Thread: execute command tag including affected rows count
Would it be possible to have the command completion tag for EXECUTE return the affected row count? The JDBC API says you should be able to get the affected row count for any statement and I'm working on integrating a patch that transforms regular statements to server side prepared statements, and I'm stuck on this issue. CREATE TABLE t (a int); INSERT INTO t VALUES (1); INSERT INTO t VALUES (2); PREPARE mystatement AS DELETE FROM t; EXECUTE mystatement; would ideally return "EXECUTE 2" Kris Jurka
On 21-Mar-04, at 11:39 AM, Kris Jurka wrote: > Would it be possible to have the command completion tag for EXECUTE > return > the affected row count? Yes, this has been suggested before -- for example: http://www.mail-archive.com/pgsql-hackers@postgresql.org/msg26787.html I agree it would be a good idea, although I can't recall what the conclusion of the previous discussions was -- did anyone raise any critical objections to this? -Neil
Neil Conway <neilc@samurai.com> writes: > On 21-Mar-04, at 11:39 AM, Kris Jurka wrote: >> Would it be possible to have the command completion tag for EXECUTE >> return >> the affected row count? > Yes, this has been suggested before -- for example: > http://www.mail-archive.com/pgsql-hackers@postgresql.org/msg26787.html > I agree it would be a good idea, although I can't recall what the > conclusion of the previous discussions was -- did anyone raise any > critical objections to this? The previous discussion concluded that EXECUTE should return the command tag of the executed command --- eg, "UPDATE n" not "EXECUTE n". Without this, you cannot for example sensibly cope with both the INSERT and UPDATE tag formats. Not sure what it takes internally to the backend to make this happen ... but IIRC there already is provision for utility commands to override their default tag, so I hope that it would be a pretty localized change. However, does this really solve Kris' problem? JDBC generally likes to think that it works with old Postgres versions; will a fix that only works in >= 7.5 be good enough for them? regards, tom lane
On Sun, 21 Mar 2004, Tom Lane wrote: > > On 21-Mar-04, at 11:39 AM, Kris Jurka wrote: > >> Would it be possible to have the command completion tag for EXECUTE > >> return > >> the affected row count? > > However, does this really solve Kris' problem? JDBC generally likes to > think that it works with old Postgres versions; will a fix that only > works in >= 7.5 be good enough for them? > I oversimplified the description of the current patch I'm working on, server side prepared statement support has been in the driver since the 7.3 days. So this problem already exists and has simply been unnoticed. With the current code it is difficult to enable server prepared statements and requires writing pg specific code outside of the standard JDBC API. The patch I'm reviewing makes it simple to turn on server prepared statements globally and brought this bug to my attention. I would say "better late than never." Kris Jurka
Neil Conway wrote: > On 21-Mar-04, at 11:39 AM, Kris Jurka wrote: > > Would it be possible to have the command completion tag for EXECUTE > > return > > the affected row count? > > Yes, this has been suggested before -- for example: > > http://www.mail-archive.com/pgsql-hackers@postgresql.org/msg26787.html > > I agree it would be a good idea, although I can't recall what the > conclusion of the previous discussions was -- did anyone raise any > critical objections to this? Should this be a TODO? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073