[TYPO3-english] Database cleaning advice

[mario chiari]

Hi

very useful, ypu may think to save it as a wiki entry somewhere.
thanks cheers
mario

On Sat, 2016-05-28 at 23:05 +0200, Jigal van Hemert wrote:
> Hi,
> 
> On 28/05/2016 18:33, Chad Manookin wrote:
> > 
> > The database of our Typo3 installation (version 4.5.45 -- trust me, I'm
> > working to get upgraded) has become huge, making backups a pain and
> > possibly slowing the site.
> > 
> > While I've been working with it for just under a year, from what I
> > understand the site has been running for ~8 years, which leads me to
> > believe that a lot of unnecessary 'tracking' data has accumulated. The
> > problem is, I don't know what I can clear safely, or how exactly I
> > should go about it.
> > 
> > The biggest table, by far, is tx_realurl_chashcache that clocks in at
> > 822 MiB. Since it would drop the total size of the database by nearly
> > 1/3, does anyone know if there is a safe way to clear out old data in
> > this table?
> > 
> > Same question regarding sys_log and cache_hash since they are ~500 MiB
> > each.
> cache_* tables are the "old" cache tables. They can all be emptied, 
> except for cache_extensions. This one contains the list of available TER 
> extensions. It can be emptied, but the you'd have to download the list 
> again and you end up with exactly the same table size.
> 
> cf_* tables are cache tables from the (newer) caching framework; they 
> can be emptied
> 
> sys_history contains the changes editors made. This helps you to roll 
> back any changes that must be undone. You can empty it, but you'll lose 
> the ability to undo modifications in content.
> 
> sys_log contains all logged information. Who logged in, pages that were 
> added/removed/modified, record changes, extension changes, etcetera. If 
> you don't mind losing that (the information you see in the Log module) 
> it can be emptied too.
> 
> tx_realurl_chashcache contains calculated hashes for links. It's a 
> cache, it can be emptied.
> tx_realurl_errorlog contains requests that didn't have a correct 
> realurl. Can be emptied if you don't want to preserve the information
> tx_realurl_pathcache can be emptied if necessary
> tx_realurl_redirects : keep it!
> tx_realurl_uniquealias : better keep it. It keeps track of record IDs 
> and titles. If there are multiple records from the same table with the 
> same title the title with numeric suffix is stored here. For this reason 
> the information should be kept.
> tx_realurl_urldecodecache, tx_realurl_urlencodecache can be emptied
> 
> 
>