Multi-threaded mysqld lockup issue with ~50-53 second timeout (simultaneous states "updating/"Waiting for table metadata lock"/"Waiting for table flush")
Affects | Status | Importance | Assigned to | Milestone | ||
---|---|---|---|---|---|---|
MySQL Server |
Unknown
|
Unknown
|
||||
Percona Server moved to https://jira.percona.com/projects/PS | Status tracked in 5.7 | |||||
5.1 |
Won't Fix
|
Undecided
|
Unassigned | |||
5.5 |
New
|
High
|
Unassigned | |||
5.6 |
Triaged
|
High
|
Unassigned | |||
5.7 |
Triaged
|
High
|
Unassigned |
Bug Description
Testcase:
1. Branch lp:percona-qa and cd pquery
2. Startup mysqld (I used Percona-
3. Execute:
export LD_LIBRARY_
./pquery --infile=./out.2 --database=test --threads=100 --verbose --user=root --socket=
4. Connect with mysql cli client and repeat SHOW PROCESSLIST;
5. Wait a while till lockup starts appearing. It will look like this (I've removed a few redundant columns to make paste clearer):
mysql> show processlist;
+------
| Id | Command | Time | State | Info |
+------
| 1238 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1239 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1240 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1241 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1242 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1243 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1244 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1245 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1246 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1247 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1248 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1249 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1250 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1251 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1252 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1253 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1254 | Query | 47 | updating | DELETE FROM t2 LIMIT 1 |
| 1255 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1256 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1257 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1258 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1259 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1260 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1261 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1262 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1263 | Query | 46 | Waiting for table flush | FLUSH TABLES |
| 1264 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1265 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1266 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1267 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1268 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1269 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1270 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1271 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1272 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1273 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1274 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1275 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1276 | Query | 46 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1277 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1278 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1279 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1280 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1281 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1282 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1283 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1284 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1285 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1286 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1287 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1288 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1289 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1290 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1291 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1292 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1293 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1294 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1295 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1296 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1297 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1298 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1299 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1300 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1301 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1302 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1303 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1304 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1305 | Query | 47 | Waiting for table flush | INSERT INTO t2 VALUES (1,2,3) |
| 1306 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1307 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1308 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1309 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1310 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1311 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1312 | Query | 47 | updating | DELETE FROM t2 LIMIT 1 |
| 1313 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1314 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1315 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1316 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1317 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1318 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1319 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1320 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1321 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1322 | Query | 47 | updating | DELETE FROM t2 LIMIT 1 |
| 1323 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1324 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1325 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1326 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1327 | Query | 47 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1328 | Query | 47 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1329 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1330 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1331 | Query | 47 | updating | DELETE FROM t2 LIMIT 1 |
| 1332 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1333 | Query | 47 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1334 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1335 | Query | 47 | Waiting for table flush | FLUSH TABLES |
| 1336 | Query | 47 | Waiting for table metadata lock | DROP TABLE t2 |
| 1337 | Query | 47 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1338 | Query | 0 | init | show processlist |
+------
101 rows in set (0.00 sec)
And, after some sort of (hardcoded?) 50-53 second timeout is hit (the threads with 0-1 second time are fresh commands - they are not relevant):
mysql> show processlist;
+------
| Id | Command | Time | State | Info |
+------
| 1238 | Query | 1 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1239 | Query | 0 | Waiting for table metadata lock | DELETE FROM t1 LIMIT 1 |
| 1240 | Query | 0 | Waiting for table metadata lock | INSERT INTO t1 VALUES (1,2,3) |
| 1241 | Query | 1 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1242 | Query | 1 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1243 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1244 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1245 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1246 | Query | 1 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1247 | Query | 0 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1248 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1249 | Query | 1 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) |
| 1250 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1251 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1252 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1253 | Query | 0 | Waiting for table metadata lock | DROP TABLE t1 |
