API for error codes?

[JRaspass]

Migrated from rt.cpan.org #81674 (status was 'open')

Requestors:

• clh@pobox.com

From clh@pobox.com on 2012-12-04 00:05:57
:

Have I overlooked the API for retrieving a detailed diagnostic message
or code when an action such as set() returns false?

Thanks
Chap

[JRaspass]

From finn_hakansson@yahoo.com on 2012-12-05 14:57:44
:

The API doesn't offer such feedback. If get() returns
undef, you can't know if it was a plain cache miss or
an error. At least for set(), an undef means there was
an error of some sort.

It would be excellent if there was a way to know if the
memcached client encountered an error with a memcached
instance (and which memcached instance it was).

On Mon Dec 03 19:05:57 2012, clh@pobox.com wrote:

Have I overlooked the API for retrieving a detailed diagnostic message
or code when an action such as set() returns false?

Thanks
Chap

[JRaspass]

From kroki@cpan.org on 2012-12-05 15:21:49
:

On Mon Dec 03 19:05:57 2012, clh@pobox.com wrote:

Have I overlooked the API for retrieving a detailed diagnostic message
or code when an action such as set() returns false?

As docs say set() returns false when server rejects the command, and
IIRC the only reason for that is that the item is larger then ~1MB
limit. You may set max_size parameter to a somewhat lower value to
reject big items right on the client.

For network errors set() returns undef.

[JRaspass]

From kroki@cpan.org on 2012-12-05 15:31:32
:

On Wed Dec 05 09:57:44 2012, finn_hakansson@yahoo.com wrote:

It would be excellent if there was a way to know if the
memcached client encountered an error with a memcached
instance (and which memcached instance it was).

While it's technically possible to add some call to retrieve exact
reason of the last error, I have certain doubts that it'll worth it.
C::M::F is an interface to a cache. When something wasn't retrieved
from the cache for whatever reason one has to obtain the data by other
means. Knowing the exact cause won't help much as there won't be
anything one could do about that. IMHO any monitoring of memcached
instances shouldn't be mixed with cache access from the application.
For separate monitoring, periodically setting and getting a particular
value from each memcached instance may be enough.
https://github.com/tsee/p5-Cache-Memcached-Fast adds some server stats
that may also be used for tuning.