Re: [HACKERS] Protect syscache from bloating with negative cache entries - Mailing list pgsql-hackers

From David Steele
Subject Re: [HACKERS] Protect syscache from bloating with negative cache entries
Date
Msg-id 6eb3b24b-c0eb-b8ca-f847-609704e2a370@pgmasters.net
Whole thread Raw
In response to Re: [HACKERS] Protect syscache from bloating with negative cacheentries  (Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>)
Responses Re: [HACKERS] Protect syscache from bloating with negative cache entries  (David Steele <david@pgmasters.net>)
List pgsql-hackers
On 2/1/17 1:25 AM, Kyotaro HORIGUCHI wrote:
> Hello, thank you for moving this to the next CF.
> 
> At Wed, 1 Feb 2017 13:09:51 +0900, Michael Paquier <michael.paquier@gmail.com> wrote in
<CAB7nPqRFhUv+GX=eH1bo7xYHS79-gRj1ecu2QoQtHvX9RS=JYA@mail.gmail.com>
>> On Tue, Jan 24, 2017 at 4:58 PM, Kyotaro HORIGUCHI
>> <horiguchi.kyotaro@lab.ntt.co.jp> wrote:
>>> Six new syscaches in 665d1fa was conflicted and 3-way merge
>>> worked correctly. The new syscaches don't seem to be targets of
>>> this patch.
>>
>> To be honest, I am not completely sure what to think about this patch.
>> Moved to next CF as there is a new version, and no new reviews to make
>> the discussion perhaps move on.
> 
> I'm thinking the following is the status of this topic.
> 
> - The patch stll is not getting conflicted.
> 
> - This is not a hollistic measure for memory leak but surely
>   saves some existing cases.
> 
> - Shared catcache is another discussion (and won't really
>   proposed in a short time due to the issue on locking.)
> 
> - As I mentioned, a patch that caps the number of negative
>   entries is avaiable (in first-created - first-delete manner)
>   but it is having a loose end of how to determine the
>   limitation.

While preventing bloat in the syscache is a worthwhile goal, it appears
there are a number of loose ends here and a new patch has not been provided.

It's a pretty major change so I recommend moving this patch to the
2017-07 CF.

-- 
-David
david@pgmasters.net



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