From dea064712b278a7cd14323f96745f9b06bbca6eb Mon Sep 17 00:00:00 2001
From: John Sully <john@csquare.ca>
Date: Tue, 16 Feb 2021 21:07:43 +0000
Subject: [PATCH] Disable async rehash with single threads, it causes slowdowns
 as the rehash never completes

Former-commit-id: 5d08dbdf76c0fd1e0cfcf86b97ef3e656f0e4f5d
---
 src/server.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/server.cpp b/src/server.cpp
index eda89bc0e..a006d4da0 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -1950,7 +1950,7 @@ void databasesCron(bool fMainThread) {
                 ::dict *dict = g_pserver->db[rehash_db]->dictUnsafeKeyOnly();
                 /* Are we async rehashing? And if so is it time to re-calibrate? */
                 /* The recalibration limit is a prime number to ensure balancing across threads */
-                if (rehashes_per_ms > 0 && async_rehashes < 131 && !cserver.active_defrag_enabled) {
+                if (rehashes_per_ms > 0 && async_rehashes < 131 && !cserver.active_defrag_enabled && cserver.cthreads > 1) {
                     serverTL->rehashCtl = dictRehashAsyncStart(dict, rehashes_per_ms);
                     ++async_rehashes;
                 }