Обсуждение: Bug in cursors??
Hi all, I came across this comment in exec_append_initialize_next.... /* ---------------- * initialize the scan * (and update the range table appropriately) * (doesn't this leave the range table hosed for anybody upstream * of the Append node??? - jolly ) * ---------------- */ I took a stab at guessing what this might mean, and ran the following test. It looks like a bug. Can anybody shed any light on whether the above comment is likely to relate to this bug, and is there anybody who is so intimate with this code that they are willing to fix it? # Comment: b and c inherit from a. d inherits from b. chrisb=# begin work; BEGIN chrisb=# select aa from a;aa ---- (0 rows) chrisb=# select aa from b;aa -----ppp (1 row) chrisb=# select aa from c; aa -------cmore (1 row) chrisb=# select aa from d; aa -------dmore (1 row) chrisb=# select aa from a*; aa -------pppcmoredmore (3 rows) chrisb=# declare cu cursor for select aa from a*; SELECT chrisb=# fetch forward 1 in cu;aa -----ppp (1 row) chrisb=# fetch forward 1 in cu; aa -------cmore (1 row) chrisb=# fetch backward 1 in cu;aa ---- (0 rows)
> -----Original Message-----
> From: owner-pgsql-hackers@postgreSQL.org
> [mailto:owner-pgsql-hackers@postgreSQL.org]On Behalf Of Chris Bitmead
>
> Hi all,
>
> I came across this comment in exec_append_initialize_next....
>
> /* ----------------
> * initialize the scan
> * (and update the range table appropriately)
> * (doesn't this leave the range table hosed for
> anybody upstream
> * of the Append node??? - jolly )
> * ----------------
> */
>
> I took a stab at guessing what this might mean, and ran the following
> test.
> It looks like a bug. Can anybody shed any light on whether the above
> comment is likely to relate to this bug, and is there anybody who is
> so intimate with this code that they are willing to fix it?
>
I've forgotten to apply the following patch.
Without the patch,backward sequential scan is impossible
after reaching EOF.
It may be one of the cause.
Regards.
*** access/heap/heapam.c.orig Mon Aug 2 14:56:36 1999
--- access/heap/heapam.c Tue Nov 9 12:59:48 1999
***************
*** 775,782 **** if (scan->rs_ptup.t_data == scan->rs_ctup.t_data &&
BufferIsInvalid(scan->rs_pbuf)) {
- if (BufferIsValid(scan->rs_nbuf))
- ReleaseBuffer(scan->rs_nbuf); return NULL; }
--- 775,780 ----
***************
*** 833,842 **** ReleaseBuffer(scan->rs_pbuf); scan->rs_ptup.t_data = NULL;
scan->rs_pbuf= InvalidBuffer;
- if (BufferIsValid(scan->rs_nbuf))
- ReleaseBuffer(scan->rs_nbuf);
- scan->rs_ntup.t_data = NULL;
- scan->rs_nbuf = InvalidBuffer; return NULL; }
--- 831,836 ----
***************
*** 855,862 **** if (scan->rs_ctup.t_data == scan->rs_ntup.t_data &&
BufferIsInvalid(scan->rs_nbuf)) {
- if (BufferIsValid(scan->rs_pbuf))
- ReleaseBuffer(scan->rs_pbuf); HEAPDEBUG_3; /* heap_getnext returns NULL at end */
return NULL; }
--- 849,854 ----
***************
*** 915,924 **** ReleaseBuffer(scan->rs_nbuf); scan->rs_ntup.t_data = NULL;
scan->rs_nbuf= InvalidBuffer;
- if (BufferIsValid(scan->rs_pbuf))
- ReleaseBuffer(scan->rs_pbuf);
- scan->rs_ptup.t_data = NULL;
- scan->rs_pbuf = InvalidBuffer; HEAPDEBUG_6; /* heap_getnext returning EOS */
return NULL; }
--- 907,912 ----
Hiroshi, do you need this applied?
>
> I've forgotten to apply the following patch.
> Without the patch,backward sequential scan is impossible
> after reaching EOF.
> It may be one of the cause.
>
> Regards.
