Re: bad estimation together with large work_mem generates terrible slow hash joins

From: Tomas Vondra <tv(at)fuzzy(dot)cz>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: bad estimation together with large work_mem generates terrible slow hash joins
Date: 2014-09-10 19:12:37
Message-ID: 5410A2A5.9010100@fuzzy.cz
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On 10.9.2014 20:25, Heikki Linnakangas wrote:
> On 09/10/2014 01:49 AM, Tomas Vondra wrote:
>> I also did a few 'minor' changes to the dense allocation patch, most
>> notably:
>>
>> * renamed HashChunk/HashChunkData to MemoryChunk/MemoryChunkData
>> The original naming seemed a bit awkward.
>
> That's too easy to confuse with regular MemoryContext and AllocChunk
> stuff. I renamed it to HashMemoryChunk.

BTW this breaks the second patch, which is allocating new chunks when
resizing the hash table. Should I rebase the patch, or can the commiter
do s/MemoryChunk/HashMemoryChunk/ ?

Assuming there are no more fixes needed, of course.

Tomas

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