bdr: Add bdr.do_not_replicate GUC

Suppresses replication of changes from a session by setting the
origin replication identifier to DoNotReplicateRepNodeId.

diff --git a/bdr.c b/bdr.c
index 8dddd631769c00e5a86d4c5e717a37b0526cfa95..d9cb98a53d4f2ef4a5bb86b7e4f4dbfa274d21ae 100644 (file)
--- a/bdr.c
+++ b/bdr.c
@@ -90,6 +90,7 @@ int bdr_default_apply_delay;
 int bdr_max_workers;
 static bool bdr_skip_ddl_replication;
 bool bdr_skip_ddl_locking;
+bool bdr_do_not_replicate;
 
 /* shmem init hook to chain to on startup, if any */
 static shmem_startup_hook_type prev_shmem_startup_hook = NULL;
@@ -1120,6 +1121,43 @@ bdr_is_bdr_activated_db(void)
    return false;
 }
 
+static bool
+bdr_do_not_replicate_check_hook(bool *newvalue, void **extra, GucSource source)
+{
+   if (!(*newvalue))
+       /* False is always acceptable */
+       return true;
+
+   /*
+    * Only set bdr.do_not_replicate if configured via startup packet from the
+    * client application. This prevents possibly unsafe accesses to the
+    * replication identifier state in postmaster context, etc.
+    */
+   if (source != PGC_S_CLIENT)
+       return false;
+
+   Assert(IsUnderPostmaster);
+   Assert(!IsBackgroundWorker);
+
+   return true;
+}
+
+/*
+ * Override the origin replication identifier that this session will record for
+ * its transactions. We need this mainly when applying dumps during
+ * init_replica.
+ */
+static void
+bdr_do_not_replicate_assign_hook(bool newvalue, void *extra)
+{
+   if (newvalue)
+   {
+       /* Mark these transactions as not to be replicated to other nodes */
+       SetupCachedReplicationIdentifier(DoNotReplicateRepNodeId);
+   }
+}
+
+
 /*
  * Entrypoint of this module - called at shared_preload_libraries time in the
  * context of the postmaster.
@@ -1283,6 +1321,18 @@ _PG_init(void)
                             PGC_BACKEND,
                             0,
                             NULL, NULL, NULL);
+
+   DefineCustomBoolVariable("bdr.do_not_replicate",
+                            "Internal. Set during local initialization from basebackup only",
+                            NULL,
+                            &bdr_do_not_replicate,
+                            false,
+                            PGC_BACKEND,
+                            0,
+                            bdr_do_not_replicate_check_hook,
+                            bdr_do_not_replicate_assign_hook,
+                            NULL);
+
    bdr_label_init();
 
    /* if nothing is configured, we're done */

diff --git a/bdr_replication_identifier.h b/bdr_replication_identifier.h
index 488eeac7545e8d9aee9e2618d22e7856c0ffe369..31e4969a4cd4c5e06c6cace788287389a6e8f331 100644 (file)
--- a/bdr_replication_identifier.h
+++ b/bdr_replication_identifier.h
@@ -23,6 +23,7 @@
 
 typedef uint16 RepNodeId;
 #define InvalidRepNodeId 0
+#define DoNotReplicateRepNodeId USHRT_MAX
 
 extern PGDLLIMPORT RepNodeId replication_origin_id;
 extern PGDLLIMPORT TimestampTz replication_origin_timestamp;