… large fc_limit in this case might mean a long wait before flow control gets relaxed again. However, this was recently… on any node by simply by running “FLUSH TABLES WITH READ LOCK”, or perhaps by “LOCK TABLE“, in which case flow control will…, I can easily see flow control if I execute a FLUSH TABLES WITH READ LOCK on node3: [root@node3 ~]# myq_status wsrep…
Post: Virident vCache vs. FlashCache: Part 2
May 17, 2013 By 3 Comments
…-based flushing“, and “vCache with time-based flushing.” As the images demonstrate, the no-cache system is being crushed by IO wait. FlashCache… –num-threads=32 –test=tests/db/oltp.lua –oltp_tables_count=32 \ –oltp-table-size=10000000 –rand-init=on –report-interval=1…_file_per_table = true innodb_data_file_path = ibdata1:100M innodb_flush_method = O_DIRECT innodb_log_buffer_size = 128M innodb_flush_log…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…are maintained in separate tables and there also exists a users_groups table to define the relationship …typical answers. However, this means more latency waiting for a write to go through, …counter in memcache or redis and only flushing to the database periodically? if( $last_count % 100 == 0 …
Post: Percona Server 5.5.30-30.2 rerelease fixes non-restart issue
April 24, 2013 By Leave a Comment
… been deprecated. Feature has been removed because the upstream DROP TABLE implementation has been improved. (Laurynas Biveinis) Bugs Fixed: Due to… the upstream bug #63144. CREATE TABLE or CREATE TABLE IF NOT EXISTS statements on an existing table could wait on a metadata lock instead… the upstream MySQL 5.6 the fix for unnecessary log_flush_order_mutex acquisition. Bug fixed #1163262 (Alexey Kopytov). When mysqldump…
Post: Percona Server for MySQL 5.5.30-30.2 now available
April 10, 2013 By 10 Comments
… been deprecated. Feature has been removed because the upstream DROP TABLE implementation has been improved. (Laurynas Biveinis) Bugs Fixed: Due to… the upstream bug #63144. CREATE TABLE or CREATE TABLE IF NOT EXISTS statements on an existing table could wait on a metadata lock instead… the upstream MySQL 5.6 the fix for unnecessary log_flush_order_mutex acquisition. Bug fixed #1163262 (Alexey Kopytov). When mysqldump…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
… | 0 | 0 | 2359297 | | 10290 | root | localhost | NULL | Query | 317 | Waiting for table flush | flush tables with read lock | 0 | 0 | 1 | | 10291 | root | localhost | dumptest… | NULL | Query | 681 | Waiting for table flush | flush tables with read lock | 0 | 0 | 1 | | 10291 | root | localhost | dumptest | Query | 74 | Waiting for global read lock…
Post: How fast is FLUSH TABLES WITH READ LOCK?
April 24, 2010 By 30 Comments
… also that “Flushing tables” is a misnomer — connection 5 is not flushing tables yet. It’s waiting to get the lock. Flushing tables After the FLUSH TABLES WITH READ LOCK command finally acquires the lock, it must begin flushing…
Post: MySQL optimizer: ANALYZE TABLE and Waiting for table flush
February 27, 2013 By 3 Comments
… like FLUSH TABLES, ALTER, RENAME, OPTIMIZE or REPAIR can cause threads to wait on “Waiting for tables“, “Waiting for table” and “Waiting for table flush“. Conclusion Before running an ANALYZE table or any other command listed before, check the running queries. If the table…
Post: SHOW OPEN TABLES - what is in your table cache
December 14, 2008 By 3 Comments
… threads are currently using this table, meaning have it locked or waiting on the table lock for this table to lock it. Name_locked… activity on the given table. Just run “FLUSH TABLES mytable” and examine open tables later – if you see this table in table cache again chances are…) – instead of running FLUSH TABLES on ALL tables one by one you can run SHOW OPEN TABLES and flush only open tables, when run it again…
Post: Hacking to make ALTER TABLE online for certain changes
October 29, 2007 By 26 Comments
…, you’d usually ALTER TABLE `huge_table` CHANGE `id` `id` int(6) NOT NULL and then wait hours for table rebuild to complete. If… is create another table with desired table structure and switch .frm table definition files. For safety, I’d recommend to flush tables with read lock…) flush tables with read lock, (3) swap .frm files while keeping mysql suspended and (4) unlock the tables afterwards: — 1. mysql> CREATE TABLE `huge_table…
