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Bug#56716 InnoDB locks a record gap without locking the table

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row_search_for_mysql(): Acquire an intention lock on the table
before locking the first record gap.
This commit is contained in:
Marko Mäkelä 2010-10-04 13:05:21 +03:00
parent 6d46ba951f
commit 484e61a778
3 changed files with 50 additions and 36 deletions
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4
mysql-test/suite/innodb/r/innodb_bug56716.result Normal file
View file

@ -0,0 +1,4 @@
CREATE TABLE bug56716 (a INT PRIMARY KEY,b INT,c INT,INDEX(b)) ENGINE=InnoDB;
SELECT * FROM bug56716 WHERE b<=42 ORDER BY b DESC FOR UPDATE;
a b c
DROP TABLE bug56716;

10
mysql-test/suite/innodb/t/innodb_bug56716.test Normal file
View file

@ -0,0 +1,10 @@
#
# Bug #56716 InnoDB locks a record gap without locking the table
#
-- source include/have_innodb.inc
CREATE TABLE bug56716 (a INT PRIMARY KEY,b INT,c INT,INDEX(b)) ENGINE=InnoDB;
SELECT * FROM bug56716 WHERE b<=42 ORDER BY b DESC FOR UPDATE;
DROP TABLE bug56716;

72
storage/innobase/row/row0sel.c
View file

@ -3599,6 +3599,42 @@ shortcut_fails_too_big_rec:
clust_index = dict_table_get_first_index(index->table);
/* Do some start-of-statement preparations */
if (!prebuilt->sql_stat_start) {
/* No need to set an intention lock or assign a read view */
if (trx->read_view == NULL
&& prebuilt->select_lock_type == LOCK_NONE) {
fputs("InnoDB: Error: MySQL is trying to"
" perform a consistent read\n"
"InnoDB: but the read view is not assigned!\n",
stderr);
trx_print(stderr, trx, 600);
fputc('\n', stderr);
ut_error;
}
} else if (prebuilt->select_lock_type == LOCK_NONE) {
/* This is a consistent read */
/* Assign a read view for the query */
trx_assign_read_view(trx);
prebuilt->sql_stat_start = FALSE;
} else {
err = lock_table(0, index->table,
prebuilt->select_lock_type == LOCK_S
? LOCK_IS : LOCK_IX, thr);
if (err != DB_SUCCESS) {
goto lock_wait_or_error;
}
prebuilt->sql_stat_start = FALSE;
}
/* Open or restore index cursor position */
if (UNIV_LIKELY(direction != 0)) {
ibool need_to_process = sel_restore_position_for_mysql(
&same_user_rec, BTR_SEARCH_LEAF,
@ -3674,42 +3710,6 @@ shortcut_fails_too_big_rec:
}
}
if (!prebuilt->sql_stat_start) {
/* No need to set an intention lock or assign a read view */
if (trx->read_view == NULL
&& prebuilt->select_lock_type == LOCK_NONE) {
fputs("InnoDB: Error: MySQL is trying to"
" perform a consistent read\n"
"InnoDB: but the read view is not assigned!\n",
stderr);
trx_print(stderr, trx, 600);
fputc('\n', stderr);
ut_a(0);
}
} else if (prebuilt->select_lock_type == LOCK_NONE) {
/* This is a consistent read */
/* Assign a read view for the query */
trx_assign_read_view(trx);
prebuilt->sql_stat_start = FALSE;
} else {
ulint lock_mode;
if (prebuilt->select_lock_type == LOCK_S) {
lock_mode = LOCK_IS;
} else {
lock_mode = LOCK_IX;
}
err = lock_table(0, index->table, lock_mode, thr);
if (err != DB_SUCCESS) {
goto lock_wait_or_error;
}
prebuilt->sql_stat_start = FALSE;
}
rec_loop:
/*-------------------------------------------------------------*/
/* PHASE 4: Look for matching records in a loop */