… which is a worst-case scenario for spinning disks. This is also very hard to prove, … are many subtleties including the possibility of having multiple key caches. But I’ll give the simple…the results to your IO system’s capabilities. MySQL doesn’t have good instrumentation for scientifically choosing…
Post: How InnoDB handles REDO logging
February 3, 2011 By 19 Comments
… in the log needs to be able to be redone multiple times since at restart and media recovery we will not… the log to disk at commit. By this means you are ensuring that in the event of a MySQL crash the data… REDO logging and the checkpoint on disk. Vadim touched upon this subject recently in his post MySQL 5.5.8 – in…
Post: Is disk Everything for MySQL Performance ?
April 25, 2008 By 7 Comments
… ask how many disks they have instead of how many systems they have” on MySQL UC2008 Scalability Panel ? Indeed disks MAY be the… space and how much data we can comfortably put in MySQL Instance without getting in too much trouble with backups etc… potential serialization issues along you need enough concurrency to utilize multiple hard drives and with 50 drives you would need at…
Post: Quickly finding unused indexes (and estimating their size)
December 5, 2012 By 2 Comments
…-out and you risk dropping necessary indexes. To accomplish merging multiple result sets, I gathered statistics from both their master and… how much disk space an index utilizes. Let’s go update our all_indexes view to include this information: mysql> drop view… droppable_indexes view to use that information: mysql> drop view if exists droppable_indexes; mysql> create view droppable_indexes as select all…
Post: Full Text Search Webinar Questions Followup
August 24, 2012 By 5 Comments
… sorting by default, adding relevance sorting to the MySQL queries would make them even slower, I’m … solution. David S. asked: Q: If searching on multiple terms, can you get Sphinx to report which … because you’re searching data without touching the disk, but I assume the search would necessarily do…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…. It is possible to distribute splitting and/or loading among multiple nodes as well. Note that in the demonstration each node… file size on disk: 42GB (with indexes) # du -sh * 203M ibdata1 128M ib_logfile0 128M ib_logfile1 988K mysql 2.1G ontime1…=’Contains all avaialble data from 1988 to 2010′; mysql> use ontime1; Database changed mysql> show table status like ‘ontime_fact’G *************************** 1…
Post: Finding what Created_tmp_disk_tables with log_slow_filter
September 22, 2008 By 3 Comments
…_disk_tables | 74 | | Created_tmp_files | 3 | | Created_tmp_tables | 357 | Luckily this client was running the Percona patched version of MySQL… plan. Multiple flags allowed in a comma-separated string. [qc_miss, full_scan, full_join, tmp_table, tmp_table_on_disk, filesort, filesort_on_disk] So now all I had to do was set…
Post: Side load may massively impact your MySQL Performance
November 13, 2011 By 7 Comments
… CPU needs and be bound by disk. Also these are just 2 “threads” …mysql –mysql-host=localhost –mysql-table-engine=innodb –mysql-db=test –oltp-table-name=md_cache_test_small –oltp-table-size=1100000 –mysql-user=msandbox –mysql…) you are likely going to have multiple accesses to the data on the …
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… should expect from the system. What I usually look for MySQL is performance in random reads and random writes. Sequential reads…’t really get advantage of them unless you can get multiple outstanding requests. Performance with 64 threads was 2334.63 Requests… flushed to the disk in background – in this case there is little difference if we use one thread or multiple threads. As…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…_blocks_time=1000 on MySQL 5.5.30 and testing multiple buffer pools on MySQL 5.5.30. Finally, MySQL 5.6.10 has… be sure it wasn’t a disk problem, I pointed the MySQL 5.6.10 at the MySQL 5.5.30 data directory…, see how many pages were read from disk versus how many page requests their were: mysql> select * from information_schema.global_status…
