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 <[email protected]> Reviewed-by: Jim Jones <[email protected]> Reviewed-by: Imran Zaheer <[email protected]> Reviewed-by: ZizhuanLiu X-MAN <[email protected]> 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(-)
