[wp-hackers] Use of ENGINE=MEMORY w/ dbDelta() possible?

DD32 wordpress at dd32.id.au
Mon Mar 24 04:15:51 GMT 2008

On Mon, 24 Mar 2008 14:57:03 +1100, Mahmoud Al-Qudsi <computerguru at neosmart.net> wrote:

>> Also, Some caches can be VERY large, some only small, I think i
>> remember some people having upwards of 50MB's in file caches just for
>> the object cache.
> Individual files too? With a varbinary(4096), it has support for up to 4KiB in a single cache object. The problem (as I'm sure you know) is that MEMORY tables are fixed-row-size; so I can't use BLOB, LONGTEXT, etc.

Not individual files, that was as a whole folder of files.

But 4KiB isnt much data really, its definately not enough to store multiple reasonable sized blog entries.

Which is why it was splitting it into 4 chunks, and then over multiple rows if need be.

Also, doing a delete for any row thats expired should be really quick with a memory table, If need be, you could even only run it on (rand(0,5) == 5), but i'd just take the slight performance hit myself and delete old rows, if you use a datetime, or a int field, it should be rather fast.

As a final note on this.. Is it worth running a mysql memory cache like this if you've got access ot mysql itself.
There are a few settings which allows mysql to cache queries much more efficiently, so that repeditive queries from WP are stored in memory.. 
http://www.arnebrachhold.de/2007/02/16/four-plus-one-ways-to-speed-up-the-performance-of-wordpress-with-caching/ ("MySQL Query Cache")

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