The telemetry alerting system identified a change in URLCLASSIFIER_LC_PREFIXES  and URLCLASSIFIER_PS_CONSTRUCT_TIME  on the 23rd of April. The size of the prefix cache and the time spent constructing it has shrunk. Is this expected?  http://alerts.telemetry.mozilla.org/index.html#/detectors/1/metrics/244/alerts/?from=2015-04-23&to=2015-04-23  http://alerts.telemetry.mozilla.org/index.html#/detectors/1/metrics/111/alerts/?from=2015-04-23&to=2015-04-23
Copying from email to francois: > It seems like it's when we create an in-memory lookup table with > some recent update data? It seems like it's counting the number of > hash prefixes that end up in these in-memory caches? Yes. Specifically, it measures the number of entries in the database, given that the number of prefixes we keep in RAM is equal to that. (Ok, strictly speaking: minus sub chunks) So this alert (and the associated graph) is telling us the size of the databases has dropped. This could be either: 1) Updates being broken, which is very bad. 2) The unwanted database starting to update and pulling down the average, which would be expected. > I also found a similar alert in March: > https://groups.google.com/forum/#!topic/mozilla.dev.telemetry-alerts/wqRRr4S3wko This was when the fragmentation problem occurred due to adding an extra list in Nightly, IIRC.
I think we would have noticed if updates had been broken in the last year so I assume this was due to the new lists.
Status: NEW → RESOLVED
Closed: 3 years ago
Resolution: --- → WONTFIX
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