As you probably know PHP “mysql” extension supported persistent connections but they were disabled in new “… reduce recycle delay. Reducing last one however will go against protocol requirements so in theory you can get some problems. It worked… could get much more problems with it. Persistent connections were added to PHP during times of MySQL 3.22/3.23 when MySQL was…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
…here that the ALTER waits only at the last stages when its making changes to the table …I have reported a bug: http://bugs.mysql.com/bug.php?id=67647 Metadata locking behaves differently …get piled up waiting for table metadata lock bringing down the MySQL server or causing all the connections to get…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…, or last refeshed. The incremental method is somewhat conceptually similar to using mysql binary … to the Flexviews API (see convert.php below) Refresh methods The incremental refresh … contents of the view. mysql> select flexviews.get_sql( -> flexviews.get_id(‘demo’,'dashboard_customer_sales’)) -> …
Post: Debugging sleeping connections with MySQL
February 8, 2007 By 30 Comments
… originated from php stream functions not from libmysql or memcache.so, which means it is not MySQL or memcache connections leaving last candidate… see the URL which that process is processing and so get few more hints on what may be happening or even… process are not only helpful to debug sleeping connections with MySQL but many other cases when you see web application locking…
Post: PHP Large result sets and summary tables.
July 6, 2007 By 8 Comments
…… but not for larger ones. First problem was PHP script generating the table took 10GB of RAM …the only real call you can get errors is when you run mysql_query , mysql_fetch_row simply reads data … column ranges instead. I would especially recommend this last way for very long processes, ie if you …
Post: Caching could be the last thing you want to do
July 24, 2010 By 14 Comments
… you should be caring more that all users get a good experience (Peter explains why here, talking…-digest to capture queries. Run them through MySQL‘s EXPLAIN command. Do your queries SELECT *, only…- a quote from Justin’s slides on instrumentation-for-php. In terms of future-proofing design, many…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
… discussed in the comments of the last post. ICE does not have any…from 1988 to 2010′; mysql> use ontime1; Database changed mysql> show table status like ‘…(adjust to your number of nodes) php genconfig 20 > shards.ini Running …#we value throughput over response time, get a good plan optimizer-prune-…
Post: Should MySQL and Web Server share the same box ?
October 16, 2006 By 9 Comments
…decide ether to grow system in MySQL+Apache pairs or split MySQL And Web Server and place them…etc. I would however only use it in last resort – placing some data crunching scripts on …get Web boxes with relatively plenty of memory cheap but unless you’re running 500 Apache children with mod_P (php…
Post: thread_concurrency doesn't do what you expect
June 4, 2012 By 3 Comments
… last months I’ve seen lots of customers trying to tune the thread concurrency inside MySQL with the variable…and removed on 5.6.1 http://bugs.mysql.com/bug.php?id=55001 2- It only works on …there are hundred of MySQL tuning howtos that explain how to tune the variable to get better performance. If …
Post: Content delivery system design mistakes
February 11, 2007 By 9 Comments
… helped dealing with performance problems (part MySQL related and part related to LAMP in general)… noatime mount option Serving images you rarely need last access time tracked for them, especially as …as lighttpd tries to buffer all content it gets from PHP script which means many megabytes for large…
