Re: Protect syscache from bloating with negative cache entries

On Tue, Feb 19, 2019 at 07:08:14AM +0000, Tsunakawa, Takayuki wrote:
> We all have to manage things within resource constraints.  The DBA
> wants to make sure the server doesn't overuse memory to avoid crash
> or slowdown due to swapping.  Oracle does it, and another open source
> database, MySQL, does it too.  PostgreSQL does it with shared_buffers,
> wal_buffers, and work_mem (within a single session).  Then, I thought
> it's natural to do it with catcache/relcache/plancache.

I already addressed these questions in an email from Feb 14:

    https://www.postgresql.org/message-id/20190214154955.GB19578@momjian.us

I understand the operational needs of limiting resources in some cases,
but there is also the history of OS's using working set to allocate
things, which didn't work too well:

    https://en.wikipedia.org/wiki/Working_set

I think we need to address the most pressing problem of unlimited cache size
bloat and then take a holistic look at all memory allocation.  If we
are going to address that in a global way, I don't see the relation
cache as the place to start.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
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