v4-0012-fixup-add-proper-schema-tracking.patch

From 13f056ac3452588e6f8e3e832f222f3f6416857f Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Fri, 27 Dec 2019 23:56:04 +0100
Subject: [PATCH v4 12/19] fixup: add proper schema tracking

---
 src/backend/replication/pgoutput/pgoutput.c | 45 +++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 8490ea4..0148f4c 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -82,6 +82,8 @@ typedef struct RelationSyncEntry
 	Oid			relid;			/* relation oid */
 	TransactionId	xid;		/* transaction that created the record */
 	bool		schema_sent;	/* did we send the schema? */
+	List	   *streamed_txns;	/* streamed toplevel transactions with
+								 * this schema */
 	bool		replicate_valid;
 	PublicationActions pubactions;
 } RelationSyncEntry;
@@ -96,6 +98,11 @@ static void rel_sync_cache_relation_cb(Datum arg, Oid relid);
 static void rel_sync_cache_publication_cb(Datum arg, int cacheid,
 										  uint32 hashvalue);
 
+static void set_schema_sent_in_streamed_txn(RelationSyncEntry *entry,
+											TransactionId xid);
+static bool get_schema_sent_in_streamed_txn(RelationSyncEntry *entry,
+											TransactionId xid);
+
 /*
  * Specify output plugin callbacks
  */
@@ -366,6 +373,7 @@ maybe_send_schema(LogicalDecodingContext *ctx,
 {
 	bool	schema_sent;
 	TransactionId xid = InvalidTransactionId;
+	TransactionId topxid = InvalidTransactionId;
 
 	/*
 	 * Remember XID of the (sub)transaction for the change. We don't care if
@@ -378,6 +386,11 @@ maybe_send_schema(LogicalDecodingContext *ctx,
 	if (in_streaming)
 		xid = change->txn->xid;
 
+	if (change->txn->toptxn)
+		topxid = change->txn->toptxn->xid;
+	else
+		topxid = xid;
+
 	/*
 	 * Do we need to send the schema? We do track streamed transactions
 	 * separately, because those may not be applied later (and the regular
@@ -391,7 +404,7 @@ maybe_send_schema(LogicalDecodingContext *ctx,
 		 * occur when streaming already started, so we have to track new catalog
 		 * changes somehow.
 		 */
-		schema_sent = txn->is_schema_sent;
+		schema_sent = get_schema_sent_in_streamed_txn(relentry, topxid);
 	}
 	else
 		schema_sent = relentry->schema_sent;
@@ -432,7 +445,7 @@ maybe_send_schema(LogicalDecodingContext *ctx,
 		relentry->xid = change->txn->xid;
 
 		if (in_streaming)
-			txn->is_schema_sent = true;
+			set_schema_sent_in_streamed_txn(relentry, topxid);
 		else
 			relentry->schema_sent = true;
 	}
@@ -760,6 +773,34 @@ init_rel_sync_cache(MemoryContext cachectx)
 }
 
 /*
+ * We expect relatively small number of streamed transactions.
+ */
+static bool
+get_schema_sent_in_streamed_txn(RelationSyncEntry *entry, TransactionId xid)
+{
+	ListCell *lc;
+	foreach (lc, entry->streamed_txns)
+	{
+		if (xid == lfirst_int(lc))
+			return true;
+	}
+
+	return false;
+}
+
+static void
+set_schema_sent_in_streamed_txn(RelationSyncEntry *entry, TransactionId xid)
+{
+	MemoryContext	oldctx;
+
+	oldctx = MemoryContextSwitchTo(CacheMemoryContext);
+
+	entry->streamed_txns = lappend_int(entry->streamed_txns, xid);
+
+	MemoryContextSwitchTo(oldctx);
+}
+
+/*
  * Find or create entry in the relation schema cache.
  */
 static RelationSyncEntry *
-- 
1.8.3.1