Hi Rafael, Try disabling the prepare statement processing in DBD::Pg and try the timing runs again. Regards, Ken On Wed, Mar 21, 2012 at 12:21:23PM +0100, Rafael Martinez wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hello > > We are having some performance problems with an application that uses > prepared statement heavily. > > We have found out that it creates-executes-destroys a prepared statement > *per* statement it sends to the database (pg-9.1) via DBD-Pg. > > A normal log entry for a sql-statement looks e.g. like this: > - ---------------------------------------------------------- > [2012-03-15 14:49:12.484 CET] LOG: duration: 8.440 ms parse > dbdpg_p32048_3: > > SELECT DISTINCT ACL.RightName FROM ACL, Principals, CachedGroupMembers > WHERE Principals.id = ACL.PrincipalId AND Principals.PrincipalType = > 'Group' AND Principals.Disabled = 0 AND CachedGroupMembers.GroupId = > ACL.PrincipalId AND CachedGroupMembers.GroupId = Principals.id AND > CachedGroupMembers.MemberId = 19312 AND CachedGroupMembers.Disabled = 0 > AND ((ACL.ObjectType = 'RT::System' AND ACL.ObjectId = 1) OR > (ACL.ObjectType = 'RT::System' AND ACL.ObjectId = 1)) > > [2012-03-15 14:49:12.485 CET] LOG: duration: 0.087 ms bind > dbdpg_p32048_3: > > SELECT DISTINCT ACL.RightName FROM ACL, Principals, CachedGroupMembers > WHERE Principals.id = ACL.PrincipalId AND Principals.PrincipalType = > 'Group' AND Principals.Disabled = 0 AND CachedGroupMembers.GroupId = > ACL.PrincipalId AND CachedGroupMembers.GroupId = Principals.id AND > CachedGroupMembers.MemberId = 19312 AND CachedGroupMembers.Disabled = 0 > AND ((ACL.ObjectType = 'RT::System' AND ACL.ObjectId = 1) OR > (ACL.ObjectType = 'RT::System' AND ACL.ObjectId = 1)) > > > [2012-03-15 14:49:12.487 CET] LOG: duration: 1.692 ms execute > dbdpg_p32048_3: > > SELECT DISTINCT ACL.RightName FROM ACL, Principals, CachedGroupMembers > WHERE Principals.id = ACL.PrincipalId AND Principals.PrincipalType = > 'Group' AND Principals.Disabled = 0 AND CachedGroupMembers.GroupId = > ACL.PrincipalId AND CachedGroupMembers.GroupId = Principals.id AND > CachedGroupMembers.MemberId = 19312 AND CachedGroupMembers.Disabled = 0 > AND ((ACL.ObjectType = 'RT::System' AND ACL.ObjectId = 1) OR > (ACL.ObjectType = 'RT::System' AND ACL.ObjectId = 1)) > > > [2012-03-15 14:49:12.488 CET] LOG: duration: 0.029 ms statement: > DEALLOCATE dbdpg_p32048_3 > - ---------------------------------------------------------- > > As you can see, the parse+bind+deallocate part uses much more time than > the execution part. This is the same for many of the statements send to > the database. > > My question is: > > Is the parse+bind time reported, a time (not reported) that the planer > will use anyway when running a sql-statement in a normal way or the > parse+bind+deallocate time is *extra* time needed by the prepared statement? > > Can we assume that running this application without using prepared > statements will do that it runs faster the time used by > parse+bind+deallocate? > > Thanks in advance. > > regards, > - -- > Rafael Martinez Guerrero > Center for Information Technology > University of Oslo, Norway > > PGP Public Key: http://folk.uio.no/rafael/ > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.10 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ > > iEYEARECAAYFAk9pubAACgkQBhuKQurGihTYkwCcCFYQRDGWD0yaR+f2FFwKs7gN > RfgAoJdPrAzUhfBfsXmst7/l7LVLisHy > =l7Fl > -----END PGP SIGNATURE----- > > -- > Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
