Reinstate "Microoptimise ckdbq_process"

This reverts commit f35f54a642.

src/stratifier.c

@@ -6779,7 +6779,7 @@ static bool test_and_clear(bool *val, mutex_t *lock)
 static void ckdbq_process(ckpool_t *ckp, char *msg)
 {
 	sdata_t *sdata = ckp->sdata;
-	size_t responselen = 0;
+	size_t responselen;
 	char *buf = NULL;
 
 	while (!buf) {
@@ -6799,16 +6799,15 @@ static void ckdbq_process(ckpool_t *ckp, char *msg)
 
 	/* Process any requests from ckdb that are heartbeat responses with
 	 * specific requests. */
-	if (likely(buf))
 	responselen = strlen(buf);
-	if (likely(responselen > 0)) {
+	if (likely(responselen > 1)) {
 		char *response = alloca(responselen);
 		int offset = 0;
 
 		memset(response, 0, responselen);
-		if (sscanf(buf, "%*d.%*d.%c%n", response, &offset) > 0) {
-			strcpy(response+1, buf+offset);
-			if (safecmp(response, "ok")) {
+		if (likely(sscanf(buf, "%*d.%*d.%c%n", response, &offset) > 0)) {
+			strcpy(response + 1, buf + offset);
+			if (likely(safecmp(response, "ok"))) {
 				char *cmd;
 
 				cmd = response;
@@ -6822,8 +6821,8 @@ static void ckdbq_process(ckpool_t *ckp, char *msg)
 				LOGWARNING("Got ckdb failure response: %s", buf);
 		} else
 			LOGWARNING("Got bad ckdb response: %s", buf);
-		free(buf);
 	}
+	free(buf);
 }
 
 static int transactions_by_jobid(sdata_t *sdata, const int64_t id)