Horton

Re: reducing the footprint of ScanKeyword (was Re: Large writable variables)

David Fetter <david@fetter.org>

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From: David Fetter <david@fetter.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Andrew Gierth <andrew@tao11.riddles.org.uk>, John Naylor <jcnaylor@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2018-12-26T16:38:41Z
Lists: pgsql-hackers 
On Wed, Dec 26, 2018 at 11:22:39AM -0500, Tom Lane wrote:
> 
> In my hands, the only part of the low-level parsing code that
> commonly shows up as interesting in profiles is the Bison engine.

Should we be considering others? As I understand it, steps have been
made in this field since yacc was originally designed. Is LALR
actually suitable for languages like SQL, or is it just there for
historical reasons?

Best,
David.
-- 
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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Commits

  1. Use perfect hashing, instead of binary search, for keyword lookup.

  2. Reduce the size of the fmgr_builtin_oid_index[] array.

  3. Replace the data structure used for keyword lookup.