Add decoding of sequences to built-in replication

This commit adds support for decoding of sequences to the built-in
replication (the infrastructure was added by commit 0da92dc530).

The syntax and behavior mostly mimics handling of tables, i.e. a
publication may be defined as FOR ALL SEQUENCES (replicating all
sequences in a database), FOR ALL SEQUENCES IN SCHEMA (replicating
all sequences in a particular schema) or individual sequences.

To publish sequence modifications, the publication has to include
'sequence' action. The protocol is extended with a new message,
describing sequence increments.

A new system view pg_publication_sequences lists all the sequences
added to a publication, both directly and indirectly. Various psql
commands (\d and \dRp) are improved to also display publications
including a given sequence, or sequences included in a publication.

Author: Tomas Vondra, Cary Huang
Reviewed-by: Peter Eisentraut, Amit Kapila, Hannu Krosing, Andres
             Freund, Petr Jelinek
Discussion: https://postgr.es/m/[email protected]
Discussion: https://postgr.es/m/[email protected]

1 files changed, 74 insertions, 5 deletions

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 5fddab3a3d4..4cdc698cbb3 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -15,6 +15,7 @@
 #include "access/tupconvert.h"
 #include "catalog/partition.h"
 #include "catalog/pg_publication.h"
+#include "catalog/pg_publication_namespace.h"
 #include "catalog/pg_publication_rel.h"
 #include "commands/defrem.h"
 #include "executor/executor.h"
@@ -53,6 +54,10 @@ static void pgoutput_message(LogicalDecodingContext *ctx,
 							 ReorderBufferTXN *txn, XLogRecPtr message_lsn,
 							 bool transactional, const char *prefix,
 							 Size sz, const char *message);
+static void pgoutput_sequence(LogicalDecodingContext *ctx,
+							  ReorderBufferTXN *txn, XLogRecPtr sequence_lsn,
+							  Relation relation, bool transactional,
+							  int64 last_value, int64 log_cnt, bool is_called);
 static bool pgoutput_origin_filter(LogicalDecodingContext *ctx,
 								   RepOriginId origin_id);
 static void pgoutput_begin_prepare_txn(LogicalDecodingContext *ctx,
@@ -208,6 +213,7 @@ _PG_output_plugin_init(OutputPluginCallbacks *cb)
 	cb->change_cb = pgoutput_change;
 	cb->truncate_cb = pgoutput_truncate;
 	cb->message_cb = pgoutput_message;
+	cb->sequence_cb = pgoutput_sequence;
 	cb->commit_cb = pgoutput_commit_txn;
 
 	cb->begin_prepare_cb = pgoutput_begin_prepare_txn;
@@ -224,6 +230,7 @@ _PG_output_plugin_init(OutputPluginCallbacks *cb)
 	cb->stream_commit_cb = pgoutput_stream_commit;
 	cb->stream_change_cb = pgoutput_change;
 	cb->stream_message_cb = pgoutput_message;
+	cb->stream_sequence_cb = pgoutput_sequence;
 	cb->stream_truncate_cb = pgoutput_truncate;
 	/* transaction streaming - two-phase commit */
 	cb->stream_prepare_cb = pgoutput_stream_prepare_txn;
@@ -237,6 +244,7 @@ parse_output_parameters(List *options, PGOutputData *data)
 	bool		publication_names_given = false;
 	bool		binary_option_given = false;
 	bool		messages_option_given = false;
+	bool		sequences_option_given = false;
 	bool		streaming_given = false;
 	bool		two_phase_option_given = false;
 
@@ -244,6 +252,7 @@ parse_output_parameters(List *options, PGOutputData *data)
 	data->streaming = false;
 	data->messages = false;
 	data->two_phase = false;
+	data->sequences = true;
 
 	foreach(lc, options)
 	{
@@ -312,6 +321,16 @@ parse_output_parameters(List *options, PGOutputData *data)
 
 			data->messages = defGetBoolean(defel);
 		}
+		else if (strcmp(defel->defname, "sequences") == 0)
+		{
+			if (sequences_option_given)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			sequences_option_given = true;
+
+			data->sequences = defGetBoolean(defel);
+		}
 		else if (strcmp(defel->defname, "streaming") == 0)
 		{
 			if (streaming_given)
@@ -1440,6 +1459,51 @@ pgoutput_message(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 	OutputPluginWrite(ctx, true);
 }
 
