…. Nearly every solution for randomly choosing rows involves some compromise, either of performance,…reinitializing the sequence after making certain insert/update/delete operations. If you have a …count the movies per production year for each kind_id. It was more efficient in this case to force MySQL…
Post: Is your MySQL buffer pool warm? Make it sweat!
April 16, 2013 By 6 Comments
…1 –mysql-username playback –mysql-password PaSSwOrd –mysql-schema schema_name –query-log-stdin –dispatcher-plugin thread-pool –thread-pool-threads-count 100 –…query traffic. This is an important step because update statements that match no rows or insert statements that have duplicate key …
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
… effect on standard MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL replication? It’s … hundred rows. When a player makes an achievement, your application updates this table with a statement like this: UPDATE achievements SET count = count + …
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
…was using 8 tables with 1M rows each (about 2.1GB) for …=99 –mysql-user=root –mysql-db=sbtest8t1M –mysql-table-engine=INNODB –mysql-socket=/tmp/mysql.sock –…updates=0 –oltp-non-index-updates=0 run POINT_SELECT + UPDATE QPS test sysbench –num-threads=<1..1024> –test=oltp.lua –oltp_tables_count…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
…, which should produce updates in-place (I will use INSERT .. ON DUPLICATE KEY UPDATE statements for …can easily fill TokuDB tables with 1bln of rows on this SSD, and projected InnoDB performance… –oltp-table-size=10000 –mysql-user=root –oltp-tables-count=32 –mysql_table_engine=tokudb –oltp_auto_…
Post: Performance Schema tables stats
May 2, 2011 By 2 Comments
…rows in set (0.03 sec) Interesting that UPDATE/DELETE operations are not counted in INDEX_NAME: PRIMARY,the documentation says: “Inserts are counted…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL manual, especially the…row_lock_time_maxblogpercona.commanual Innodb_row_lock_waitsblogpercona.commanual Innodb_rows_deletedblogpercona.commanual Innodb_rows_insertedblogpercona.commanual Innodb_rows_readblogpercona.commanual Innodb_rows…unique_checksblogpercona.commanual updatable_views_with_…
Post: Debugging problems with row based replication
May 6, 2010 By 12 Comments
…with: select count(*) from t1; +———-+ | count(*) | +———-+ | 65536 | +———-+ 1 row in set (0.02 sec) My test setup includes a MySQL slave. …mysql_sandbox25162-relay-bin.000002 Relay_Log_Pos: 340718 Slave_SQL_Running: No Last_Errno: 1032 Last_Error: Could not execute Update_rows…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…row count (the first number is wall time, the second exec time, the third parse time). $ echo “select count…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
…want to look at Prepared_stmt_count to see how many prepared statements…ROWS: 0 AVG_ROW_LENGTH: 0 DATA_LENGTH: 16384 INDEX_LENGTH: 0 CREATE_TIME: NULL UPDATE_TIME: NULL *************************** 2. row… where your MySQL Support contract can be handy. Conclusion Understanding where MySQL can allocate…
