Fix statistics reporting in logical replication workers

This new arrangement ensures that statistics are reported right after
commit of transactions.  The previous arrangement didn't get this quite
right and could lead to assertion failures.

Author: Petr Jelinek <petr.jelinek@2ndquadrant.com>
Reported-by: Erik Rijkers <er@xs4all.nl>

diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 0823000f001b4dbabf1a1672dc7c6e28d0b42a61..7e51076b376d9fbb9e3c0eb955aeef26afe04a88 100644 (file)
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -274,6 +274,7 @@ process_syncing_tables_for_apply(XLogRecPtr current_lsn)
        static List *table_states = NIL;
        static HTAB *last_start_times = NULL;
        ListCell   *lc;
+       bool            started_tx = false;
 
        Assert(!IsTransactionState());
 
@@ -290,6 +291,7 @@ process_syncing_tables_for_apply(XLogRecPtr current_lsn)
                table_states = NIL;
 
                StartTransactionCommand();
+               started_tx = true;
 
                /* Fetch all non-ready tables. */
                rstates = GetSubscriptionNotReadyRelations(MySubscription->oid);
@@ -304,8 +306,6 @@ process_syncing_tables_for_apply(XLogRecPtr current_lsn)
                }
                MemoryContextSwitchTo(oldctx);
 
-               CommitTransactionCommand();
-
                table_states_valid = true;
        }
 
@@ -350,11 +350,14 @@ process_syncing_tables_for_apply(XLogRecPtr current_lsn)
                        {
                                rstate->state = SUBREL_STATE_READY;
                                rstate->lsn = current_lsn;
-                               StartTransactionCommand();
+                               if (!started_tx)
+                               {
+                                       StartTransactionCommand();
+                                       started_tx = true;
+                               }
                                SetSubscriptionRelState(MyLogicalRepWorker->subid,
                                                                                rstate->relid, rstate->state,
                                                                                rstate->lsn);
-                               CommitTransactionCommand();
                        }
                }
                else
@@ -457,6 +460,12 @@ process_syncing_tables_for_apply(XLogRecPtr current_lsn)
                        }
                }
        }
+
+       if (started_tx)
+       {
+               CommitTransactionCommand();
+               pgstat_report_stat(false);
+       }
 }
 
 /*
@@ -806,6 +815,7 @@ LogicalRepSyncTableStart(XLogRecPtr *origin_startpos)
                                                                                MyLogicalRepWorker->relstate,
                                                                                MyLogicalRepWorker->relstate_lsn);
                                CommitTransactionCommand();
+                               pgstat_report_stat(false);
 
                                /*
                                 * We want to do the table data sync in single

diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index 2d7770d4dc1502db71e338a72701c8b60b371f1c..a61240ceee7d3719316926664024c5e9bf9b9fa8 100644 (file)
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -453,6 +453,7 @@ apply_handle_commit(StringInfo s)
                replorigin_session_origin_timestamp = commit_data.committime;
 
                CommitTransactionCommand();
+               pgstat_report_stat(false);
 
                store_flush_position(commit_data.end_lsn);
        }
@@ -462,7 +463,6 @@ apply_handle_commit(StringInfo s)
        /* Process any tables that are being synchronized in parallel. */
        process_syncing_tables(commit_data.end_lsn);
 
-       pgstat_report_stat(false);
        pgstat_report_activity(STATE_IDLE, NULL);
 }