>
> *** access/heap/heapam.c.orig Mon Aug 2 14:56:36 1999
> --- access/heap/heapam.c Tue Nov 9 12:59:48 1999
> ***************
> *** 775,782 ****
> if (scan->rs_ptup.t_data == scan->rs_ctup.t_data &&
> BufferIsInvalid(scan->rs_pbuf))
> {
> - if (BufferIsValid(scan->rs_nbuf))
> - ReleaseBuffer(scan->rs_nbuf);
> return NULL;
> }
>
> --- 775,780 ----
> ***************
> *** 833,842 ****
> ReleaseBuffer(scan->rs_pbuf);
> scan->rs_ptup.t_data = NULL;
> scan->rs_pbuf = InvalidBuffer;
> - if (BufferIsValid(scan->rs_nbuf))
> - ReleaseBuffer(scan->rs_nbuf);
> - scan->rs_ntup.t_data = NULL;
> - scan->rs_nbuf = InvalidBuffer;
> return NULL;
> }
>
> --- 831,836 ----
> ***************
> *** 855,862 ****
> if (scan->rs_ctup.t_data == scan->rs_ntup.t_data &&
> BufferIsInvalid(scan->rs_nbuf))
> {
> - if (BufferIsValid(scan->rs_pbuf))
> - ReleaseBuffer(scan->rs_pbuf);
> HEAPDEBUG_3; /* heap_getnext returns NULL at end */
> return NULL;
> }
> --- 849,854 ----
> ***************
> *** 915,924 ****
> ReleaseBuffer(scan->rs_nbuf);
> scan->rs_ntup.t_data = NULL;
> scan->rs_nbuf = InvalidBuffer;
> - if (BufferIsValid(scan->rs_pbuf))
> - ReleaseBuffer(scan->rs_pbuf);
> - scan->rs_ptup.t_data = NULL;
> - scan->rs_pbuf = InvalidBuffer;
> HEAPDEBUG_6; /* heap_getnext returning EOS */
> return NULL;
> }
> --- 907,912 ----
>
> ************
>
-- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610)
853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill,
Pennsylvania19026
> -----Original Message----- > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > Sent: Tuesday, February 08, 2000 6:16 PM > > Hiroshi, do you need this applied? > Oops,this patch is old,sorry. Another patch may be needed. DO you think this patch should also be applied to REL tree ? If so,could you please apply it to both trees ? Otherwise I would commit it only to current tree myself. Regards. Hiroshi Inoue Inoue@tpf.co.jp
[Charset iso-8859-1 unsupported, filtering to ASCII...] > > -----Original Message----- > > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > Sent: Tuesday, February 08, 2000 6:16 PM > > > > Hiroshi, do you need this applied? > > > > Oops,this patch is old,sorry. > Another patch may be needed. > > DO you think this patch should also be applied to REL tree ? > If so,could you please apply it to both trees ? > Otherwise I would commit it only to current tree myself. I don't think we are doing more 6.5.* releases -- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610) 853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania19026
> -----Original Message----- > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > [Charset iso-8859-1 unsupported, filtering to ASCII...] > > > -----Original Message----- > > > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > > Sent: Tuesday, February 08, 2000 6:16 PM > > > > > > Hiroshi, do you need this applied? > > > > > > > Oops,this patch is old,sorry. > > Another patch may be needed. > > > > DO you think this patch should also be applied to REL tree ? > > If so,could you please apply it to both trees ? > > Otherwise I would commit it only to current tree myself. > > I don't think we are doing more 6.5.* releases > OK,I have committed the patch to current tree. BTW I found the following TODO item. * update pg_class.relhasindex during vacuum when all indexes are dropped Seems vacuum has done so from the first. Regards. Hiroshi Inoue Inoue@tpf.co.jp
> > > If so,could you please apply it to both trees ? > > > Otherwise I would commit it only to current tree myself. > > > > I don't think we are doing more 6.5.* releases > > > > OK,I have committed the patch to current tree. > > BTW I found the following TODO item. > * update pg_class.relhasindex during vacuum when all indexes are dropped > > Seems vacuum has done so from the first. Yes, I see. TODO updated. -- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610) 853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania19026