Relay Cache efficiency ?

[dgillier]

Hello,

I'm using the last version of Relay with Redis 6.0.16 and 3000+ keys in a Laravel app…

I'd tried the Relay::stats() and I got this type of results:

   [usage] => Array
        (
            [total_requests] => 13789
            [active_requests] => 1
            [max_active_requests] => 4
            [free_epoch_records] => 127
        )
    [stats] => Array
        (
            [requests] => 44830
            [misses] => 41522
            [hits] => 3236
            [errors] => 0
            [dirty_skips] => 0
            [empty] => 0
            [oom] => 0
            [ops_per_sec] => 1
            [bytes_sent] => 28254805
            [bytes_received] => 47861476
            [command_usec] => 0
            [rinit_usec] => 599528
            [rshutdown_usec] => 421961
            [sigio_usec] => 6244
        )
            [memory] => Array
        (
            [total] => 33554432
            [limit] => 33554432
            [active] => 7225568
            [used] => 5460640
        )

It looks the cache is not very efficient (less than 10% hits).
Is it related to cache memory size, am I missing something or is it normal ?

Thanks :)
Denis
P.S: I'm concerned by cache efficiency as in production the Redis Instance will be on another hosting region and I was expecting the cache to mitigate the latency problem…

[michael-grunder]

It would be interesting to see the full redis info output as well, or at least the parts that provide information about the keyspace (total keys, total used memory, etc).

How efficient Relay's cache is is just going to depend on what specific Redis operations are being performed. If it's a write-heavy workload then the hit rate would be low for example.

[dgillier]

Thanks for answering :)
(Redis is really used as a cache for fews hours by the Laravel App, so mostly reads)

Here it is…

                    [redis] => Array
                        (
                            [redis_version] => 6.0.16
                            [used_memory] => 19577136
                            [used_memory_peak] => 27835712
                            [total_system_memory] => 2014752768
                            [tracking_total_keys] => 3434
                            [maxmemory] => 0
                            [maxmemory_policy] => noeviction
                            [updated] => 1712856092926185
                        )

[michael-grunder]

If it's mostly reads then I would expect a much higher hit rate. What does info commandstats show? I'm curious about what kinds of keys are being cached and what operations are being performed on them.

[dgillier]

Mostly Laravel Sessions and Queue (R/W of course) and caches (templates, config values and mysql data).
Here is the redis-cli commadstats:

# Commandstats
cmdstat_set:calls=22827,usec=163375,usec_per_call=7.16
cmdstat_hget:calls=1685679,usec=4169625,usec_per_call=2.47
cmdstat_expire:calls=15594207,usec=24173385,usec_per_call=1.55
cmdstat_eval:calls=8269724,usec=306636072,usec_per_call=37.08
cmdstat_hsetnx:calls=153032,usec=5187075,usec_per_call=33.90
cmdstat_zremrangebyscore:calls=16118978,usec=84607987,usec_per_call=5.25
cmdstat_setex:calls=5327958,usec=70116291,usec_per_call=13.16
cmdstat_flushdb:calls=219,usec=260001,usec_per_call=1187.22
cmdstat_rpush:calls=155269,usec=6313380,usec_per_call=40.66
cmdstat_zremrangebyrank:calls=827018,usec=7109878,usec_per_call=8.60
cmdstat_llen:calls=11255024,usec=38901344,usec_per_call=3.46
cmdstat_client:calls=140334,usec=399101,usec_per_call=2.84
cmdstat_setnx:calls=7761165,usec=27168254,usec_per_call=3.50
cmdstat_select:calls=5702136,usec=9406739,usec_per_call=1.65
cmdstat_info:calls=225547,usec=14829403,usec_per_call=65.75
cmdstat_exec:calls=826809,usec=9910032,usec_per_call=11.99
cmdstat_del:calls=1025950,usec=9521245,usec_per_call=9.28
cmdstat_exists:calls=28605,usec=877666,usec_per_call=30.68
cmdstat_sadd:calls=156176,usec=6068803,usec_per_call=38.86
cmdstat_zrem:calls=156640,usec=1539243,usec_per_call=9.83
cmdstat_zrevrangebyscore:calls=153540,usec=2142937,usec_per_call=13.96
cmdstat_hello:calls=46778,usec=407352,usec_per_call=8.71
cmdstat_incrby:calls=2324,usec=10618,usec_per_call=4.57
cmdstat_lrange:calls=297,usec=1839,usec_per_call=6.19
cmdstat_zrange:calls=9753,usec=42796,usec_per_call=4.39
cmdstat_multi:calls=826809,usec=554371,usec_per_call=0.67
cmdstat_expireat:calls=154849,usec=246062,usec_per_call=1.59
cmdstat_incr:calls=503,usec=3405,usec_per_call=6.77
cmdstat_hmget:calls=1180845,usec=11764370,usec_per_call=9.96
cmdstat_zcount:calls=9753,usec=138526,usec_per_call=14.20
cmdstat_hmset:calls=15861386,usec=195409599,usec_per_call=12.32
cmdstat_command:calls=1,usec=725,usec_per_call=725.00
cmdstat_lpop:calls=2747339,usec=47224127,usec_per_call=17.19
cmdstat_zrangebyscore:calls=5340544,usec=161044045,usec_per_call=30.15
cmdstat_zadd:calls=16633287,usec=197934446,usec_per_call=11.90
cmdstat_smembers:calls=156636,usec=1727942,usec_per_call=11.03
cmdstat_get:calls=8312371,usec=88461885,usec_per_call=10.64
cmdstat_ltrim:calls=297,usec=2028,usec_per_call=6.83

[dgillier]

And stats:

# Stats
total_connections_received:4384661
total_commands_processed:126875370
instantaneous_ops_per_sec:25
total_net_input_bytes:32382626992
total_net_output_bytes:66307149618
instantaneous_input_kbps:5.79
instantaneous_output_kbps:3.55
rejected_connections:0
sync_full:0
sync_partial_ok:0
sync_partial_err:0
expired_keys:428731
expired_stale_perc:0.01
expired_time_cap_reached_count:0
expire_cycle_cpu_milliseconds:428219
evicted_keys:0
keyspace_hits:8441992
keyspace_misses:19691483
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:1060
migrate_cached_sockets:0
slave_expires_tracked_keys:0
active_defrag_hits:0
active_defrag_misses:0
active_defrag_key_hits:0
active_defrag_key_misses:0
tracking_total_keys:4035
tracking_total_items:98662
tracking_total_prefixes:0
unexpected_error_replies:0
total_reads_processed:90383982
total_writes_processed:85876576
io_threaded_reads_processed:0
io_threaded_writes_processed: