I wrote:
> Alexander Lakhin <exclus...@gmail.com> writes:
>> What bothers me is:
>> There must be a call to *WSACleanup* for each successful call to
>> WSAStartup
>>
>> <https://docs.microsoft.com/en-us/windows/desktop/api/winsock/nf-winsock-wsastartup>.
> Yeah, that is a very odd statement. Surely, the Windows kernel manages
> to cope if a program crashes without having done that. So what exactly
> is the downside of intentionally not doing it?
A bit of grepping showed me that the backend, initdb, and pg_regress
all call WSAStartup without ever doing WSACleanup, and we've seen no
ill effects from that. So it seems clear that this documentation can
safely be ignored.
I propose the attached patch. If this doesn't cause buildfarm problems,
perhaps we should back-patch it.
BTW, I notice that libpq is asking WSAStartup for Winsock version 1.1,
which is remarkably ancient. Almost everyplace else is asking for
version 2.2, which has been current for a decade or two. Shouldn't
we update that? (It occurs to me to wonder if this in itself is
some kind of problem; I wonder how well Winsock works when there are
requests for different API versions in the same program.)
regards, tom lane
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 3315f1dd05..de60281fcb 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -91,21 +91,6 @@
</para>
</warning>
- <note>
- <para>
- On Windows, there is a way to improve performance if a single
- database connection is repeatedly started and shutdown. Internally,
- libpq calls <function>WSAStartup()</function> and <function>WSACleanup()</function> for connection startup
- and shutdown, respectively. <function>WSAStartup()</function> increments an internal
- Windows library reference count which is decremented by <function>WSACleanup()</function>.
- When the reference count is just one, calling <function>WSACleanup()</function> frees
- all resources and all DLLs are unloaded. This is an expensive
- operation. To avoid this, an application can manually call
- <function>WSAStartup()</function> so resources will not be freed when the last database
- connection is closed.
- </para>
- </note>
-
<variablelist>
<varlistentry id="libpq-PQconnectdbParams">
<term><function>PQconnectdbParams</function><indexterm><primary>PQconnectdbParams</primary></indexterm></term>
diff --git a/src/bin/pg_dump/parallel.c b/src/bin/pg_dump/parallel.c
index a967e11378..b51cc76c7d 100644
--- a/src/bin/pg_dump/parallel.c
+++ b/src/bin/pg_dump/parallel.c
@@ -229,19 +229,6 @@ static char *readMessageFromPipe(int fd);
(strncmp(msg, prefix, strlen(prefix)) == 0)
-/*
- * Shutdown callback to clean up socket access
- */
-#ifdef WIN32
-static void
-shutdown_parallel_dump_utils(int code, void *unused)
-{
- /* Call the cleanup function only from the main thread */
- if (mainThreadId == GetCurrentThreadId())
- WSACleanup();
-}
-#endif
-
/*
* Initialize parallel dump support --- should be called early in process
* startup. (Currently, this is called whether or not we intend parallel
@@ -267,8 +254,7 @@ init_parallel_dump_utils(void)
pg_log_error("WSAStartup failed: %d", err);
exit_nicely(1);
}
- /* ... and arrange to shut it down at exit */
- on_exit_nicely(shutdown_parallel_dump_utils, NULL);
+
parallel_init_done = true;
}
#endif
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index af27fee6b5..704c9e2f79 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -3871,23 +3871,30 @@ makeEmptyPGconn(void)
#ifdef WIN32
/*
- * Make sure socket support is up and running.
+ * Make sure socket support is up and running in this process.
+ *
+ * Note: the Windows documentation says that we should eventually do a
+ * matching WSACleanup() call, but experience suggests that that is at
+ * least as likely to cause problems as fix them. So we don't.
*/
- WSADATA wsaData;
+ static bool wsastartup_done = false;
- if (WSAStartup(MAKEWORD(1, 1), &wsaData))
- return NULL;
+ if (!wsastartup_done)
+ {
+ WSADATA wsaData;
+
+ if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0)
+ return NULL;
+ wsastartup_done = true;
+ }
+
+ /* Forget any earlier error */
WSASetLastError(0);
-#endif
+#endif /* WIN32 */
conn = (PGconn *) malloc(sizeof(PGconn));
if (conn == NULL)
- {
-#ifdef WIN32
- WSACleanup();
-#endif
return conn;
- }
/* Zero all pointers and booleans */
MemSet(conn, 0, sizeof(PGconn));
@@ -4080,10 +4087,6 @@ freePGconn(PGconn *conn)
termPQExpBuffer(&conn->workBuffer);
free(conn);
-
-#ifdef WIN32
- WSACleanup();
-#endif
}
/*