| 1254 | Query | 1 | creating table | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) |
| 1255 | Query | 1 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1256 | Query | 1 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1257 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1258 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1259 | Query | 0 | Waiting for table metadata lock | SELECT c1 FROM t1 |
| 1260 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1261 | Query | 0 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1262 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1263 | Query | 0 | Waiting for table metadata lock | SELECT c1 FROM t1 |
| 1264 | Query | 0 | Waiting for table metadata lock | SELECT c1 FROM t1 |
| 1265 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1266 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1267 | Query | 1 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1268 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1269 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1270 | Query | 0 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) |
| 1271 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1272 | Query | 0 | init | COMMIT |
| 1273 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1274 | Query | 1 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1275 | Query | 1 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) |
| 1276 | Query | 51 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1277 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1278 | Query | 1 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1279 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1280 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1281 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1282 | Query | 0 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) |
| 1283 | Query | 1 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1284 | Query | 0 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1285 | Query | 1 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1286 | Query | 0 | Waiting for table metadata lock | INSERT INTO t1 VALUES (1,2,3) |
| 1287 | Query | 0 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1288 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1289 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1290 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1291 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1292 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1293 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1294 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1295 | Query | 1 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) |
| 1296 | Query | 1 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1297 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1298 | Query | 0 | closing tables | DROP TABLE t2 |
| 1299 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1300 | Query | 0 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) |
| 1301 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1302 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1303 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1304 | Query | 0 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1305 | Query | 0 | Waiting for table metadata lock | SELECT c1 FROM t1 |
| 1306 | Query | 0 | Waiting for table metadata lock | SELECT c1 FROM t1 |
| 1307 | Query | 1 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1308 | Query | 1 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1309 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1310 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1311 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1312 | Query | 0 | Waiting for table metadata lock | DROP TABLE t1 |
| 1313 | Query | 0 | Waiting for table metadata lock | DELETE FROM t1 LIMIT 1 |
| 1314 | Query | 0 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1315 | Query | 1 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1316 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1317 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1318 | Query | 1 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1319 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1320 | Query | 1 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1321 | Query | 0 | Waiting for table metadata lock | SELECT c1 FROM t1 |
| 1322 | Query | 1 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1323 | Query | 0 | Waiting for table metadata lock | DROP TABLE t1 |
| 1324 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1325 | Query | 1 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1326 | Query | 0 | Waiting for table metadata lock | DROP TABLE t2 |
| 1327 | Query | 52 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1328 | Query | 52 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1329 | Query | 0 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1330 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1331 | Query | 1 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1332 | Query | 0 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1333 | Query | 52 | Waiting for table metadata lock | CREATE TABLE t2 (c1 INT,c2 INT,c3 INT) |
| 1334 | Query | 0 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1335 | Query | 0 | Waiting for table metadata lock | INSERT INTO t2 VALUES (1,2,3) |
| 1336 | Query | 1 | Waiting for table metadata lock | SELECT c1 FROM t2 |
| 1337 | Query | 52 | Waiting for table metadata lock | DELETE FROM t2 LIMIT 1 |
| 1338 | Query | 0 | init | show processlist |
+------
101 rows in set (0.00 sec)
The issue is consistently repeatable, and it's always around 50-53 (likely 53) seconds that the state "resets".
Confirmed with Percona- Server- 5.6.20- rel68.0- 657.Linux. x86_64- debug.
Some statements reset on 53 seconds but some continues ..
mysql> show processlist; ------+ ------- ----+-- ----+-- ------- +------ +------ ------- ------- ------- ------+ ------- ------- ------- ------- ------- -----+- ------- ---+--- ------- -----+ ------+ ------- ----+-- ----+-- ------- +------ +------ ------- ------- ------- ------+ ------- ------- ------- ------- ------- -----+- ------- ---+--- ------- -----+
+-----+
| Id | User | Host | db | Command | Time | State | Info | Rows_sent | Rows_examined |
+-----+
| 5 | root | localhost | test | Query | 102 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) | 0 | 0 |
| 6 | root | localhost | test | Query | 51 | Waiting for table metadata lock | DROP TABLE t1 | 0 | 0 |
| 7 | root | localhost | test | Query | 102 | Waiting for table metadata lock | DROP TABLE t1 | 0 | 0 |
| 8 | root | localhost | test | Query | 102 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) | 0 | 0 |
| 9 | root | localhost | test | Query | 102 | Waiting for table flush | DELETE FROM t1 LIMIT 1 | 0 | 0 |
| 10 | root | localhost | test | Query | 102 | Waiting for table flush | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) | 0 | 0 |
| 11 | root | localhost | test | Query | 51 | Waiting for table flush | FLUSH TABLES | 0 | 0 |
| 12 | root | localhost | test | Query | 102 | Waiting for table metadata lock | DROP TABLE t1 | 0 | 0 |
| 13 | root | localhost | test | Query | 51 | Waiting for table metadata lock | INSERT INTO t1 VALUES (1,2,3) | 0 | 0 |
| 14 | root | localhost | test | Query | 102 | Waiting for table metadata lock | CREATE TABLE t1 (c1 INT,c2 INT,c3 INT) | 0 | 0 |
| 15 | root | localhost | test | Query | 102 | Waiting for table flush | INSERT INTO t1 VALUES (1,2,3) | 0 | 0 |
| 16 | root | localhost | test | Query | 102 | Waiting for table metadata lock | SELECT c1 FROM t1 | 0 | 0 |
| 17 | root | localhost | test | Query | 51 | Waiting for table flush | FLUSH TABLES | 0 | 0 |
| 18 | root | localhost | test | Query | 102 | Waiting for table metadata lock | INSERT INTO t1 VALUES (1,2,3) | 0 | 0 |
| 19 | root | localhost | test | Query | 102 | Waiting for table metadata lock | INSERT INTO t1 VALUES (1,2,3) | 0 | 0 |
| 20 | root | localhost | test | Query | 102 | Waiting for table metadata lock | INSERT INTO t1 VALUES (1,2,3) | 0 | 0 |
| 21 | root | localhost | test | Query | 51 | Waiting for table metadata lock | DELETE FROM t1 LIMIT 1 ...