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4.1 repository of svoj. When svoj does a push these changes will
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ChangeSet@stripped, 2006-12-01 20:13:18+04:00, svoj@stripped +6 -0
BUG#21310 - Trees in SQL causing a "crashed" table with MyISAM storage engine
An update that used a join of a table to itself and modified the
table on one side of the join reported the table as crashed or
updated wrong rows.
Fixed by creating temporary table for self-joined multi update statement.
mysql-test/r/myisam.result@stripped, 2006-12-01 20:13:16+04:00, svoj@stripped +16 -0
A test case for BUG#21310.
mysql-test/t/myisam.test@stripped, 2006-12-01 20:13:16+04:00, svoj@stripped +19 -0
A test case for BUG#21310.
sql/lock.cc@stripped, 2006-12-01 20:13:16+04:00, svoj@stripped +5 -1
Added for_update argument, that instruct mysql_lock_have_duplicate to
exclude 'table' from check.
sql/mysql_priv.h@stripped, 2006-12-01 20:13:16+04:00, svoj@stripped +2 -1
Updated mysql_lock_have_duplicate declaration.
sql/sql_parse.cc@stripped, 2006-12-01 20:13:16+04:00, svoj@stripped +1 -1
Updated mysql_lock_have_duplicate call.
sql/sql_update.cc@stripped, 2006-12-01 20:13:16+04:00, svoj@stripped +58 -72
Disabling record cache for self-joined multi update statement is wrong.
The join must only see the table as it was at the beginning of the statement.
safe_update_on_fly check if it is safe to update first table on the fly, that is
not creating temporary table. It is possible in case a row from this table is
never read more than once. safe_update_on_fly now detect self-joined table and
refuse to update this table on the fly.
# This is a BitKeeper patch. What follows are the unified diffs for the
# set of deltas contained in the patch. The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User: svoj
# Host: april.(none)
# Root: /home/svoj/devel/mysql/BUG21310/mysql-4.1-engines
--- 1.67/sql/lock.cc 2006-12-01 20:13:21 +04:00
+++ 1.68/sql/lock.cc 2006-12-01 20:13:21 +04:00
@@ -478,6 +478,7 @@ MYSQL_LOCK *mysql_lock_merge(MYSQL_LOCK
thd The current thread.
table The table to check for duplicate lock.
tables The list of tables to search for the dup lock.
+ for_update Exclude 'table' from check.
NOTE
This is mainly meant for MERGE tables in INSERT ... SELECT
@@ -494,7 +495,8 @@ MYSQL_LOCK *mysql_lock_merge(MYSQL_LOCK
0 No duplicate lock found.
*/
-int mysql_lock_have_duplicate(THD *thd, TABLE *table, TABLE_LIST *tables)
+int mysql_lock_have_duplicate(THD *thd, TABLE *table, TABLE_LIST *tables,
+ bool for_update)
{
MYSQL_LOCK *mylock;
TABLE **lock_tables;
@@ -529,6 +531,8 @@ int mysql_lock_have_duplicate(THD *thd,
{
table2= tables->table;
if (table2->tmp_table == TMP_TABLE)
+ continue;
+ if (for_update && table == table2)
continue;
/* All tables in list must be in lock. */
--- 1.382/sql/mysql_priv.h 2006-12-01 20:13:21 +04:00
+++ 1.383/sql/mysql_priv.h 2006-12-01 20:13:21 +04:00
@@ -1046,7 +1046,8 @@ void mysql_lock_remove(THD *thd, MYSQL_L
void mysql_lock_abort(THD *thd, TABLE *table);
bool mysql_lock_abort_for_thread(THD *thd, TABLE *table);
MYSQL_LOCK *mysql_lock_merge(MYSQL_LOCK *a,MYSQL_LOCK *b);
-int mysql_lock_have_duplicate(THD *thd, TABLE *table, TABLE_LIST *tables);
+int mysql_lock_have_duplicate(THD *thd, TABLE *table, TABLE_LIST *tables,
+ bool for_update);
bool lock_global_read_lock(THD *thd);
void unlock_global_read_lock(THD *thd);
bool wait_if_global_read_lock(THD *thd, bool abort_on_refresh, bool is_not_commit);
--- 1.488/sql/sql_parse.cc 2006-12-01 20:13:21 +04:00
+++ 1.489/sql/sql_parse.cc 2006-12-01 20:13:21 +04:00
@@ -2941,7 +2941,7 @@ unsent_create_error:
insert_table= tables->table;
/* MERGE sub-tables can only be detected after open. */
- if (mysql_lock_have_duplicate(thd, insert_table, tables->next))
+ if (mysql_lock_have_duplicate(thd, insert_table, tables->next, false))
{
/* Using same table for INSERT and SELECT */
