…. So I put 114GB as size of data after load, until someone points … of records, however calculates it pretty fast. Q0: select avg(c1) from (select year… TABLES, which is big limitation from my point of view. As workaround …further tests, as it took good amount of time to deal with different glitches…
Post: Quickly finding unused indexes (and estimating their size)
December 5, 2012 By 2 Comments
… enforce important application data constraints, so we added some additional criteria to the end of our SELECT. I can now select my droppable (unused… doing first? Do these indexes actually represent a significant enough amount of disk space for it to be worth our while? We… easily see how big each index is if we dropped it (not big in this case with test data): mysql> select * from droppable_indexes…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
…HT: You are right, bugs that cause data corruption, crashes, or wrong query results… boxes with larger amounts of RAM, to give INNODB ~70-80% of the total RAM, … up in “show innodb statusâ€. select * from table where id=5 show …your database like? Do you have a big enough buffer pool? PZ: I guess…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…at “real-time.” None of the big three (Google, Yahoo,…of data you’ll need in those aggregate tables, and include columns to support these queries. But beware of denormalizing with character data… can save very large amounts of space. Choose primary … the master with INSERT..SELECT queries, it will …
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… heavily loaded or has a lot of data, touching the INFORMATION_SCHEMA can …that can be fixed and bring big gains. Schema, query, and index …no other technique that approaches the amount of information a Percona build can give…I run EXPLAIN if possible (rewriting non-SELECT queries if needed, and using …
Post: Choosing innodb_buffer_pool_size
November 3, 2007 By 39 Comments
… larger than your data (total size of Innodb TableSpaces) because it does not only contain data pages – it … small sized boxes to 5% of memory size on the big boxes, though it can be …described Innodb Buffer Pool selection for dedicated Innodb system. If you have fair amount of MyISAM, Archive, PBXT, …
Post: Side load may massively impact your MySQL Performance
November 13, 2011 By 7 Comments
…db=test –oltp-table-name=md_cache_test_big –oltp-table-size=17600000 –mysql-user=msandbox –… > select concat_ws(‘.’, t.schema, t.name, i.name) as index_name, sum(data_size)/1024/1024 as data… a variable innodb_old_blocks_time which specifies amount of milliseconds which needs to pass before table …
Post: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
…/mnt/data/sandboxes/msb_5_5_30/data/ | /mnt/data/sandboxes/msb_5_6_10/data/…of 1MB now allowing MySQL to handle larger queries. Makes sense as amount of…big change and is good one. We have been running innodb_file_per_table=1 for most of…localhost] {msandbox} (test) > select * from var55 where variable…
Post: Fighting MySQL Replication Lag
September 22, 2008 By 7 Comments
…amount of values per batch in multiple row insert statement or Fetching data…SELECT going through replication in 5.0 for many reasons (locking, long query time, waste of execution on slave). Piping data…
Post: MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
…of full table scan. Not all queries are going to be affected same way, for example point select…amount of tables and does specified number of…of opening and closing MyISAM table) can happen by OS in background and flushing 1000 pages each 30 seconds is not big… growth of many tables causes data …
