… after the upgrade was completed regardless of its state before updating. This caused some problems for some users, especially if automatic… statements on an existing table could wait on a metadata lock instead of failing or returning immediately if there is a… documentation. Bugs can be reported on the launchpad bug tracker. UPDATE[18-04-2013]: There was a RPM packaging regression introduced…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
… a player makes an achievement, your application updates this table with a statement like this: UPDATE achievements SET count = count + 1 where… might you do that ? Write to one node If your issue is really the deadlock errors and not so much the… the lock waiting that your application will need to do for hotspots. wsrep_retry_autocommit If your hotspots are all updates with…
Comment: Implications of Metadata Locking Changes in MySQL 5.5
March 27, 2013 By 9 Comments
… doing is that by executing an update query on the table, the transaction holds row locks on row with the id=3… innodb_lock_wait_timeout to 1 and then issuing the ALTER: — session 1 start transaction; select * from t1 where id=3 for update; — session 2 set innodb_lock_wait…
Post: Innodb Table Locks
July 31, 2012 By 4 Comments
… id 12304 lock_mode X When updating the table it also gets “locked“, now with IX lock… this is because update needs to lock the rows… table level locks because innodb will only set intentional level locks for everything by DDL operations. If you’re having locking issues with Innodb chances are it is row level locks or auto increment table level lock (mostly with MySQL…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
… flags: STMT_END_F BINLOG ‘ L5cLURMBAAAALwAAAAUDAAAAABEAAAAAAAEABHRlc3QABHRlc3QAAwMD/gL+CQY= L5cLURgBAAAAOAAAAD0DAAAAABEAAAAAAAEAA///+AIAAAAAAAAAA2JhcvgCAAAAAAAAAANob3A= ‘/*!*/; ### UPDATE test.test ### WHERE ### @1=2 /* INT meta=0 nullable=0… UPDATE, because ALTER did not block waiting for the transaction to commit. For the reasons described above the implementation of Metadata Locking… cannot really apply any other event. This was never an issue when the application was using MySQL version < 5.5 as…
Comment: INSERT ON DUPLICATE KEY UPDATE and REPLACE INTO
October 26, 2011 By 15 Comments
… for that. I was wondering if INSERT … UPDATE might lock for read access (or lock only the index, or something simmilar) while checking… lock for write access when performing the update. This would lead to a deadlock when trying to upgrade two read locks to write locks… I described is really happenning? Might a REPLACE solve the issue? Would it work right where INSERT … UPDATE locks?
Post: Investigating MySQL Replication Latency in Percona XtraDB Cluster
March 3, 2013 By 13 Comments
…: sysbench –test=oltp –oltp-test-mode=nontrx –oltp-nontrx-mode=update_key –mysql-user=root –mysql-password=”" –oltp-table-size=1000000… delays but it visibly stalls, as I guess because the UPDATE statement issued to DPE1 is blocked for some time. To check… binlog_format=ROW default_storage_engine=InnoDB innodb_autoinc_lock_mode=2 innodb_locks_unsafe_for_binlog=1 wsrep_sst_auth=root:
Post: Index lock and adaptive search - next two biggest InnoDB problems
February 25, 2010 By 12 Comments
…. So I suspect it’s going to be next biggest issues to make InnoDB scaling on high-end system. This is… read / write queries, InnoDB locks index for write operation and thus keeps all selects waiting when update/insert is done. This is… be done there internally: there is B-Tree lock free or only page-level lock algorithms, so operation does not need to…
Comment: Benchmarks of new innodb_flush_neighbor_pages
July 3, 2012 By 8 Comments
… I dont know if it will help for Selects and Updates http://mysqlopt.blogspot.com/2012/06/mysql-how-to-scale… on log file sizes and stalls/lockups, even though the lock issue might be solved for this I still think the idea… should be better ways of allowing read and writes without locking ie. a special algorithm. I think something like the Deadline…
Post: Using MyISAM in production
June 17, 2006 By 36 Comments
… rows may end up being updated, and you might not know which ones. Concurrency. MyISAM uses table locks and has concurrent inserts… is enough. Lock priorities. By default MySQL treats updates as higher priority operations. You can use SELECT HIGH_PRIORITY or UPDATE LOW_PRIORITY…). You can use multiple of cache tables to avoid concurrency issues. Temporary tables used in batch processing and other means Exported…
