Fix assertion failures while processing NEW_CID record in logical decoding.

When the logical decoding restarts from NEW_CID, since there is no
association between the top transaction and its subtransaction, both are
created as top transactions and have the same LSN. This caused the
assertion failure in AssertTXNLsnOrder().

This patch skips the assertion check until we reach the LSN at which we
start decoding the contents of the transaction, specifically
start_decoding_at LSN in SnapBuild. This is okay because we don't
guarantee to make the association between top transaction and
subtransaction until we try to decode the actual contents of transaction.
The ordering of the records prior to the start_decoding_at LSN should have
been checked before the restart.

The other assertion failure is due to the reason that we forgot to track
that we have considered top-level transaction id in the list of catalog
changing transactions that were committed when one of its subtransactions
is marked as containing catalog change.

Reported-by: Tomas Vondra, Osumi Takamichi
Author: Masahiko Sawada, Kuroda Hayato
Reviewed-by: Amit Kapila, Dilip Kumar, Kuroda Hayato, Kyotaro Horiguchi, Masahiko Sawada
Backpatch-through: 10
Discussion: https://postgr.es/m/a89b46b6-0239-2fd5-71a9-b19b1f7a7145%40enterprisedb.com
Discussion: https://postgr.es/m/TYCPR01MB83733C6CEAE47D0280814D5AED7A9%40TYCPR01MB8373.jpnprd01.prod.outlook.com

1 files changed, 16 insertions, 0 deletions

diff --git a/contrib/test_decoding/specs/catalog_change_snapshot.spec b/contrib/test_decoding/specs/catalog_change_snapshot.spec
index ff8f68489bb..673bccf4b0d 100644
--- a/contrib/test_decoding/specs/catalog_change_snapshot.spec
+++ b/contrib/test_decoding/specs/catalog_change_snapshot.spec
@@ -6,12 +6,14 @@ setup
     DROP TABLE IF EXISTS tbl2;
     CREATE TABLE tbl1 (val1 integer, val2 integer);
     CREATE TABLE tbl2 (val1 integer, val2 integer);
+    CREATE TABLE user_cat (val1 integer) WITH (user_catalog_table = true);
 }
 
 teardown
 {
     DROP TABLE tbl1;
     DROP TABLE tbl2;
+    DROP TABLE user_cat;
     SELECT 'stop' FROM pg_drop_replication_slot('isolation_slot');
 }
 
@@ -22,6 +24,7 @@ step "s0_begin" { BEGIN; }
 step "s0_savepoint" { SAVEPOINT sp1; }
 step "s0_truncate" { TRUNCATE tbl1; }
 step "s0_insert" { INSERT INTO tbl1 VALUES (1); }
+step "s0_insert2" { INSERT INTO user_cat VALUES (1); }
 step "s0_commit" { COMMIT; }
 
 session "s1"
@@ -57,3 +60,16 @@ permutation "s0_init" "s0_begin" "s0_savepoint" "s0_truncate" "s1_checkpoint" "s
 # checkpoint record it prunes one of the xacts in that list and when decoding the
 # next checkpoint, it will completely prune that list.
 permutation "s0_init" "s0_begin" "s0_truncate" "s2_begin" "s2_truncate" "s1_checkpoint" "s1_get_changes" "s0_commit" "s0_begin" "s0_insert" "s1_checkpoint" "s1_get_changes" "s2_commit" "s1_checkpoint" "s1_get_changes" "s0_commit" "s1_get_changes"
+
+# Test that we can handle the case where there is no association between top-level
+# transaction and its subtransactions. The last decoding restarts from the first
+# checkpoint, decodes NEW_CID generated by "s0_insert2", and marks the subtransaction
+# as containing catalog changes while adding tuple cids to its top-level transaction.
+# During that, both transaction entries are created in ReorderBuffer as top-level
+# transactions and have the same LSN. We check if the assertion check for the order
+# of transaction LSNs in AssertTXNLsnOrder() is skipped since we are still before the
+# LSN at which we start replaying the contents of transactions. Besides, when decoding
+# the commit record of the top-level transaction, we must force the top-level
+# transaction to do timetravel since one of its subtransactions has been marked as
+# containing catalog changes.
+permutation "s0_init" "s0_begin" "s0_savepoint" "s0_insert" "s1_checkpoint" "s1_get_changes" "s0_insert2" "s0_commit" "s0_begin" "s0_insert" "s1_checkpoint" "s1_get_changes" "s0_commit" "s1_get_changes"