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Bug#9112 - Merge table with composite index producing invalid results with some queries

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The problem was an ab-use of last_rkey_length.
Formerly we saved the packed key length (of the search key)
in this element. But in certain cases it got replaced by 
the (packed) result key length.
Now we use a new element of MI_INFO to save the packed key 
length of the search key.


myisam/mi_dbug.c:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Fixed the recognition of NULL values in _mi_print_key().
myisam/mi_rkey.c:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Saved the packed key length in a new element of MI_INFO.
myisam/mi_search.c:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Added a comment and trace prints.
myisam/myisamdef.h:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Added a new element to store the packed key length
  for use by the MyISAMMRG engine.
myisammrg/myrg_rkey.c:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Changed to use the new element of MI_INFO to get at the
  packed key length.
mysql-test/r/merge.result:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  The test result.
mysql-test/t/merge.test:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  The test case.
This commit is contained in:
unknown
2005-09-23 10:15:11 +02:00
parent a89807336f
commit 674c8165ea
7 changed files with 92 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
myisam/mi_dbug.c
View File

@ -40,12 +40,12 @@ void _mi_print_key(FILE *stream, register MI_KEYSEG *keyseg,
end= key+ keyseg->length;
if (keyseg->flag & HA_NULL_PART)
{
if (!*key)
/* A NULL value is encoded by a 1-byte flag. Zero means NULL. */
if (! *(key++))
{
fprintf(stream,"NULL");
continue;
}
key++;
}
switch (keyseg->type) {

7
myisam/mi_rkey.c
View File

@ -31,8 +31,8 @@ int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len,
MI_KEYSEG *last_used_keyseg;
uint pack_key_length, use_key_length, nextflag;
DBUG_ENTER("mi_rkey");
DBUG_PRINT("enter",("base: %lx inx: %d search_flag: %d",
info,inx,search_flag));
DBUG_PRINT("enter", ("base: %p buf: %p inx: %d search_flag: %d",
info, buf, inx, search_flag));
if ((inx = _mi_check_index(info,inx)) < 0)
DBUG_RETURN(my_errno);
@ -44,9 +44,12 @@ int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len,
{
if (key_len == 0)
key_len=USE_WHOLE_KEY;
/* Save the packed key for later use in the second buffer of lastkey. */
key_buff=info->lastkey+info->s->base.max_key_length;
pack_key_length=_mi_pack_key(info, (uint) inx, key_buff, (uchar*) key,
key_len, &last_used_keyseg);
/* Save packed_key_length for use by the MERGE engine. */
info->pack_key_length= pack_key_length;
DBUG_EXECUTE("key",_mi_print_key(DBUG_FILE, keyinfo->seg,
key_buff, pack_key_length););
}

16
myisam/mi_search.c
View File

@ -1237,11 +1237,21 @@ uint _mi_get_binary_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag,
reg1 MI_KEYSEG *keyseg;
uchar *start_key,*page,*page_end,*from,*from_end;
uint length,tmp;
DBUG_ENTER("_mi_get_binary_pack_key");
page= *page_pos;
page_end=page+MI_MAX_KEY_BUFF+1;
start_key=key;
/*
Keys are compressed the following way:
prefix length Packed length of prefix for the prev key. (1 or 3 bytes)
for each key segment:
[is null] Null indicator if can be null (1 byte, zero means null)
[length] Packed length if varlength (1 or 3 bytes)
pointer Reference to the data file (last_keyseg->length).
*/
get_key_length(length,page);
if (length)
{
@ -1251,7 +1261,7 @@ uint _mi_get_binary_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag,
length, keyinfo->maxlength, *page_pos));
DBUG_DUMP("key",(char*) *page_pos,16);
my_errno=HA_ERR_CRASHED;
return 0; /* Wrong key */
DBUG_RETURN(0); /* Wrong key */
}
from=key; from_end=key+length;
}
@ -1312,12 +1322,12 @@ uint _mi_get_binary_pack_key(register MI_KEYDEF *keyinfo, uint nod_flag,
{
DBUG_PRINT("error",("Error when unpacking key"));
my_errno=HA_ERR_CRASHED;
return 0; /* Error */
DBUG_RETURN(0); /* Error */
}
memcpy((byte*) key,(byte*) from,(size_t) length);
*page_pos= from+length;
}
return((uint) (key-start_key)+keyseg->length);
DBUG_RETURN((uint) (key-start_key)+keyseg->length);
}

