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pgsql: Prevent access to other sessions' empty temp tables
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* pgsql: Prevent access to other sessions' empty temp tables
@ 2026-07-03 15:01 Alexander Korotkov <akorotkov@postgresql.org>
  0 siblings, 0 replies; 5+ messages in thread

From: Alexander Korotkov @ 2026-07-03 15:01 UTC (permalink / raw)
  To: pgsql-committers@lists.postgresql.org

Prevent access to other sessions' empty temp tables

Commit ce146621 ensures that ERROR is raised if a session tries to read
pages of another session's temp table.  But there is a corner case where
the other session's temp table is empty -- in this case the INSERT
command bypasses our checks and executes without any errors.

Such behavior is inconsistent and erroneous: it leaves an invalid buffer
in the temp buffers pool.  Since the buffer was created for another
session's temp table, we get an error "no such file or directory" when
trying to flush it.

This commit fixes it by adding a RELATION_IS_OTHER_TEMP check in the
relation-extension path.

Backpatch to 16, because it is the first release after 31966b151e6, which
introduced a separate local relation extension function
ExtendBufferedRelLocal(), which lacks of RELATION_IS_OTHER_TEMP() check.
As this fix introduces more checks to 013_temp_obj_multisession.pl, backpatch
the whole test script to 16.

Discussion: https://postgr.es/m/CAJDiXgiX2XZBHDNo%2BzBbvku%2BtchrUurvPRaN1_40mEQ1_sG90g%40mail.gmail.com
Author: Daniil Davydov <3danissimo@gmail.com>
Reviewed-by: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Imran Zaheer <imran.zhir@gmail.com>
Reviewed-by: ZizhuanLiu X-MAN <44973863@qq.com>
Backpatch-through: 16

Branch
------
REL_18_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/3aaefe8924f4828eabd414bfda98793e769aed8e

Modified Files
--------------
src/backend/storage/buffer/bufmgr.c                      | 14 ++++++++++++++
src/include/utils/rel.h                                  |  8 ++++----
.../modules/test_misc/t/013_temp_obj_multisession.pl     | 16 ++++++++++++++++
3 files changed, 34 insertions(+), 4 deletions(-)



^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* pgsql: Prevent access to other sessions' empty temp tables
@ 2026-07-03 15:01 Alexander Korotkov <akorotkov@postgresql.org>
  0 siblings, 0 replies; 5+ messages in thread

From: Alexander Korotkov @ 2026-07-03 15:01 UTC (permalink / raw)
  To: pgsql-committers@lists.postgresql.org

Prevent access to other sessions' empty temp tables

Commit ce146621 ensures that ERROR is raised if a session tries to read
pages of another session's temp table.  But there is a corner case where
the other session's temp table is empty -- in this case the INSERT
command bypasses our checks and executes without any errors.

Such behavior is inconsistent and erroneous: it leaves an invalid buffer
in the temp buffers pool.  Since the buffer was created for another
session's temp table, we get an error "no such file or directory" when
trying to flush it.

This commit fixes it by adding a RELATION_IS_OTHER_TEMP check in the
relation-extension path.

Backpatch to 16, because it is the first release after 31966b151e6, which
introduced a separate local relation extension function
ExtendBufferedRelLocal(), which lacks of RELATION_IS_OTHER_TEMP() check.
As this fix introduces more checks to 013_temp_obj_multisession.pl, backpatch
the whole test script to 16.

Discussion: https://postgr.es/m/CAJDiXgiX2XZBHDNo%2BzBbvku%2BtchrUurvPRaN1_40mEQ1_sG90g%40mail.gmail.com
Author: Daniil Davydov <3danissimo@gmail.com>
Reviewed-by: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Imran Zaheer <imran.zhir@gmail.com>
Reviewed-by: ZizhuanLiu X-MAN <44973863@qq.com>
Backpatch-through: 16

Branch
------
REL_16_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/cc3fe7e2a7471c541df7ff168bc41a3435f61fb0

Modified Files
--------------
src/backend/storage/buffer/bufmgr.c                |  14 ++
.../test_misc/t/013_temp_obj_multisession.pl       | 274 +++++++++++++++++++++
2 files changed, 288 insertions(+)



^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* pgsql: Prevent access to other sessions' empty temp tables
@ 2026-07-03 15:01 Alexander Korotkov <akorotkov@postgresql.org>
  0 siblings, 0 replies; 5+ messages in thread

From: Alexander Korotkov @ 2026-07-03 15:01 UTC (permalink / raw)
  To: pgsql-committers@lists.postgresql.org

Prevent access to other sessions' empty temp tables

Commit ce146621 ensures that ERROR is raised if a session tries to read
pages of another session's temp table.  But there is a corner case where
the other session's temp table is empty -- in this case the INSERT
command bypasses our checks and executes without any errors.

Such behavior is inconsistent and erroneous: it leaves an invalid buffer
in the temp buffers pool.  Since the buffer was created for another
session's temp table, we get an error "no such file or directory" when
trying to flush it.

This commit fixes it by adding a RELATION_IS_OTHER_TEMP check in the
relation-extension path.

Backpatch to 16, because it is the first release after 31966b151e6, which
introduced a separate local relation extension function
ExtendBufferedRelLocal(), which lacks of RELATION_IS_OTHER_TEMP() check.
As this fix introduces more checks to 013_temp_obj_multisession.pl, backpatch
the whole test script to 16.

