Re: [HACKERS] pgbench: faster version of tpcb-like transaction - Mailing list pgsql-hackers

From Fabien COELHO
Subject Re: [HACKERS] pgbench: faster version of tpcb-like transaction
Date
Msg-id alpine.DEB.2.20.1708270721380.18068@lancre
Whole thread Raw
In response to Re: [HACKERS] pgbench: faster version of tpcb-like transaction  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hello Tom,

> I dunno, it seems like this proposal involves jacking up the test case
> and driving a completely different one underneath.  There is no reason
> to consider that you've improved the benchmark results --- you've just
> substituted a different benchmark, one with no historical basis, and
> not a lot of field justification either.

ISTM that putting some SQL in a function and calling it is standard 
practice in some classes of applications, although probably not the most 
frequent.

Moreover, as far as the TPC-B benchmark is concerned, it looks like a 
perflectly legitimate implementation of the benchmark: the transaction 
profile (Section 1.2) is described as 4 inputs sent in and one result 
returned. The fact that the SQL commands are sent one at a time by the 
client to the server is a pgbench choice that I would not have done if I 
wanted to show the greatest TPC-B numbers with Pg.

Nor does it mean that it is a bad idea to do so... For instance an ORM web 
application might tend to generate simple unprepared CRUD queries and 
interact a lot back and forth, and the default test is not to bad to 
reflect that particular kind of behavior.

Basically there are different kind of application implementations and 
different tests could reflect those. So I am fine with providing more 
benchmarking options to pgbench, and I intend to do so once its 
capabilities are improved.

A caveat I have with Jeff patch is that "tpcb-func" is a misnommer because 
pgbench does NOT implement tpcb per spec, and it is my intention to 
propose a variant which does implement the spec when possible. Now I think 
that I'm also responsible for the prefix constraint on names...

-- 
Fabien.



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