… use this particular form of query because it will do full table scan – running count(*) without where clause may pick to… indication of bad fragmentation was average IO size seen in SHOW INNODB STATUS output. It was around 20KB which means most reads are… scan performance even if table is not logically fragmented and Innodb is reading data in large blocks – this can happen in…
Post: MySQL Error Message Nonsenses
March 16, 2008 By 7 Comments
… (66666); ERROR 1114 (HY000): The table ‘yt’ is full For me table is full means something like I’m out of disk… free slot for an undo log. Do you have too InnoDB: many active transactions running concurrently? I hope with pluggable storage… key related but you also need to run SHOW INNODB STATUS to see what exactly Innodb did not like about foreign key constraint definition…
Post: MySQL Prepared Statements
August 2, 2006 By 21 Comments
… query with different parameters did not require passing full query to the server and full parsing. (Note: Optimization phase currently remains). Not…. Logs were now fixed to include full statement text not only “Execute” but in SHOW INNODB STATUS you would still see statements without actual…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
…_tables: 0 Tmp_table_sizes: 0 # InnoDB_trx_id: F00 # QC_Hit: No Full_scan: Yes Full_join: No Tmp_table: No Tmp…+ # Tables # SHOW TABLE STATUS FROM `wp_blog_one ` LIKE ‘wp_terms’\G # SHOW CREATE TABLE `wp_blog_one `.`wp_terms`\G # SHOW TABLE STATUS FROM `wp_blog_one ` LIKE ‘wp_term_taxonomy’\G # SHOW CREATE TABLE `wp_blog_one `.`wp_term_taxonomy`\G # SHOW TABLE STATUS…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…shows…status where variable_name like ‘%innodb%read%’; +—————————————+—————-+ | VARIABLE_NAME | VARIABLE_VALUE | +—————————————+—————-+ | INNODB_BUFFER_POOL_READ_AHEAD_RND | 0 | | INNODB_BUFFER_POOL_READ_AHEAD | 38392 | | INNODB…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…InnoDB contain primary key columns) Buffer each pk_column value fetched from step 1, and when the buffer is full…for Innodb_buffer_pool_read_ahead which shows that the access pattern was sequential and hence InnoDB… seen by the numbers reported for the status counter Innodb_rows_read. While MySQL 5.6…
Post: Troubleshooting MySQL Upgrade Performance Regressions
February 15, 2012 By Leave a Comment
… on servers. Best if you can analyze full query logs but if this is not …. You may consider disabling innodb_stats_on_metadata and increasing innodb-stats-sample-pages to get …low level. FLUSH STATUS; SHOW STATUS can show whenever internal operation is different, you can also check SHOW PROFILE to …
Post: The new cool MySQL patch has landed! Check your queries performance!
October 31, 2007 By 16 Comments
… the execution in the log file. # QC_Hit: No Full_scan: No Full_join: No Tmp_table: Yes Disk_tmp_table: No… are the InnoDB usage statistics. MySQL currently allows you to see many per-session statistics for operations with SHOW SESSION STATUS, but that does not include those of InnoDB, which are always global and shared…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
… for my application. I have profiled it with SHOW STATUS and I know it causes a great many …the key_buffer_size until, when the buffer is full, Key_reads/Uptime reduces to a number you’…about InnoDB tuning? You might be wondering, what about InnoDB tuning? What is the best way to choose an innodb_…
Post: Announcing Percona XtraBackup 1.6.7
December 21, 2012 By 1 Comment
… innobackupex confused the response from SHOW SLAVE STATUS with the one from SHOW MASTER STATUS. Bug fixed #977101 (Alexey Kopytov). innodb_data_file_path was… a wrong directory when merging an incremental backup to a full one. Bug fixed #1002688 (Alexey Kopytov). XtraBackup binary was leaking…
