Prevent log_replication_commands from causing SQL commands to be logged.

Commit 7c4f524 allowed walsender to execute normal SQL commands
to support table sync feature in logical replication. Previously
while log_statement caused such SQL commands to be logged,
log_replication_commands caused them to be logged, too.
That is, such SQL commands were logged twice unexpectedly
when those settings were both enabled.

This commit forces log_replication_commands to log only replication
commands, to prevent normal SQL commands from being logged twice.

Author: Masahiko Sawada
Reviewed-by: Kyotaro Horiguchi
Reported-by: Fujii Masao
Discussion: http://postgr.es/m/CAHGQGwFDWh_Qr-q_GEMpD+qH=vYPMdVqw=ZOSY3kX_Pna9R9SA@mail.gmail.com

diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index dbb10c7b00665c520cf5ab3be278e59883e3bc9e..26090738fc347e701cbc71a5313c254d2495d5fe 100644 (file)
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1368,14 +1368,6 @@ exec_replication_command(const char *cmd_string)
    MemoryContext cmd_context;
    MemoryContext old_context;
 
-   /*
-    * Log replication command if log_replication_commands is enabled. Even
-    * when it's disabled, log the command with DEBUG1 level for backward
-    * compatibility.
-    */
-   ereport(log_replication_commands ? LOG : DEBUG1,
-           (errmsg("received replication command: %s", cmd_string)));
-
    /*
     * CREATE_REPLICATION_SLOT ... LOGICAL exports a snapshot until the next
     * command arrives. Clean up the old stuff if there's anything.
@@ -1399,6 +1391,16 @@ exec_replication_command(const char *cmd_string)
 
    cmd_node = replication_parse_result;
 
+   /*
+    * Log replication command if log_replication_commands is enabled. Even
+    * when it's disabled, log the command with DEBUG1 level for backward
+    * compatibility. Note that SQL commands are not logged here, and will be
+    * logged later if log_statement is enabled.
+    */
+   if (cmd_node->type != T_SQLCmd)
+       ereport(log_replication_commands ? LOG : DEBUG1,
+               (errmsg("received replication command: %s", cmd_string)));
+
    /*
     * CREATE_REPLICATION_SLOT ... LOGICAL exports a snapshot. If it was
     * called outside of transaction the snapshot should be cleared here.