On 2 March 2013 18:47, Heikki Linnakangas <hlinnakan...@vmware.com> wrote:
>> Uh ... no. I haven't looked into why the flex tables are so large, >> but this theory is just wrong. See ScanKeywordLookup(). > > > Interestingly, the yy_transition array generated by flex used to be much > smaller: > > 8.3: 22072 elements > 8.4: 62623 elements > master: 64535 elements > > The big jump between 8.3 and 8.4 was caused by introduction of the unicode > escapes: U&'foo' [UESCAPE 'x'] . And in particular, the "error rule" for the > UESCAPE, which we use to avoid backtracking. > > I experimented with a patch that uses two extra flex states to shorten the > error rules, see attached. The idea is that after lexing a unicode literal > like "U&'foo'", you enter a new state, in which you check whether an > "UESCAPE 'x'" follows. This slashes the size of the array to 36581 elements. +1 to do this sooner rather than later -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
