Unix Technical Forum

pgsql: Fix an error in make_outerjoininfo introduced by my patch of

This is a discussion on pgsql: Fix an error in make_outerjoininfo introduced by my patch of within the pgsql Committers forums, part of the PostgreSQL category; --> Log Message: ----------- Fix an error in make_outerjoininfo introduced by my patch of 30-Aug: the code neglected to test ...


Go Back   Unix Technical Forum > Database Server Software > PostgreSQL > pgsql Committers

FAQ Members List Calendar Search Today's Posts Mark Forums Read
  #1 (permalink)  
Old 04-11-2008, 01:50 AM
Tom Lane
 
Posts: n/a
Default pgsql: Fix an error in make_outerjoininfo introduced by my patch of

Log Message:
-----------
Fix an error in make_outerjoininfo introduced by my patch of 30-Aug: the code
neglected to test whether an outer join's join-condition actually refers to
the lower outer join it is looking at. (The comment correctly described what
was supposed to happen, but the code didn't do it...) This often resulted in
adding an unnecessary constraint on the join order of the two outer joins,
which was bad enough. However, it also seems to expose a performance
problem in an older patch (from 15-Feb): once we've decided that there is a
join ordering constraint, we will start trying clauseless joins between every
combination of rels within the constraint, which pointlessly eats up lots of
time and space if there are numerous rels below the outer join. That probably
needs to be revisited :-(. Per gripe from Jakub Ouhrabka.

Modified Files:
--------------
pgsql/src/backend/optimizer/plan:
initsplan.c (r1.134 -> r1.135)
(http://developer.postgresql.org/cvsw...1.134&r2=1.135)

---------------------------(end of broadcast)---------------------------
TIP 3: Have you checked our extensive FAQ?

http://www.postgresql.org/docs/faq

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On
Forum Jump


All times are GMT. The time now is 09:59 PM.


Powered by vBulletin® Version 3.6.5
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.2.0
www.UnixAdminTalk.com