1
myisam/myisamdef.h
View File

@ -255,6 +255,7 @@ struct st_myisam_info {
uint lastkey_length; /* Length of key in lastkey */
uint last_rkey_length; /* Last length in mi_rkey() */
uint save_lastkey_length;
uint pack_key_length; /* For MYISAMMRG */
int errkey; /* Got last error on this key */
int lock_type; /* How database was locked */
int tmp_lock_type; /* When locked by readinfo */

17
myisammrg/myrg_rkey.c
View File

@ -44,11 +44,12 @@ int myrg_rkey(MYRG_INFO *info,byte *buf,int inx, const byte *key,
MYRG_TABLE *table;
MI_INFO *mi;
int err;
DBUG_ENTER("myrg_rkey");
LINT_INIT(key_buff);
LINT_INIT(pack_key_length);
if (_myrg_init_queue(info,inx,search_flag))
return my_errno;
DBUG_RETURN(my_errno);
for (table=info->open_tables ; table != info->end_table ; table++)
{
@ -57,8 +58,9 @@ int myrg_rkey(MYRG_INFO *info,byte *buf,int inx, const byte *key,
if (table == info->open_tables)
{
err=mi_rkey(mi,0,inx,key,key_len,search_flag);
/* Get the saved packed key and packed key length. */
key_buff=(byte*) mi->lastkey+mi->s->base.max_key_length;
pack_key_length=mi->last_rkey_length;
pack_key_length=mi->pack_key_length;
}
else
{
@ -72,16 +74,21 @@ int myrg_rkey(MYRG_INFO *info,byte *buf,int inx, const byte *key,
{
if (err == HA_ERR_KEY_NOT_FOUND)
continue;
return err;
DBUG_PRINT("exit", ("err: %d", err));
DBUG_RETURN(err);
}
/* adding to queue */
queue_insert(&(info->by_key),(byte *)table);
}
DBUG_PRINT("info", ("tables with matches: %u", info->by_key.elements));
if (!info->by_key.elements)
return HA_ERR_KEY_NOT_FOUND;
DBUG_RETURN(HA_ERR_KEY_NOT_FOUND);
mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table;
return _myrg_mi_read_record(mi,buf);
DBUG_PRINT("info", ("using table no: %d",
info->current_table - info->open_tables + 1));
DBUG_DUMP("result key", (byte*) mi->lastkey, mi->lastkey_length);
DBUG_RETURN(_myrg_mi_read_record(mi,buf));
}

26
mysql-test/r/merge.result
View File

@ -619,3 +619,29 @@ INSERT TABLE 't1' isn't allowed in FROM table list
create table t3 engine=merge union=(t1, t2) select * from t2;
INSERT TABLE 't2' isn't allowed in FROM table list
drop table t1, t2;
create table t1 (
a double(16,6),
b varchar(10),
index (a,b)
) engine=merge union=(t2,t3);
create table t2 (
a double(16,6),
b varchar(10),
index (a,b)
) engine=myisam;
create table t3 (
a double(16,6),
b varchar(10),
index (a,b)
) engine=myisam;
insert into t2 values ( null, '');
insert into t2 values ( 9999999999.999999, '');
insert into t3 select * from t2;
select min(a), max(a) from t1;
min(a) max(a)
9999999999.999998 9999999999.999998
flush tables;
select min(a), max(a) from t1;
min(a) max(a)
9999999999.999998 9999999999.999998
drop table t1, t2, t3;

33
mysql-test/t/merge.test
View File

@ -264,3 +264,36 @@ create table t3 engine=merge union=(t1, t2) select * from t1;
--error 1093
create table t3 engine=merge union=(t1, t2) select * from t2;
drop table t1, t2;
#
# Bug#9112 - Merge table with composite index producing invalid results with some queries
# This test case will fail only without the bugfix and some
# non-deterministic circumstances. It depends on properly initialized
# "un-initialized" memory. At the time it happens with a standard
# non-debug build. But there is no guarantee that this will be always so.
#
create table t1 (
a double(16,6),
b varchar(10),
index (a,b)
) engine=merge union=(t2,t3);
create table t2 (
a double(16,6),
b varchar(10),
index (a,b)
) engine=myisam;
create table t3 (
a double(16,6),
b varchar(10),
index (a,b)
) engine=myisam;
insert into t2 values ( null, '');
insert into t2 values ( 9999999999.999999, '');
insert into t3 select * from t2;
select min(a), max(a) from t1;
flush tables;
select min(a), max(a) from t1;
drop table t1, t2, t3;