Redis Configuration Optimization

  • Resolved decentris

    (@decentris)


    5 years, 11 months ago

    Dear Till,

    another small issue, which you might certainly help me with.

    Since activating the Redis Cache I recognize some fluctuations in backend performance. Sometimes is it really fast (faster than before) but sometimes it gets stuck (which was not the case before activating Redis).

    Especially the “Update” and “Installed Plugin” – Section of the backend often prouduce a white screen. Also the case when installing a new plugin. After refreshing the site multiple times, it shows the plugins list again and fast just to get slow next time. When I turn of Redis, it’s slow but doesn’t hang. (I must say that I have got a lot of plugins installed, so it might be no wonder, that it is slow but it did never hang before)

    So I wonder if I might have got the wrong redis.conf parameters (especially maxmemory and maxmemory-policy)

    Have you got some hint for me, what this could be and how to solve it?

    Thank you very much in advance.

    Best,
    Johannes

Viewing 8 replies - 1 through 8 (of 8 total)
  • Plugin Author Till Krüss

    (@tillkruess)

    5 years, 11 months ago

    Hi Johannes,

    that sounds like HTTP requests slowing down your site. The easiest way to find out what’s causing that is using Query Monitor (the plugin), or using New Relic.

    Let me know what you find.

    Thread Starter decentris

    (@decentris)

    5 years, 11 months ago

    Hi Till,

    I am searching but it’s like a needle in the haystack. Just for correct understanding (I haven’t used the opcache and redis so far):

    Query Monitor tells me:

    Objekt-Cache
    93,8% Trefferquote (18.312 Treffer, 1.220 Fehler)
    Externer Objekt-Cache verwendet
    Opcode cache in use: APC
    Opcode cache in use: Zend OPcache

    Does that sound good?

    I also set “maxmemory 1024MB” and “maxmemory-policy allkeys-lru” (that’s the only thing I changed in the redis.conf – file.

    Please tell me, if this is the right setting.

    Regarding the Query Monitor analysis:
    There are a lot of plugins generating requests but I think I found one big culprit: the shortcode-ultimate-extra plugin generates curl- and 400BadRequest errors when requesting PluginUpdateChecker_2_0->requestInfo() from https://kernl.us/api/v1/updates/. I already wrote the support. Let’s see, what they can do.

    I’ll keep you informed. Just be so kind and answer my above questions about redis opcache config.

    Thanks a lot, Till

    Best,
    Johannes

    Plugin Author Till Krüss

    (@tillkruess)

    5 years, 11 months ago

    Die maxmemory-policy allkeys-lru ist super 👍🏻

    18.312 Treffer, that’s a lot of hits, no wonder why it’s slow. You might want to switch to the more efficient Pro version.

    If you’re having real trouble with that site, I’d use New Relic or Blackfire to find the culprit that slowing down your site.

    Thread Starter decentris

    (@decentris)

    5 years, 11 months ago

    Ok, I’ll have a look. At the moment I’ve got 121 plugins active (yeah, I know, but I need them all somehow..) There is plenty of room for optimization.

    Wie ist die maxmemory 1024MB? Is that too much maxmem, or is it too less or is it just right?

    This would be the last question.

    I, of course, keep you updated on my findings. The Pro-Version of your plugin looks very good. I will think about it, promised. But first I want to see, what the fixing of this shortcode-ultimate – stuff brings.

    Best,
    Johannes

    PS: Auch ein Nachtarbeiter, hmm? 🙂

    Plugin Author Till Krüss

    (@tillkruess)

    5 years, 11 months ago

    The memory of Redis depends on your usage. Some sites need 32MB some need 12GB.

    Thread Starter decentris

    (@decentris)

    5 years, 11 months ago

    Should I choose “unlimited” (maxmemory 0), to be on the safe side?

    Thread Starter decentris

    (@decentris)

    5 years, 11 months ago

    PS: I just had to do a database backup. After importing, there was some mismatch of the data (some data of the last view hours were like before import and the older ones like the time of the backup, which should be that way).

    I cleared the Redis-cache and the reimported backup again and suddenly it worked out.

    Is the cache the culprit of this strange behaviour and if yes, do I always have to clear the cache before importing a db-backup?

    Thanks a lot in advance,
    Johannes

    Plugin Author Till Krüss

    (@tillkruess)

    5 years, 11 months ago

    Should I choose “unlimited” (maxmemory 0), to be on the safe side?

    That depends on your server specs and setup.

Viewing 8 replies - 1 through 8 (of 8 total)

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