+static void
+pgoutput_sequence(LogicalDecodingContext *ctx,
+				  ReorderBufferTXN *txn, XLogRecPtr sequence_lsn,
+				  Relation relation, bool transactional,
+				  int64 last_value, int64 log_cnt, bool is_called)
+{
+	PGOutputData *data = (PGOutputData *) ctx->output_plugin_private;
+	TransactionId xid = InvalidTransactionId;
+	RelationSyncEntry *relentry;
+
+	if (!data->sequences)
+		return;
+
+	if (!is_publishable_relation(relation))
+		return;
+
+	/*
+	 * Remember the xid for the message in streaming mode. See
+	 * pgoutput_change.
+	 */
+	if (in_streaming)
+		xid = txn->xid;
+
+	relentry = get_rel_sync_entry(data, relation);
+
+	/*
+	 * First check the sequence filter.
+	 *
+	 * We handle just REORDER_BUFFER_CHANGE_SEQUENCE here.
+	 */
+	if (!relentry->pubactions.pubsequence)
+		return;
+
+	OutputPluginPrepareWrite(ctx, true);
+	logicalrep_write_sequence(ctx->out,
+							  relation,
+							  xid,
+							  sequence_lsn,
+							  transactional,
+							  last_value,
+							  log_cnt,
+							  is_called);
+	OutputPluginWrite(ctx, true);
+}
+
 /*
  * Currently we always forward.
  */
@@ -1725,7 +1789,8 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 		entry->schema_sent = false;
 		entry->streamed_txns = NIL;
 		entry->pubactions.pubinsert = entry->pubactions.pubupdate =
-			entry->pubactions.pubdelete = entry->pubactions.pubtruncate = false;
+			entry->pubactions.pubdelete = entry->pubactions.pubtruncate =
+			entry->pubactions.pubsequence = false;
 		entry->new_slot = NULL;
 		entry->old_slot = NULL;
 		memset(entry->exprstate, 0, sizeof(entry->exprstate));
@@ -1739,13 +1804,13 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 	{
 		Oid			schemaId = get_rel_namespace(relid);
 		List	   *pubids = GetRelationPublications(relid);
-
+		char		objectType = pub_get_object_type_for_relkind(get_rel_relkind(relid));
 		/*
 		 * We don't acquire a lock on the namespace system table as we build
 		 * the cache entry using a historic snapshot and all the later changes
 		 * are absorbed while decoding WAL.
 		 */
-		List	   *schemaPubids = GetSchemaPublications(schemaId);
+		List	   *schemaPubids = GetSchemaPublications(schemaId, objectType);
 		ListCell   *lc;
 		Oid			publish_as_relid = relid;
 		int			publish_ancestor_level = 0;
@@ -1780,6 +1845,7 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 		entry->pubactions.pubupdate = false;
 		entry->pubactions.pubdelete = false;
 		entry->pubactions.pubtruncate = false;
+		entry->pubactions.pubsequence = false;
 
 		/*
 		 * Tuple slots cleanups. (Will be rebuilt later if needed).
@@ -1826,9 +1892,11 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 
 			/*
 			 * If this is a FOR ALL TABLES publication, pick the partition root
-			 * and set the ancestor level accordingly.
+			 * and set the ancestor level accordingly. If this is a FOR ALL
+			 * SEQUENCES publication, we publish it too but we don't need to
+			 * pick the partition root etc.
 			 */
-			if (pub->alltables)
+			if (pub->alltables || pub->allsequences)
 			{
 				publish = true;
 				if (pub->pubviaroot && am_partition)
@@ -1889,6 +1957,7 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 				entry->pubactions.pubupdate |= pub->pubactions.pubupdate;
 				entry->pubactions.pubdelete |= pub->pubactions.pubdelete;
 				entry->pubactions.pubtruncate |= pub->pubactions.pubtruncate;
+				entry->pubactions.pubsequence |= pub->pubactions.pubsequence;
 
 				/*
 				 * We want to publish the changes as the top-most ancestor