Andres Freund <and...@2ndquadrant.com> writes: > On 2012-12-20 23:12:55 +0000, McDevitt, Charles wrote: >>> Another way of attack along these lines might be to use the %glr-parser >>> and then try to cut back on all those redundant rules that were put in >>> to avoid conflicts. The number of key words categories and such could >>> perhaps also be reduced that way.
>> The GLR output from Bison is licensed under the GPL (unlike the LALR output). >> So using Bison's GLR mode isn't an option. > Thats not the case anymore: > http://www.gnu.org/software/bison/manual/html_node/Conditions.html This does mean that we'd have to specify a minimum bison version of 2.2 in order to be squeaky-clean license wise, if we went over to using the GLR mode. However, that would likely be a good idea anyway from a technical standpoint --- the GLR mode may exist in ancient bison versions, but who knows how bug-free it is. Anyway, this is all merest speculation until somebody actually tries it and sees if a performance gain is possible. Having just re-read the description of GLR mode, I wouldn't be surprised if any savings in table size is squandered by its handling of ambiguous cases (ie, the need to track and merge multiple parser states). regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
