We have seen this user creating issues to itself mostly, with long running inserts which are locking themselves.
root@labsdb1005.eqiad.wmnet[(none)]> show full processlist;
| 124602858 | s51434 | 10.68.18.9:34751 | s51434__mixnmatch_p | Query | 18588 | Waiting for table metadata lock | TRUNCATE common_names_human | 0.000 |
| 124613830 | s51434 | 10.68.23.154:47035 | s51434__mixnmatch_p | Query | 1466 | Sending data | SELECT /*!40001 SQL_NO_CACHE */ * FROM `entry` | 0.000 |
| 124613884 | s51434 | 10.68.17.89:53344 | s51434__mixnmatch_p | Query | 19516 | Waiting for table level lock | INSERT IGNORE INTO overview (catalog) VALUES (1734) | 0.000 |
| 124614704 | s51434 | 10.68.18.14:39975 | s51434__mixnmatch_p | Query | 16737 | Waiting for table level lock | UPDATE entry SET q=56503087,user=4,`timestamp`='20180907045734' WHERE id=30067009 AND (user is null or user=0 or q=-1) | 0.000 |
| 124616592 | s51434 | 10.68.17.89:54630 | s51434__mixnmatch_p | Query | 19189 | Waiting for table level lock | INSERT IGNORE user (name,last_block_check) VALUES ('redacted','1536293802') | 0.000 |
| 124616660 | s51434 | 10.68.17.89:54634 | s51434__mixnmatch_p | Query | 19183 | Waiting for table level lock | INSERT IGNORE user (name,last_block_check) VALUES ('redacted','1536293808') | 0.000 |
| 124616745 | s51434 | 10.68.17.89:54640 | s51434__mixnmatch_p | Query | 19174 | Waiting for table level lock | INSERT IGNORE user (name,last_block_check) VALUES ('redacted','1536293817') | 0.000 |
| 124619317 | s51434 | 10.68.19.159:56107 | s51434__mixnmatch_p | Query | 18868 | Waiting for table level lock | UPDATE autoscrape SET status='RUNNING' WHERE id=986 | 0.000 |
| 124620447 | s51434 | 10.68.23.172:51658 | s51434__mixnmatch_p | Query | 18731 | Waiting for table level lock | UPDATE entry SET q=15945237,user=4,`timestamp`='20180907042420' WHERE id=24062596 AND (user is null or user=0 or q=-1) | 0.000 |
| 124643471 | s51434 | 10.68.21.65:52337 | s51434__mixnmatch_p | Query | 16852 | Waiting for table level lock | UPDATE entry SET q=56452973,user=4,`timestamp`='20180907045539' WHERE id=57025604 AND (user is null or user=0 or q=-1) | 0.000 |
| 124658872 | s51434 | 10.68.21.42:60753 | s51434__mixnmatch_p | Query | 15267 | Waiting for table level lock | UPDATE autoscrape SET status='RUNNING' WHERE id=986 | 0.000 |
| 124684305 | s51434 | 10.68.23.154:59405 | s51434__mixnmatch_p | Query | 13344 | Waiting for table level lock | UPDATE entry SET q=56214481,user=4,`timestamp`='20180907055407' WHERE id=18288222 AND (user is null or user=0 or q=-1) | 0.000 |
| 124701810 | s51434 | 10.68.22.236:35021 | s51434__mixnmatch_p | Query | 11667 | Waiting for table level lock | UPDATE autoscrape SET status='RUNNING' WHERE id=986 | 0.000 |
| 124725885 | s51434 | 10.68.22.236:35383 | s51434__mixnmatch_p | Query | 9913 | Waiting for table level lock | UPDATE entry SET q=21406824 WHERE id=32973067 AND q=33681648 | 0.000 |
| 124727354 | s51434 | 10.68.21.65:52569 | s51434__mixnmatch_p | Query | 9671 | Waiting for table metadata lock | TRUNCATE common_names_taxon | 0.000 |
| 124745072 | s51434 | 10.68.23.172:48834 | s51434__mixnmatch_p | Query | 8068 | Waiting for table level lock | UPDATE autoscrape SET status='RUNNING' WHERE id=986 | 0.000 |
| 124790057 | s51434 | 10.68.19.24:57973 | s51434__mixnmatch_p | Query | 4467 | Waiting for table level lock | UPDATE autoscrape SET status='RUNNING' WHERE id=986 | 0.000 |
| 124790064 | s51434 | 10.68.23.223:55194 | s51434__mixnmatch_p | Query | 4467 | Waiting for table level lock | update catalog set type='biography' where type='unknown' AND active=1 AND (SELECT count(*) from entry WHERE catalog=catalog.id)=(SELECT count(*) from entry WHERE catalog=catalog.id AND type='person') | 0.000 |
| 124821891 | s51434 | 10.68.18.137:45024 | s51434__mixnmatch_p | Query | 2509 | Waiting for table level lock | UPDATE entry SET q=29272560,user=4,`timestamp`='20180907085442' WHERE id=41487507 AND (user is null or user=0 or q=-1) | 0.000 |
| 124843304 | s51434 | 10.68.17.239:50277 | s51434__mixnmatch_p | Query | 867 | Waiting for table level lock | UPDATE autoscrape SET status='RUNNING' WHERE id=986 | 0.000 |
| 124855022 | s51434 | 10.68.17.202:36287 | s51434__mixnmatch_p | Query | 143 | Waiting for table level lock | UPDATE entry SET q=8841371,user=4,`timestamp`='20180907093408' WHERE id=53201367 AND (user is null or user=0 or q=-1) | 0.000 |
95 rows in set (0.00 sec)This is mostly only creating issues to itself, however this could impact somehow other users as it is using more and more resources from the host.
If this keeps growing I will set a connection limit for this user to make sure it doesn't keep increasing