select_lex->options |= OPTION_BUFFER_RESULT;
--- 1.157/sql/sql_update.cc 2006-12-01 20:13:21 +04:00
+++ 1.158/sql/sql_update.cc 2006-12-01 20:13:21 +04:00
@@ -23,8 +23,6 @@
#include "mysql_priv.h"
#include "sql_select.h"
-static bool safe_update_on_fly(JOIN_TAB *join_tab, List<Item> *fields);
-
/* Return 0 if row hasn't changed */
static bool compare_record(TABLE *table, ulong query_id)
@@ -846,27 +844,68 @@ int multi_update::prepare(List<Item> &no
for (i=0 ; i < table_count ; i++)
set_if_bigger(max_fields, fields_for_table[i]->elements);
copy_field= new Copy_field[max_fields];
+ DBUG_RETURN(thd->is_fatal_error != 0);
+}
- /*
- Mark all copies of tables that are updates to ensure that
- init_read_record() will not try to enable a cache on them
- The problem is that for queries like
+/*
+ Check if table is safe to update on fly
- UPDATE t1, t1 AS t2 SET t1.b=t2.c WHERE t1.a=t2.a;
+ SYNOPSIS
+ safe_update_on_fly
+ join_tab How table is used in join
+ all_tables List of tables
+ fields Fields that are updated
- the row buffer may contain things that doesn't match what is on disk
- which will cause an error when reading a row.
- (This issue is mostly relevent for MyISAM tables)
- */
- for (table_ref= all_tables; table_ref; table_ref=table_ref->next)
- {
- TABLE *table=table_ref->table;
- if ((tables_to_update & table->map) &&
- mysql_lock_have_duplicate(thd, table, update_tables))
- table->no_cache= 1; // Disable row cache
+ NOTES
+ We can update the first table in join on the fly if we know that
+ a row in this tabel will never be read twice. This is true under
+ the folloing conditions:
+
+ - We are doing a table scan and the data is in a separate file (MyISAM) or
+ if we don't update a clustered key.
+
+ - We are doing a range scan and we don't update the scan key or
+ the primary key for a clustered table handler.
+
+ - Table is not joined to itself.
+
+ WARNING
+ This code is a bit dependent of how make_join_readinfo() works.
+
+ RETURN
+ 0 Not safe to update
+ 1 Safe to update
+*/
+
+static bool safe_update_on_fly(THD *thd, JOIN_TAB *join_tab,
+ TABLE_LIST *all_tables, List<Item> *fields)
+{
+ TABLE *table= join_tab->table;
+ /* First check if a table is not joined to itself. */
+ if (mysql_lock_have_duplicate(thd, table, all_tables, true))
+ return 0;
+ switch (join_tab->type) {
+ case JT_SYSTEM:
+ case JT_CONST:
+ case JT_EQ_REF:
+ return 1; // At most one matching row
+ case JT_REF:
+ return !check_if_key_used(table, join_tab->ref.key, *fields);
+ case JT_ALL:
+ /* If range search on index */
+ if (join_tab->quick)
+ return !check_if_key_used(table, join_tab->quick->index,
+ *fields);
+ /* If scanning in clustered key */
+ if ((table->file->table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
+ table->primary_key < MAX_KEY)
+ return !check_if_key_used(table, table->primary_key, *fields);
+ return 1;
+ default:
+ break; // Avoid compler warning
}
- DBUG_RETURN(thd->is_fatal_error != 0);
+ return 0;
}
@@ -905,7 +944,7 @@ multi_update::initialize_tables(JOIN *jo
table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);
if (table == main_table) // First table in join
{
- if (safe_update_on_fly(join->join_tab, &temp_fields))
+ if (safe_update_on_fly(thd, join->join_tab, all_tables, &temp_fields))
{
table_to_update= main_table; // Update table on the fly
continue;
@@ -949,59 +988,6 @@ multi_update::initialize_tables(JOIN *jo
tmp_tables[cnt]->file->extra(HA_EXTRA_WRITE_CACHE);
}
DBUG_RETURN(0);
-}
-
-/*
- Check if table is safe to update on fly
-
- SYNOPSIS
- safe_update_on_fly
- join_tab How table is used in join
- fields Fields that are updated
-
- NOTES
- We can update the first table in join on the fly if we know that
- a row in this tabel will never be read twice. This is true under
- the folloing conditions:
-
- - We are doing a table scan and the data is in a separate file (MyISAM) or
- if we don't update a clustered key.
