Performance Issues

  • LWD

    (@kieranbarnes)


    1 year, 3 months ago

    We’ve got an interesting performance issue with one customer’s store.

    With Redis enabled, it adds around 20 seconds per page load. This is confirmed in New Relic. Disabling the object cache, page time reduces.

    The Redis database is only 20Mb-ish when warm. The site is quite large, 100,000 users, 7,000 products, 159,000 orders. (8,800,000 rows in postmeta)

    We have another similar site on the same server (different Redis DB) and that’s perfect.

    I can’t spot anything obvious that would cause Redis to behave poorly on this site only.

    Any suggestions?

Viewing 6 replies - 1 through 6 (of 6 total)
  • Thread Starter LWD

    (@kieranbarnes)

    New Relic screenshot (Orange is the Redis time, blue is the PHP time)

    Plugin Author Till Krüss

    (@tillkruess)

    Can you post the breakdown of Redis commands per page load from New Relic? I’d like to see which commands are called, how often and how long they take.

    Thread Starter LWD

    (@kieranbarnes)

    Is this any use Till?

    Plugin Author Till Krüss

    (@tillkruess)

    It somewhat is. 93% of your Redis operations are writes, which is bad. Typically you’d see less than 1% of the page load being writes to Redis.

    You gotta trace what keys are being written, I think New Relic will show you that too. Feel free to post more screenshots after drilling down.

    Thread Starter LWD

    (@kieranbarnes)

    Apologises for the delay here, just coming back round to this issue. With Redis disabled on this site, I don’t see many MySQL writes

    /* LWD CUSTOM REDIS */
define( 'WP_REDIS_HOST', '127.0.0.1' );
define( 'WP_REDIS_PORT', 6379 );
define( 'WP_REDIS_DATABASE', 1 );
define( 'WP_REDIS_TIMEOUT', 1 );
define( 'WP_REDIS_READ_TIMEOUT', 1 );
define( 'WP_REDIS_DISABLE_BANNERS', true );
define( 'WP_REDIS_PREFIX', 'zzz_');

    The client has an almost identical site that works perfectly.

    I don’t see what would cause so many writes when the plugin is enabled.

    Anything that could be wrong in the redis.conf?

    PS: The client would be happy to pay for your time assisting on this. Let me know if you’re able to do this

    Plugin Support Julie

    (@julieadrienne)

    Hey Kieran! When you say almost identical site, can you list the plugins that are present on the worse performing site, that aren’t active on the well performing one?

Viewing 6 replies - 1 through 6 (of 6 total)
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