2PC in pgoutput for shardman: append gid to avoid collisions.

arssher · arssher · commit 576d58906e7a · 2018-09-20T10:58:00.000+03:00
For all non-shardman xacts 2PC decoding is disabled. Also, add GUC enabling 2PC
decoding always in pgoutput to test it (011_twophase.pl).
diff --git a/src/backend/replication/logical/proto.c b/src/backend/replication/logical/proto.c
@@ -140,7 +140,7 @@ logicalrep_read_commit(StringInfo in, LogicalRepCommitData *commit_data,
  */
 void
 logicalrep_write_prepare(StringInfo out, ReorderBufferTXN *txn,
-						XLogRecPtr prepare_lsn)
+						 XLogRecPtr prepare_lsn, const char *gid)
 {
 	uint8		flags = 0;
 
@@ -165,7 +165,7 @@ logicalrep_write_prepare(StringInfo out, ReorderBufferTXN *txn,
 	pq_sendint64(out, txn->commit_time);
 
 	/* send gid */
-	pq_sendstring(out, txn->gid);
+	pq_sendstring(out, gid);
 }
 
 /*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
@@ -12,13 +12,18 @@
  */
 #include "postgres.h"
 
+#include "access/genam.h"
+#include "access/heapam.h"
 #include "catalog/pg_publication.h"
 
+#include "nodes/makefuncs.h"
+
 #include "replication/logical.h"
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
 
+#include "utils/guc.h"
 #include "utils/inval.h"
 #include "utils/int8.h"
 #include "utils/memutils.h"
@@ -27,6 +32,8 @@
 
 PG_MODULE_MAGIC;
 
+extern void _PG_init(void);
+
 extern void _PG_output_plugin_init(OutputPluginCallbacks *cb);
 
 static void pgoutput_startup(LogicalDecodingContext *ctx,
@@ -62,6 +69,7 @@ static bool publications_valid;
 static List *LoadPublications(List *pubnames);
 static void publication_invalidation_cb(Datum arg, int cacheid,
 							uint32 hashvalue);
+static char *append_shardman_node_id(const char *gid);
 
 /* Entry in the map used to remember which relation schemas we sent. */
 typedef struct RelationSyncEntry
@@ -75,12 +83,29 @@ typedef struct RelationSyncEntry
 /* Map used to remember which relation schemas we sent. */
 static HTAB *RelationSyncCache = NULL;
 
+/* GUC just for tests */
+static bool use_twophase;
+
 static void init_rel_sync_cache(MemoryContext decoding_context);
 static RelationSyncEntry *get_rel_sync_entry(PGOutputData *data, Oid relid);
 static void rel_sync_cache_relation_cb(Datum arg, Oid relid);
 static void rel_sync_cache_publication_cb(Datum arg, int cacheid,
 							  uint32 hashvalue);
 
+void
+_PG_init(void)
+{
+	DefineCustomBoolVariable(
+		"pgoutput.use_twophase",
+		"Toggle 2PC",
+		NULL,
+		&use_twophase,
+		false,
+		PGC_SUSET,
+		0,
+		NULL, NULL, NULL);
+}
+
 /*
  * Specify output plugin callbacks
  */
@@ -337,10 +362,17 @@ static void
 pgoutput_prepare_txn(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 					XLogRecPtr prepare_lsn)
 {
+	char *gid = txn->gid;
+
 	OutputPluginUpdateProgress(ctx);
 
 	OutputPluginPrepareWrite(ctx, true);
-	logicalrep_write_prepare(ctx->out, txn, prepare_lsn);
+	/* Append :sysid to gid to avoid collision */
+	if (strstr(gid, "pgfdw:") != NULL)
+		gid = psprintf("%s:%lx", txn->gid, GetSystemIdentifier());
+	logicalrep_write_prepare(ctx->out, txn, prepare_lsn, gid);
+	if (strstr(gid, "pgfdw:") != NULL)
+		pfree(gid);
 	OutputPluginWrite(ctx, true);
 }
 
@@ -351,23 +383,38 @@ static void
 pgoutput_commit_prepared_txn(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 					XLogRecPtr prepare_lsn)
 {
+	char *gid = txn->gid;
+
 	OutputPluginUpdateProgress(ctx);
 