-
- - We are doing a range scan and we don't update the scan key or
- the primary key for a clustered table handler.
-
- WARNING
- This code is a bit dependent of how make_join_readinfo() works.
-
- RETURN
- 0 Not safe to update
- 1 Safe to update
-*/
-
-static bool safe_update_on_fly(JOIN_TAB *join_tab, List<Item> *fields)
-{
- TABLE *table= join_tab->table;
- switch (join_tab->type) {
- case JT_SYSTEM:
- case JT_CONST:
- case JT_EQ_REF:
- return 1; // At most one matching row
- case JT_REF:
- return !check_if_key_used(table, join_tab->ref.key, *fields);
- case JT_ALL:
- /* If range search on index */
- if (join_tab->quick)
- return !check_if_key_used(table, join_tab->quick->index,
- *fields);
- /* If scanning in clustered key */
- if ((table->file->table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
- table->primary_key < MAX_KEY)
- return !check_if_key_used(table, table->primary_key, *fields);
- return 1;
- default:
- break; // Avoid compler warning
- }
- return 0;
}
--- 1.68/mysql-test/r/myisam.result 2006-12-01 20:13:21 +04:00
+++ 1.69/mysql-test/r/myisam.result 2006-12-01 20:13:21 +04:00
@@ -944,3 +944,19 @@ select * from t1;
a
42
drop table t1;
+CREATE TABLE t1(a VARCHAR(16));
+INSERT INTO t1 VALUES('aaaaaaaa'),(NULL);
+UPDATE t1 AS ta1, t1 AS ta2 SET ta1.a='aaaaaaaaaaaaaaaa';
+SELECT * FROM t1;
+a
+aaaaaaaaaaaaaaaa
+aaaaaaaaaaaaaaaa
+DROP TABLE t1;
+CREATE TABLE t1(a INT);
+INSERT INTO t1 VALUES(1),(2);
+UPDATE t1,t1 AS t2 SET t1.a=t1.a+2 WHERE t1.a=t2.a-1;
+SELECT * FROM t1 ORDER BY a;
+a
+2
+3
+DROP TABLE t1;
--- 1.54/mysql-test/t/myisam.test 2006-12-01 20:13:21 +04:00
+++ 1.55/mysql-test/t/myisam.test 2006-12-01 20:13:21 +04:00
@@ -890,4 +890,23 @@ connection default;
select * from t1;
drop table t1;
+#
+# BUG#21310 - Trees in SQL causing a "crashed" table with MyISAM storage
+# engine
+#
+
+# A simplified test case that reflect crashed table issue.
+CREATE TABLE t1(a VARCHAR(16));
+INSERT INTO t1 VALUES('aaaaaaaa'),(NULL);
+UPDATE t1 AS ta1, t1 AS ta2 SET ta1.a='aaaaaaaaaaaaaaaa';
+SELECT * FROM t1;
+DROP TABLE t1;
+
+# A test case that reflect wrong result set.
+CREATE TABLE t1(a INT);
+INSERT INTO t1 VALUES(1),(2);
+UPDATE t1,t1 AS t2 SET t1.a=t1.a+2 WHERE t1.a=t2.a-1;
+SELECT * FROM t1 ORDER BY a;
+DROP TABLE t1;
+
# End of 4.1 tests
| Thread |
|---|
| • bk commit into 4.1 tree (svoj:1.2534) BUG#21310 | Sergey Vojtovich | 1 Dec |
