Details
-
Bug
-
Status: Closed (View Workflow)
-
Major
-
Resolution: Fixed
-
10.4(EOL), 10.5, 10.6, 10.7(EOL), 10.8(EOL), 10.9(EOL), 10.10(EOL), 10.11, 11.1(EOL)
Description
This is a serious locking bug where Spider fails to see that table t was already created previously (and not locked?).
Affects optimized and debug builds. Issue is not sporadic.
INSTALL PLUGIN Spider SONAME 'ha_spider.so'; |
CREATE USER Spider@localhost IDENTIFIED BY 'PWD123'; |
CREATE SERVER srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET '../socket.sock',DATABASE 'test',user 'Spider',PASSWORD 'PWD123'); |
CREATE TABLE t (c INT) ENGINE=InnoDB; |
CREATE TABLE t1 (c INT) ENGINE=Spider; |
CREATE TABLE t2 (c INT) ENGINE=Spider COMMENT='WRAPPER "mysql",srv "srv",TABLE "t"'; |
LOCK TABLES t2 WRITE;
|
LOCK TABLES t1 READ; |
CREATE TABLE t (c INT) ENGINE=Spider; |
Leads to:
|
10.11.0 bc563f1a4b0b38de3b41fd0f0d3d8b7f1aacbd8b (Optimized) |
10.11.0-dbg>LOCK TABLES t1 READ;
|
ERROR 1429 (HY000): Unable to connect to foreign data source: localhost
|
10.11.0-dbg>CREATE TABLE t(c INT) ENGINE=Spider;
|
# Hang
|
|
10.11.0 bc563f1a4b0b38de3b41fd0f0d3d8b7f1aacbd8b (Optimized) |
10.11.0-opt>SHOW FULL PROCESSLIST;
|
+----+-------------+-----------+------+---------+------+----------------------------------------------------+-------------------------------------+----------+
|
| Id | User | Host | db | Command | Time | State | Info | Progress |
|
+----+-------------+-----------+------+---------+------+----------------------------------------------------+-------------------------------------+----------+
|
| 5 | root | localhost | test | Query | 77 | Waiting for table metadata lock | CREATE TABLE t(c INT) ENGINE=Spider | 0.000 |
|
| 6 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 7 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 8 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 9 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 10 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 11 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 12 | system user | | NULL | Sleep | 77 | Reset for next command | NULL | 0.000 |
|
| 13 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 14 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 17 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 18 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 20 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 19 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 24 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 15 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 22 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 16 | system user | | NULL | Daemon | NULL | Spider table background cardinality action handler | NULL | 0.000 |
|
| 21 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 23 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 25 | system user | | NULL | Daemon | NULL | Spider table background statistics action handler | NULL | 0.000 |
|
| 26 | spider | localhost | test | Sleep | 77 | | NULL | 0.000 |
|
| 27 | root | localhost | test | Query | 0 | starting | SHOW FULL PROCESSLIST | 0.000 |
|
+----+-------------+-----------+------+---------+------+----------------------------------------------------+-------------------------------------+----------+
|
23 rows in set (0.001 sec)
|
Attachments
Issue Links
- is blocked by
-
-
- Closed
-
- is part of
-
-
- Closed
-
- relates to
-
-
- Closed
-
Activity
So if I understand you correctly, for items 1+3, you are saying that LOCK TABLES t2 WRITE; - executed by the root at the CLI - will trigger the Spider engine to automatically lock table t - in a background (and non-user) thread, which uses the Spider UserID, and is done by the server/the Spider SE - because t is being referenced/linked in the t2 table definition?
Mostly yes, but there is no background thread. The thread handling the user CLI connection also handles the Spider (background) connection.
I believe that the following test case found in the investigation for MDEV-29484 reproduces the present bug.
--disable_query_log
|
--disable_result_log
|
--source ../../t/test_init.inc
|
--enable_result_log
|
--enable_query_log
|
|
--connection child2_1
|
CREATE DATABASE auto_test_remote; |
USE auto_test_remote; |
eval CREATE TABLE tbl_a ( |
a INT |
) $CHILD2_1_ENGINE $CHILD2_1_CHARSET;
|
|
--connection master_1
|
CREATE DATABASE auto_test_local; |
USE auto_test_local; |
eval CREATE TABLE tbl_a ( |
a INT |
) $MASTER_1_ENGINE $MASTER_1_CHARSET COMMENT='table "tbl_a", srv "s_2_1"'; |
eval CREATE TABLE tbl_b ( |
a INT |
) $MASTER_1_ENGINE $MASTER_1_CHARSET;
|
|
LOCK TABLES tbl_a WRITE;
|
--error 1429
|
LOCK TABLES tbl_b READ, tbl_a READ; |
|
--connection master_1
|
DROP DATABASE IF EXISTS auto_test_local; |
|
--connection child2_1
|
DROP DATABASE IF EXISTS auto_test_remote; |
|
--disable_query_log
|
--disable_result_log
|
--source ../t/test_deinit.inc
|
--enable_query_log
|
--enable_result_log |
I can reprod the hang at 11.1 (4e5b771e980edfdad5c5414aa62c81d409d585a4) when running the test case in the previous comment.
Please note that SET GLOBAL spider_same_server_link=ON; is not used here.