused for another purpose than
index scanning.
myisam/mi_write.c:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Removing the flag HA_STATE_RNEXT_SAME from info->update
if info->lastkey2 was reused for another purpose than
index scanning.
mysql-test/r/myisam.result:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Added test result.
mysql-test/t/myisam.test:
Bug#14980 - COUNT(*) incorrect on MyISAM table with certain INDEX
Added test.
Diffstat (limited to 'include')
| -rw-r--r-- | include/my_base.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/my_base.h b/include/my_base.h index 271e7cd23ba..1261a95175f 100644 --- a/include/my_base.h +++ b/include/my_base.h @@ -340,7 +340,7 @@ enum ha_base_keytype { #define HA_STATE_BUFF_SAVED 512 /* If current keybuff is info->buff */ #define HA_STATE_ROW_CHANGED 1024 /* To invalide ROW cache */ #define HA_STATE_EXTEND_BLOCK 2048 -#define HA_STATE_RNEXT_SAME 4096 /* rnext_same was called */ +#define HA_STATE_RNEXT_SAME 4096 /* rnext_same occupied lastkey2 */ enum en_fieldtype { FIELD_LAST=-1,FIELD_NORMAL,FIELD_SKIP_ENDSPACE,FIELD_SKIP_PRESPACE, |