[TYPO3] Cache_hash is growing fast. Trying to find the explanation.

[Erik Svendsen]

Hello!

On one of my installations the cache_hash table are growing really fast. 
About 500 MB in 24 hours. 

At this moment this isn't a big problem, because I have this site (for a 
client) on a new server with enough space.

I also know about the possibilities of;
config.no_cache = 1

or;
config.cache_period = some value
config.cache_clearAtMidnight = 1

I also see the possibility to make a cronjob (script) who truncate the cache_x 
tables at a regular basis.

But I'm trying to find the underlying cause for this fast growing of cache_hash. 
For instance a extension.

I have compared it with another installation who has a mainly the same configuration, 
numbers of menus, use of conditions in TS, and type of elements. There are 
different plugins on different pages, but on the root page there are few 
differences. Main difference is the use of ric_rotation on the site where. 
The problem site has also two domains (different sites in same installation). 
The two domain are configured 99,5 % indetical. To check the impact of every 
loaded page I tested both sites with a webserver stress tool (not ab2, but 
a tool who are doing as a normal user, navigation on the site). I tested 
with about 1400 pages on both, and there wasn't any big difference. The problemsite 
made 44 new post (1,2 MB) and the other 25 (800 kB).

So it's looks like there isn't any extensions who gives the fast growing 
of cache_hash.

Another difference between the two sites are the number of hits from Googlebot 
and other crawlers. The problemsite has about 11 000 hits from Googlebot 
in 17 days for each of the two domain (1300 a day). Could be part of the 
reason, but I can't find any logic in having such a number of bot hits.


WBR,
Erik Svendsen
www.linnearad.no