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Re: Partition prune and lock


the horizontal partition (2), could help us with
alter online table xxxx add field type;

2013/5/29 Roberto Spadim <roberto@xxxxxxxxxxxxx>

> Hi guys i'm studing mariadb code and reading user manuals to know more
> about features. My last study was about query cache with many ideas in some
> MDEV and some patchs sent
> Now i'm reading about partition
> My questions are
> 1)when a update or a delete is done on a expecific partition like:
> Update table set field=2 where partition=1
> How lock is done? Lock is done at table level or partition level?
> 2)Today we have vertical partition, could we implement 'virtual'
> horizontal partition
> update and delete in some group of fields (horizontal partition) only lock
> the horizontal partition being changed and used in where clausule?
> Any idea and problems on how to develop it?
> 3) can query cache be partition pruned?
> instead of removing entire table, just remove the partition that was
> changed
> It will consume more memory but will do a better work in cache
> Maybe a new key like SQL_CACHE_PARTITON or a new variable,
> query_cache_min_unit=PARTITION or TABLE could change how the query will be
> cached and pruned
> Thanks guys

Roberto Spadim