Comments on: Caching techinques http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/ Everything about MySQL Performance Tue, 02 Dec 2008 14:29:59 +0000 http://wordpress.org/?v=2.5.1 By: peter http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-4923 peter Wed, 11 Oct 2006 07:17:23 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-4923 Marcus, This is in average some 5 connections/sec and 25 queries/sec, not much at all. In your case load is very light in terms of query numbers so this method should not cause large overhead. Marcus,

This is in average some 5 connections/sec and 25 queries/sec, not much at all. In your case load is very light in terms of query numbers so this method should not cause large overhead.

]]> By: Markus http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-4918 Markus Wed, 11 Oct 2006 00:19:13 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-4918 We're using this locking method for a web application. To draw some numbers, at this moment, the server has been running for about 21 hours. There have been 414,322 connections that have executed 6,654,212 questions, being 1,952,321 of them selects. That's about 16 questions (around 5 selects) per connection average, but not all of them are cached. Maybe our experience may serve someone else out there. Cheers We’re using this locking method for a web application. To draw some numbers, at this moment, the server has been running for about 21 hours. There have been 414,322 connections that have executed 6,654,212 questions, being 1,952,321 of them selects. That’s about 16 questions (around 5 selects) per connection average, but not all of them are cached. Maybe our experience may serve someone else out there. Cheers

]]> By: peter http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-4821 peter Sat, 07 Oct 2006 21:37:20 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-4821 Markus, If you have single cache request per page you probably do not care, in this sense all listed techniques would work just fine. If you have many cache lookups it is however other story. Ie 100 cache lookups would cause 100ms of just _overhead_ not to count cache access itself. So I do not think this approach is the most optimal but it will be good enough in many cases. If it delivers good enough performance in your case - use it :) Markus,

If you have single cache request per page you probably do not care, in this sense all listed techniques would work just fine. If you have many cache lookups it is however other story. Ie 100 cache lookups would cause 100ms of just _overhead_ not to count cache access itself.

So I do not think this approach is the most optimal but it will be good enough in many cases.

If it delivers good enough performance in your case - use it :)

]]> By: Markus http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-4817 Markus Sat, 07 Oct 2006 12:38:32 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-4817 Peter, thanks for your feedback. I made some tests and noticed just 1 millisecond or less overhead when using GET_LOCK/RELEASE_LOCK to queue accesses to cached files. The one thing that liked me of this approach is implementation was as easy as adding the requests to get and release the locks in the proper places and, in case of problems, they will be released as soon as each connection ends. I would like to point out to this thread where I've been posting my thoughts in more depth: http://area51.phpbb.com/phpBB/viewtopic.php?f=4&t=25059 Cheers Peter, thanks for your feedback.

I made some tests and noticed just 1 millisecond or less overhead when using GET_LOCK/RELEASE_LOCK to queue accesses to cached files. The one thing that liked me of this approach is implementation was as easy as adding the requests to get and release the locks in the proper places and, in case of problems, they will be released as soon as each connection ends.

I would like to point out to this thread where I’ve been posting my thoughts in more depth:
http://area51.phpbb.com/phpBB/viewtopic.php?f=4&t=25059

Cheers

]]> By: peter http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-2634 peter Mon, 18 Sep 2006 19:45:09 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-2634 Markus. If you're working with files you probbably should do locking by file locks (assuming they work in your envinronment) Or you can use shared memory semaphores if you're running inside single host. Using GET_LOCK() will work but it is expensive - it is query to MySQL server which needs parsing etc. Markus. If you’re working with files you probbably should do locking by file locks (assuming they work in your envinronment) Or you can use shared memory semaphores if you’re running inside single host. Using GET_LOCK() will work but it is expensive - it is query to MySQL server which needs parsing etc.

]]> By: Markus http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-2623 Markus Mon, 18 Sep 2006 07:24:24 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-2623 I have implemented a similar caching method than the one described in Jay's blog. Our site is growing so I tried to do some things before getting to buy more hardware. I just noticed (in Jay's cache class) that reads to cached files aren't locked, so more than one concurrent process could try to execute the query and rebuild the cached file at the same time. I was was thinking to lock cache reads using MySQL function GET_LOCK. I'm wondering if such a thing really worths. Any advice? Thanks a lot, this blog has been helping me a lot! I have implemented a similar caching method than the one described in Jay’s blog. Our site is growing so I tried to do some things before getting to buy more hardware. I just noticed (in Jay’s cache class) that reads to cached files aren’t locked, so more than one concurrent process could try to execute the query and rebuild the cached file at the same time.

I was was thinking to lock cache reads using MySQL function GET_LOCK. I’m wondering if such a thing really worths. Any advice?

Thanks a lot, this blog has been helping me a lot!

]]> By: Seems appropriate… » Dude, WTF?! http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-1771 Seems appropriate… » Dude, WTF?! Mon, 14 Aug 2006 19:30:10 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-1771 [...] MySQL Performance Blog [...] [...] MySQL Performance Blog [...]

]]> By: peter http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-1579 peter Tue, 08 Aug 2006 21:15:26 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-1579 Apachez, It is trackback from existing page which seems to be more or less valid this is why I leave it :) Apachez,

It is trackback from existing page which seems to be more or less valid this is why I leave it :)

]]> By: Apachez http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-1578 Apachez Tue, 08 Aug 2006 21:09:10 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-1578 Uhm, whats the point of above comment? Looks like spam to me... Uhm, whats the point of above comment?

Looks like spam to me…

]]> By: Sameer Maggon’s Web Log » Blog Archive » MySQL / PHP - Connection Management http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-1577 Sameer Maggon’s Web Log » Blog Archive » MySQL / PHP - Connection Management Tue, 08 Aug 2006 19:36:03 +0000 http://www.mysqlperformanceblog.com/2006/08/08/caching-techinques/#comment-1577 [...] The above article discusses two issues viz. Connection Management and Caching. It’s also worth looking at an article written by Peter Zaitsev who provides more details on Caching Techniques. [...] [...] The above article discusses two issues viz. Connection Management and Caching. It’s also worth looking at an article written by Peter Zaitsev who provides more details on Caching Techniques. [...]

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