 	OutputPluginPrepareWrite(ctx, true);
-	logicalrep_write_prepare(ctx->out, txn, prepare_lsn);
+	/* Append :sysid to gid to avoid collision */
+	if (strstr(gid, "pgfdw:") != NULL)
+		gid = psprintf("%s:%lx", txn->gid, GetSystemIdentifier());
+	logicalrep_write_prepare(ctx->out, txn, prepare_lsn, gid);
+	if (strstr(gid, "pgfdw:") != NULL)
+		pfree(gid);
 	OutputPluginWrite(ctx, true);
 }
+
 /*
  * PREPARE callback
  */
 static void
 pgoutput_abort_prepared_txn(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 					XLogRecPtr prepare_lsn)
 {
+	char *gid = txn->gid;
+
 	OutputPluginUpdateProgress(ctx);
 
 	OutputPluginPrepareWrite(ctx, true);
-	logicalrep_write_prepare(ctx->out, txn, prepare_lsn);
+	/* Append :sysid to gid to avoid collision */
+	if (strstr(gid, "pgfdw:") != NULL)
+		gid = psprintf("%s:%lx", txn->gid, GetSystemIdentifier());
+	logicalrep_write_prepare(ctx->out, txn, prepare_lsn, gid);
+	if (strstr(gid, "pgfdw:") != NULL)
+		pfree(gid);
 	OutputPluginWrite(ctx, true);
 }
 
@@ -502,13 +549,17 @@ pgoutput_truncate(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 /*
  * Filter out unnecessary two-phase transactions.
  *
- * Currently, we forward all two-phase transactions
+ * Make 2PC on shardman's xacts.
  */
 static bool
 pgoutput_filter_prepare(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
-								TransactionId xid, const char *gid)
+						TransactionId xid, const char *gid)
 {
-	return false;
+	if (strstr(gid, "pgfdw:") != NULL) /* shardman */
+	{
+		return false;
+	}
+	return !use_twophase;
 }
 
 /*
diff --git a/src/include/replication/logicalproto.h b/src/include/replication/logicalproto.h
@@ -92,7 +92,7 @@ extern void logicalrep_write_commit(StringInfo out, ReorderBufferTXN *txn,
 extern void logicalrep_write_abort(StringInfo out, ReorderBufferTXN *txn,
 						XLogRecPtr abort_lsn);
 extern void logicalrep_write_prepare(StringInfo out, ReorderBufferTXN *txn,
-						XLogRecPtr prepare_lsn);
+									 XLogRecPtr prepare_lsn, const char *gid);
 extern void logicalrep_read_commit(StringInfo in,
 					   LogicalRepCommitData *commit_data, uint8 *flags);
 extern void logicalrep_read_prepare(StringInfo in,
diff --git a/src/test/subscription/t/011_twophase.pl b/src/test/subscription/t/011_twophase.pl
@@ -11,6 +11,7 @@
 $node_publisher->append_conf(
         'postgresql.conf', qq(
         max_prepared_transactions = 10
+	    pgoutput.use_twophase = true
         ));
 $node_publisher->start;
 

Original file line number	Diff line number	Diff line change
`@@ -140,7 +140,7 @@ logicalrep_read_commit(StringInfo in, LogicalRepCommitData *commit_data,`
`140`	`140`	`*/`
`141`	`141`	`void`
`142`	`142`	`logicalrep_write_prepare(StringInfo out, ReorderBufferTXN *txn,`
`143`		`- XLogRecPtr prepare_lsn)`
	`143`	`+ XLogRecPtr prepare_lsn, const char *gid)`
`144`	`144`	`{`
`145`	`145`	`uint8 flags = 0;`
`146`	`146`
`@@ -165,7 +165,7 @@ logicalrep_write_prepare(StringInfo out, ReorderBufferTXN *txn,`
`165`	`165`	`pq_sendint64(out, txn->commit_time);`
`166`	`166`
`167`	`167`	`/* send gid */`
`168`		`- pq_sendstring(out, txn->gid);`
	`168`	`+ pq_sendstring(out, gid);`
`169`	`169`	`}`
`170`	`170`
`171`	`171`	`/*`