Thread

1. Maximum query string length

   Ansley, Michael <michael.ansley@intec.co.za> — 1999-07-22T09:18:53Z

   Massimo wrote:
   >> A better way would be to allocate and grow query buffers dynamically
   while
   >> reading the query but you will anyway have troubles with lex and yacc
   which
   >> use statically allocated buffers whose size is hardwired in the program.
   >> This is why I had to make those ugly changes in the Makefiles.
   
   Well, if the query length is limited by yacc, bison, lex, or any other tools
   that we use, is it worthwhile trying to make it dynamic?  If I can still
   only get a 64k query into the backend, what use is there in creating a 800k
   query in psql?
   
   Thought and/or bright ideas or welcomed...
   
   
   MikeA
   
   
   

2. Re: [HACKERS] Maximum query string length

   Mark Hollomon <mhh@nortelnetworks.com> — 1999-07-22T12:39:28Z

   Ansley, Michael wrote:
   > 
   > Massimo wrote:
   > >> A better way would be to allocate and grow query buffers dynamically
   > while
   > >> reading the query but you will anyway have troubles with lex and yacc
   > which
   > >> use statically allocated buffers whose size is hardwired in the program.
   > >> This is why I had to make those ugly changes in the Makefiles.
   > 
   > Well, if the query length is limited by yacc, bison, lex, or any other tools
   > that we use, is it worthwhile trying to make it dynamic?  If I can still
   > only get a 64k query into the backend, what use is there in creating a 800k
   > query in psql?
   > 
   > Thought and/or bright ideas or welcomed...
   > 
   > MikeA
   
   That shouldn't be hard to fix. Though it might be hard to fix with good
   performance. The default input routines in lex fill its internal buffer
   with
   a 'line' of text. But all those routines can be overridden. So you could
   make lex read directly from the dynamic buffer. Look at yyinput (or is
   it yy_input - can't remember).
   
   If you do that, I think the only limitation will be on the size of a
   single token. I don't know how postgresql handles quoted text and
   comments,
   but that would be where the problem may arise.
   
   -- 
   
   Mark Hollomon
   mhh@nortelnetworks.com
   ESN 451-9008 (302)454-9008