Fix libpq compression if no algorithms are available

Author: knizhnik

src/interfaces/libpq/fe-connect.c

@@ -431,10 +431,12 @@ pgthreadlock_t pg_g_threadlock = default_threadlock;
 void
 pqDropConnection(PGconn *conn, bool flushInput)
 {
-	/* Release compression streams */
-	zpq_free(conn->zstream);
-	conn->zstream = NULL;
-
+	if (conn->zstream)
+	{
+		/* Release compression streams */
+		zpq_free(conn->zstream);
+		conn->zstream = NULL;
+	}
 	/* Drop any SSL state */
 	pqsecure_close(conn);
 

src/interfaces/libpq/fe-misc.c

@@ -898,7 +898,7 @@ pqSendSome(PGconn *conn, int len)
 	}
 
 	/* while there's still data to send */
-	while (len > 0 || zpq_buffered(conn->zstream))
+	while (len > 0 || (conn->zstream && zpq_buffered(conn->zstream)))
 	{
 		int			sent;
 		size_t      processed = 0;
@@ -964,7 +964,7 @@ pqSendSome(PGconn *conn, int len)
 			remaining -= sent;
 		}
 
-		if (len > 0 || sent < 0 || zpq_buffered(conn->zstream))
+		if (len > 0 || sent < 0 || (conn->zstream && zpq_buffered(conn->zstream)))
 		{
 			/*
 			 * We didn't send it all, wait till we can send more.