Re: Allowing line-continuation in pgbench custom scripts

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
Cc: Amit Langote <amitlangote09(at)gmail(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Allowing line-continuation in pgbench custom scripts
Date: 2014-05-26 21:19:05
Message-ID: 5383AFC9.1060901@agliodbs.com
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On 05/26/2014 08:52 AM, Tom Lane wrote:
> Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> writes:
>> Amit Langote wrote:
>>> On Mon, May 26, 2014 at 10:59 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>>>> IMO it's better if we can write SQL in multiples line *without* a tailing
>>>> escape character, like psql's input file.
>
>>> Yeah, that would be much cleaner.
>
>> But that would require duplicating the lexing stuff to determine where
>> quotes are and where commands end. There are already some cases where
>> pgbench itself is the bottleneck; adding a lexing step would be more
>> expensive, no? Whereas simply detecting line continuations would be
>> cheaper.
>
> Well, we only parse the script file(s) once at run start, and that time
> isn't included in the TPS timing, so I don't think performance is really
> an issue here. But yeah, the amount of code that would have to be
> duplicated out of psql is pretty daunting --- it'd be a maintenance
> nightmare, for what seems like not a lot of gain. There would also
> be a compatibility issue if we went this way, because existing scripts
> that haven't bothered with semicolon line terminators would break.

What if we make using semicolons or not a config option in the file? i.e.:

\multiline

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com

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