Remove dead code and fix comments in fast-path function handling.

HandleFunctionRequest() is no longer responsible for reading the protocol
message from the client, since commit 2b3a8b20c2. Fix the outdated
comments.

HandleFunctionRequest() now always returns 0, because the code that used
to return EOF was moved in 2b3a8b20c2. Therefore, the caller no longer
needs to check the return value.

Reported by Andres Freund. Backpatch to all supported versions, even though
this doesn't have any user-visible effect, to make backporting future
patches in this area easier.

Discussion: https://www.postgresql.org/message-id/20170405010525[email protected]

diff --git a/src/backend/tcop/fastpath.c b/src/backend/tcop/fastpath.c
index ce3b9ebdca36152aa493a0e01a11ec5224f50805..5d4ba70e05cb7f8c9a8893bb0bc9b15aeae00bd3 100644 (file)
--- a/src/backend/tcop/fastpath.c
+++ b/src/backend/tcop/fastpath.c
@@ -249,24 +249,15 @@ fetch_fp_info(Oid func_id, struct fp_info * fip)
  * This corresponds to the libpq protocol symbol "F".
  *
  * INPUT:
- *     In protocol version 3, postgres.c has already read the message body
- *     and will pass it in msgBuf.
- *     In old protocol, the passed msgBuf is empty and we must read the
- *     message here.
- *
- * RETURNS:
- *     0 if successful completion, EOF if frontend connection lost.
- *
- * Note: All ordinary errors result in ereport(ERROR,...).  However,
- * if we lose the frontend connection there is no one to ereport to,
- * and no use in proceeding...
+ *     postgres.c has already read the message body and will pass it in
+ *     msgBuf.
  *
  * Note: palloc()s done here and in the called function do not need to be
  * cleaned up explicitly.  We are called from PostgresMain() in the
  * MessageContext memory context, which will be automatically reset when
  * control returns to PostgresMain.
  */
-int
+void
 HandleFunctionRequest(StringInfo msgBuf)
 {
    Oid         fid;
@@ -281,9 +272,8 @@ HandleFunctionRequest(StringInfo msgBuf)
    char        msec_str[32];
 
    /*
-    * Now that we've eaten the input message, check to see if we actually
-    * want to do the function call or not.  It's now safe to ereport(); we
-    * won't lose sync with the frontend.
+    * We only accept COMMIT/ABORT if we are in an aborted transaction, and
+    * COMMIT/ABORT cannot be executed through the fastpath interface.
     */
    if (IsAbortedTransactionBlockState())
        ereport(ERROR,
@@ -406,8 +396,6 @@ HandleFunctionRequest(StringInfo msgBuf)
                            msec_str, fip->fname, fid)));
            break;
    }
-
-   return 0;
 }
 
 /*

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 242ca4445df2a0ae024b27f2c446766a83324bf8..4721c6e3345eef70d62169b5808e924c13a601ae 100644 (file)
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -4140,19 +4140,7 @@ PostgresMain(int argc, char *argv[],
                /* switch back to message context */
                MemoryContextSwitchTo(MessageContext);
 
-               if (HandleFunctionRequest(&input_message) == EOF)
-               {
-                   /* lost frontend connection during F message input */
-
-                   /*
-                    * Reset whereToSendOutput to prevent ereport from
-                    * attempting to send any more messages to client.
-                    */
-                   if (whereToSendOutput == DestRemote)
-                       whereToSendOutput = DestNone;
-
-                   proc_exit(0);
-               }
+               HandleFunctionRequest(&input_message);
 
                /* commit the function-invocation transaction */
                finish_xact_command();

diff --git a/src/include/tcop/fastpath.h b/src/include/tcop/fastpath.h
index dc6905d48c7627b69df150b66e8e1b997c899814..fb5e08454262649864ac169f658f847bfcdec16f 100644 (file)
--- a/src/include/tcop/fastpath.h
+++ b/src/include/tcop/fastpath.h
@@ -16,6 +16,6 @@
 #include "lib/stringinfo.h"
 
 extern int GetOldFunctionMessage(StringInfo buf);
-extern int HandleFunctionRequest(StringInfo msgBuf);
+extern void HandleFunctionRequest(StringInfo msgBuf);
 
 #endif   /* FASTPATH_H */