…that really helps encapsulate a lot of this information and puts it into context with your application … things the rule does not mean on Galera It does NOT mean you can’t modify different rows … change your schema In Example 2, above, how above moving the ‘joined’ column to the users_groups table so…
Post: MySQL opening .frm even when table is in table definition cache
November 21, 2011 By 8 Comments
… the range of numbers for dynamic assignment and what this means for on-disk compatibility of data directories is left as… paths in the server: DROP TABLE RENAME TABLE DROP VIEW open table filling INFORMATION_SCHEMA tables (I think it is actually the TABLES table, but didn’t look… disk IO for information it already has cached (often at least twice – in InnoDB itself and in the table_definition_cache). Further…
Post: SHOW OPEN TABLES - what is in your table cache
December 14, 2008 By 3 Comments
… (even if table is opened more than ones) In_use show how many threads are currently using this table, meaning have it locked or waiting on the table lock for this table to lock it. Name_locked… lock right now. It also deserves to be converted to INFORMATION_SCHEMA table – so it would be easily to operate it using SQL…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
… to a value of 0(zero), which means that pages move rapidly from the cold …information_schema.innodb_buffer_page_lru where table_name like ‘%ssb%’ group by 1,2 ) sq order by pct_buffer_pool desc; +——————-+——————+——-+——+——+———+—————–+ | table…
Comment: Learning about MySQL Table Fragmentation
May 18, 2012 By 20 Comments
…(data_free / ( 1024 * 1024 ), 2), ‘MB’)FREE from information_schema.TABLES where TABLE_SCHEMA=’xyz’ and table_name=’abc’ and Data_free > 0 limit 10; and… information_schema.TABLES where TABLE_SCHEMA=’xyz’ and table_name=’abc’ and Data_free > 0 limit 10; still the free space remains the same. that means that table…
Post: How much space does empty Innodb table take ?
December 16, 2008 By 7 Comments
…) which means this value is going to be changing back and forth and it would be very inaccurate for small tables. For…. Using innodb_file_per_table can cause significant space use overhead if small tables are used The information in INFORMATION_SCHEMA can’t be used to judge how much space table is really taking…
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 64 Comments
… few cache implementations which I’d call an Active Cache meaning it takes care of the misses itself, without you have… different comments is especially important as many application put extra information in the comments to assist diagnosing the application, such as… Query Cache content and operation can be presented as some INFORMATION_SCHEMA tables. Self Refresh MySQL Query Cache causes not uniform performance as…
Post: Query Response time histogram - new feature in Percona Server
July 11, 2010 By 11 Comments
… engineer Oleg Tsarev implemented this feature. The feature adds new INFORMATION_SCHEMA table QUERY_RESPONSE_TIME ( full docs are on page response_time… 2889362 0.100000 19341 1.000000 7040 and which basically means that there were 7040 queries with execution time less than…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… heavily loaded, I may even do some INFORMATION_SCHEMA queries to help me find the biggest tables and so forth. If the server… that there are InnoDB tables whose .frm files exist but have been dropped from InnoDB, for example. (The INFORMATION_SCHEMA query will surely… the amount of information a Percona build can give you. Having found the desired information about the queries by any means necessary, I…
Post: Find unused indexes
June 30, 2012 By Leave a Comment
… the information on INDEX_STATISTICS table. mysql> SELECT * FROM INDEX_STATISTICS; +————–+————+————–+———–+ | TABLE_SCHEMA | TABLE_NAME | INDEX_NAME | ROWS_…means all the other indexes has been used during the benchmark. The second limitation is with partitioned tables…
