Troubleshoot

Troubleshoot#

This guide shows you how to find the cause of the most common problems. Start with the status endpoint, as Monitor the cache describes.

Plone does not start#

The traceback ends with a ValueError naming a REDIS_MEMOIZE_* variable. Fix that variable; Configuration lists the values each one accepts.

active is false#

REDIS_MEMOIZE_URL is not in the environment of the Plone process. Check the environment of the container or service, not of your shell.

The status endpoint answers 404#

The package's ZCML is not loaded. If your site disables autoinclude, include it as Install the package describes.

Nothing reaches Redis#

Check, in this order:

  1. breaker.open is true: the instance cannot reach Redis. Read server.error, and the WARNING in the instance's log.

  2. The function's route is ram-excluded: an include or exclude pattern keeps it in RAM. Its reason names the pattern.

  3. The function's route is ram-not-shareable: its values are not plain data. Its reason names the part of the value at fault.

  4. The function is not listed at all: it was not called in this process since the start, or it is not cached through plone.memoize.

A function stays in RAM, and it should not#

The route ram-not-shareable lasts until the process restarts. The log has an INFO line with the reason, such as value['portlet'] is a my.addon.Portlet. Change the function to return plain data, as What "shareable" means describes, and restart.

undecodable grows#

Instances that run different code share one prefix, and one stores values the other cannot read. This is expected during a rolling deploy, and stops when every instance runs the new code. If it does not stop, give each version its own REDIS_MEMOIZE_PREFIX.

Instances show different values#

Some value in the cache depends on something its key leaves out, such as a setting that differs between instances. Exclude that function, as Include and exclude functions describes, and read When not to use it.

Old values survive a deploy#

They live in Redis until their TTL runs out. Invalidate them, as Invalidate cached values after a deploy describes.

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