Horton

Re: Use generation context to speed up tuplesorts

Tomas Vondra <tomas.vondra@enterprisedb.com>

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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
To: Andres Freund <andres@anarazel.de>, David Rowley <dgrowleyml@gmail.com>, Tomas Vondra <tv@fuzzy.cz>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2021-07-31T02:34:04Z
Lists: pgsql-hackers

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Hi,

I spent a bit of time hacking on the Generation context, adding the two 
improvements discussed in this thread:

1) internal handling of block sizes, similar to what AllocSet does (it 
pretty much just copies parts of it)

2) keeper block (we keep one empry block instead of freeing it)

3) I've also added allocChunkLimit, which makes it look a bit more like 
AllocSet (instead of using just blockSize/8, which does not work too 
well with dynamic blockSize)

I haven't done any extensive tests on it, but it does pass check-world 
with asserts etc. I haven't touched the comments, those need updating.


regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Use Generation memory contexts to store tuples in sorts

  2. Adjust tuplesort API to have bitwise option flags

  3. Improve the generation memory allocator