… -> /var/lib/mysql/ibdata1 (deleted) lrwx—— 1 root root 64 Aug 7 23:29 8 -> /var/lib/mysql/ib_logfile0 (deleted) lrwx—— 1 root root 64 Aug 7 23:29 9 -> /var/lib/mysql/ib_logfile1 (deleted) where 14101… 16644 Purge done for trx’s n:o < 0 16644 undo n:o < 0 0 But if the last transaction wasn…
Post: How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
…fill up the disk. #!/bin/bash # Begin by deleting things more than 7 days old find /root/…and port ${port} > /root/tcpdumps/`date +%s`-tcpdump & mysql -e ‘show innodb status\Gshow full processlist’ > /root/tcpdumps/`…that was blocking others and had locks and undo log records, yet had only run SELECT …
Post: Innodb undo segment size and transaction isolation
January 12, 2011 By 3 Comments
…, ACTIVE 15867 sec, process no 19349, OS thread id 1630148928 MySQL thread id 188790, query id 14796224615 host.domain.com 127… on undo space usage. Inserts only have a small record in undo space so row can be deleted on rollback, update and delete however need to put the old row version in undo space…
Post: InnoDB's gap locks
March 27, 2012 By 15 Comments
… a SELECT. They only occur if you do UPDATE or DELETE or SELECT FOR UPDATE. InnoDB provides REPEATABLE READ for read… | | 25 | | 30 | +——+ Start a transaction and delete the record 25: transaction1 > START TRANSACTION; transaction1 > DELETE FROM t WHERE age=25; At this…(s), heap size 1248, 3 row lock(s), undo log entries 1 MySQL thread id 3, OS thread handle 0x7f84a78ba700, query id…
Post: ACTIVE with Locks – Now thats a problem !
June 2, 2011 By 2 Comments
… ACTIVE transactions which have some locks, like in this case: MySQL thread id 2059, query id 1014425 10.10.10.10…(s), heap size 368, 1 row lock(s), undo log entries 1 MySQL thread id 1720, query id 1011283 10.10.10…), undo log entries 2 In this case we see transactions are holding some locks and perform some update/deletes as there are undo…
Post: INSERT INTO ... SELECT Performance with Innodb tables.
July 12, 2006 By 22 Comments
… be done fore replication to work right in MySQL before 5.1. In MySQL 5.1 this as well as few other… aproach make sure to delete file after it is loaded back (it has to be done outside of MySQL Server) as otherwise… or deleting mysql tables in use 1, locked 1 LOCK WAIT 3 lock struct(s), heap size 320, undo log entries 1 MySQL thread…
Post: MySQL 5.6: Improvements in the Nutshell
January 27, 2013 By 16 Comments
…January I have created the outline of improvements available in MySQL 5.6 which I thought was worth sharing to give…UPDATE/DELETE queries – - JSON output with more information – Optimizer Tracing – Deadlock Logging – GET DIAGNOSTICS Operational Improvements – Separate Tablespaces for Innodb Undo Logs…
Post: Percona Server 5.1.59-13.0
October 16, 2011 By Leave a Comment
…high overhead from locking rows only to undo changes at rollback. Using this approach, support… reading the rows for “INSERT“, “UPDATE“ and “DELETE“ statements but not updating them (Fake Changes),…KEY. #851674 (Alexey Kopytov). Backported fix for MySQL bug #53761 (Wrong estimate for RANGE query…
Post: Percona Server 5.5.16-22.0
October 16, 2011 By 2 Comments
…and from the Percona Software Repositories). Based on MySQL 5.5.16, including all the bug … high overhead from locking rows only to undo changes at rollback. Using this approach, support … By reading the rows for “INSERT“, “UPDATE“ and “DELETE“ statements but not updating them (Fake Changes), …
Post: Recovery after DROP & CREATE
August 22, 2012 By 1 Comment
… rows affected (0.56 sec) # ./page_parser -f /var/lib/mysql/ibdata1 # ./bin/constraints_parser.SYS_TABLES -4Df pages-1345220873/FIL… UNDO segment SYS_TABLES and SYS_INDEXES are normal InnoDB tables. They’re also ruled by MVCC. When a record is deleted from SYS_TABLES it is copied to the undo segment. A pointer to the old…
