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 Fix the outdated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.rt5azbya5fkbhvrx@alap3.anarazel.de

diff --git a/src/backend/tcop/fastpath.c b/src/backend/tcop/fastpath.c
index ab632d22b38dff1740f0c4d72f15eb36e40bf3e7..9c5eabccf14e3790da1eac6c2d868e7edaaf7c4a 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 7e6d17eaa9eedd98d64cac0f4bda886e7d6665d9..3ba3a0c6142b6601f639d2a3746bfe8ac12eb5fa 100644 (file)
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -4176,19 +4176,7 @@ 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 3f75121610e7512ede6d34fb42538fe3b96e0c3a..78621c5ff0eb67eebf8c184e248a86744cb2476f 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 */