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| author | Amit Kapila <akapila@postgresql.org> | 2021-03-01 08:14:33 +0530 |
|---|---|---|
| committer | Amit Kapila <akapila@postgresql.org> | 2021-03-01 08:14:33 +0530 |
| commit | b4e3dc7fd420cdc2287f30a638c4affd071f01b2 (patch) | |
| tree | 9b16c0843a81482506e2e4ce4afca9d06ce610d9 /doc/src/sgml/logicaldecoding.sgml | |
| parent | 6148656a0be1c6245fbcfcbbeb87541f1b173162 (diff) | |
| download | postgresql-b4e3dc7fd420cdc2287f30a638c4affd071f01b2.tar.gz postgresql-b4e3dc7fd420cdc2287f30a638c4affd071f01b2.zip | |
Update the docs and comments for decoding of prepared xacts.
Commit a271a1b50e introduced decoding at prepare time in ReorderBuffer.
This can lead to deadlock for out-of-core logical replication solutions
that uses this feature to build distributed 2PC in case such transactions
lock [user] catalog tables exclusively. They need to inform users to not
have locks on catalog tables (via explicit LOCK command) in such
transactions.
Reported-by: Andres Freund
Discussion: https://postgr.es/m/20210222222847.tpnb6eg3yiykzpky@alap3.anarazel.de
Diffstat (limited to 'doc/src/sgml/logicaldecoding.sgml')
| -rw-r--r-- | doc/src/sgml/logicaldecoding.sgml | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/doc/src/sgml/logicaldecoding.sgml b/doc/src/sgml/logicaldecoding.sgml index 6455664cb4f..85c55d64125 100644 --- a/doc/src/sgml/logicaldecoding.sgml +++ b/doc/src/sgml/logicaldecoding.sgml @@ -1228,5 +1228,29 @@ stream_commit_cb(...); <-- commit of the streamed transaction that name pattern will not be decoded as a two-phase commit transaction. </para> + <para> + The users that want to decode prepared transactions need to be careful about + below mentioned points: + + <itemizedlist> + <listitem> + <para> + If the prepared transaction has locked [user] catalog tables exclusively + then decoding prepare can block till the main transaction is committed. + </para> + </listitem> + + <listitem> + <para> + The logical replication solution that builds distributed two phase commit + using this feature can deadlock if the prepared transaction has locked + [user] catalog tables exclusively. They need to inform users to not have + locks on catalog tables (via explicit <command>LOCK</command> command) in + such transactions. + </para> + </listitem> + </itemizedlist> + </para> + </sect1> </chapter> |