From 4ab9f08ce049d46c76fd34da965e36bf9d3160e1 Mon Sep 17 00:00:00 2001
From: sam marshall <s.marshall@open.ac.uk>
Date: Wed, 31 Aug 2022 11:40:34 +0100
Subject: [PATCH] MDL-75369 Redis: Remove unnecessary ping after connect

The Redis cache store and session handler both do a 'ping()' after
connecting to Redis. This is unnecessary because the connect() call
has just checked the network connection and it's hardly likely that
the server has gone down since then.

According to my profiling, both connect() and ping() take
measurable time when talking to a separate server, i.e. a few
milliseconds. So it's not the case that connect() doesn't really
talk to the server, as I initially wondered.

If using Redis on a separate (non-localhost) server for both session
and cache store, removing these ping calls can save a millisecond
or two per request.
---
 cache/stores/redis/lib.php    | 3 +--
 lib/classes/session/redis.php | 1 -
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/cache/stores/redis/lib.php b/cache/stores/redis/lib.php
index 800bff13ac8..8521812ee72 100644
--- a/cache/stores/redis/lib.php
+++ b/cache/stores/redis/lib.php
@@ -216,8 +216,7 @@ class cachestore_redis extends cache_store implements cache_is_key_aware, cache_
                 if (!empty($prefix)) {
                     $redis->setOption(Redis::OPT_PREFIX, $prefix);
                 }
-                // Database setting option...
-                $this->isready = $this->ping($redis);
+                $this->isready = true;
             } else {
                 $this->isready = false;
             }
diff --git a/lib/classes/session/redis.php b/lib/classes/session/redis.php
index 605df12c2de..c7e6d407772 100644
--- a/lib/classes/session/redis.php
+++ b/lib/classes/session/redis.php
@@ -227,7 +227,6 @@ class redis extends handler {
                         throw new RedisException('Unable to select Redis database '.$this->database.'.');
                     }
                 }
-                $this->connection->ping();
                 return true;
             } catch (RedisException $e) {
                 $logstring = "Failed to connect (try {$counter} out of {$maxnumberofretries}) to redis ";