Discussion: https://postgr.es/m/CAJDiXgiX2XZBHDNo%2BzBbvku%2BtchrUurvPRaN1_40mEQ1_sG90g%40mail.gmail.com
Author: Daniil Davydov <3danissimo@gmail.com>
Reviewed-by: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Imran Zaheer <imran.zhir@gmail.com>
Reviewed-by: ZizhuanLiu X-MAN <44973863@qq.com>
Backpatch-through: 16

Branch
------
REL_17_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/4e49f68b72dea48b2f6772b66b7565b8f652291b

Modified Files
--------------
src/backend/storage/buffer/bufmgr.c                      | 14 ++++++++++++++
src/include/utils/rel.h                                  |  8 ++++----
.../modules/test_misc/t/013_temp_obj_multisession.pl     | 16 ++++++++++++++++
3 files changed, 34 insertions(+), 4 deletions(-)



^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* pgsql: Prevent access to other sessions' empty temp tables
@ 2026-07-03 15:02 Alexander Korotkov <akorotkov@postgresql.org>
  0 siblings, 0 replies; 5+ messages in thread

From: Alexander Korotkov @ 2026-07-03 15:02 UTC (permalink / raw)
  To: pgsql-committers@lists.postgresql.org

Prevent access to other sessions' empty temp tables

Commit ce146621 ensures that ERROR is raised if a session tries to read
pages of another session's temp table.  But there is a corner case where
the other session's temp table is empty -- in this case the INSERT
command bypasses our checks and executes without any errors.

Such behavior is inconsistent and erroneous: it leaves an invalid buffer
in the temp buffers pool.  Since the buffer was created for another
session's temp table, we get an error "no such file or directory" when
trying to flush it.

This commit fixes it by adding a RELATION_IS_OTHER_TEMP check in the
relation-extension path.

Backpatch to 16, because it is the first release after 31966b151e6, which
introduced a separate local relation extension function
ExtendBufferedRelLocal(), which lacks of RELATION_IS_OTHER_TEMP() check.
As this fix introduces more checks to 013_temp_obj_multisession.pl, backpatch
the whole test script to 16.

Discussion: https://postgr.es/m/CAJDiXgiX2XZBHDNo%2BzBbvku%2BtchrUurvPRaN1_40mEQ1_sG90g%40mail.gmail.com
Author: Daniil Davydov <3danissimo@gmail.com>
Reviewed-by: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Imran Zaheer <imran.zhir@gmail.com>
Reviewed-by: ZizhuanLiu X-MAN <44973863@qq.com>
Backpatch-through: 16

Branch
------
REL_19_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/8021cdceb0186d3e0fb2c56ffef9ece46840a7e3

Modified Files
--------------
src/backend/storage/buffer/bufmgr.c                      | 14 ++++++++++++++
src/include/utils/rel.h                                  |  8 ++++----
.../modules/test_misc/t/013_temp_obj_multisession.pl     | 16 ++++++++++++++++
3 files changed, 34 insertions(+), 4 deletions(-)



^ permalink  raw  reply  [nested|flat] 5+ messages in thread

* pgsql: Prevent access to other sessions' empty temp tables
@ 2026-07-03 15:02 Alexander Korotkov <akorotkov@postgresql.org>
  0 siblings, 0 replies; 5+ messages in thread

From: Alexander Korotkov @ 2026-07-03 15:02 UTC (permalink / raw)
  To: pgsql-committers@lists.postgresql.org

Prevent access to other sessions' empty temp tables

Commit ce146621 ensures that ERROR is raised if a session tries to read
pages of another session's temp table.  But there is a corner case where
the other session's temp table is empty -- in this case the INSERT
command bypasses our checks and executes without any errors.

Such behavior is inconsistent and erroneous: it leaves an invalid buffer
in the temp buffers pool.  Since the buffer was created for another
session's temp table, we get an error "no such file or directory" when
trying to flush it.

This commit fixes it by adding a RELATION_IS_OTHER_TEMP check in the
relation-extension path.

Backpatch to 16, because it is the first release after 31966b151e6, which
introduced a separate local relation extension function
ExtendBufferedRelLocal(), which lacks of RELATION_IS_OTHER_TEMP() check.
As this fix introduces more checks to 013_temp_obj_multisession.pl, backpatch
the whole test script to 16.

Discussion: https://postgr.es/m/CAJDiXgiX2XZBHDNo%2BzBbvku%2BtchrUurvPRaN1_40mEQ1_sG90g%40mail.gmail.com
Author: Daniil Davydov <3danissimo@gmail.com>
Reviewed-by: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Imran Zaheer <imran.zhir@gmail.com>
Reviewed-by: ZizhuanLiu X-MAN <44973863@qq.com>
Backpatch-through: 16

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/c40819ebf954eefe8ec35c210b8a3d7a7a7aaea0

Modified Files
--------------
src/backend/storage/buffer/bufmgr.c                      | 14 ++++++++++++++
src/include/utils/rel.h                                  |  8 ++++----
.../modules/test_misc/t/013_temp_obj_multisession.pl     | 16 ++++++++++++++++
3 files changed, 34 insertions(+), 4 deletions(-)



^ permalink  raw  reply  [nested|flat] 5+ messages in thread


end of thread, other threads:[~2026-07-03 15:02 UTC | newest]

Thread overview: 5+ messages (download: mbox mbox.gz follow: Atom feed)
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2026-07-03 15:01 pgsql: Prevent access to other sessions' empty temp tables Alexander Korotkov <akorotkov@postgresql.org>
2026-07-03 15:01 pgsql: Prevent access to other sessions' empty temp tables Alexander Korotkov <akorotkov@postgresql.org>
2026-07-03 15:01 pgsql: Prevent access to other sessions' empty temp tables Alexander Korotkov <akorotkov@postgresql.org>
2026-07-03 15:02 pgsql: Prevent access to other sessions' empty temp tables Alexander Korotkov <akorotkov@postgresql.org>
2026-07-03 15:02 pgsql: Prevent access to other sessions' empty temp tables Alexander Korotkov <akorotkov@postgresql.org>

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