Persistence extensions: fix potential infinite loop #5018
Conversation
Signed-off-by: Mark Herwege <[email protected]>
Signed-off-by: Mark Herwege <[email protected]>
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I'd say that this is a pretty important fix, so it should get priority. |
* fix potential eternal loop on empty peristence * tests Signed-off-by: Mark Herwege <[email protected]>
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Merged an backported to 5.0.x. Not sure what to do with 4.3 - the code seems to be same there. I have not checked if tests make sense on 4.3.x. |
I doubt back porting the tests makes much sense. There had been change to the code between 4.3 and 5.0 in this area, so back porting the fix will have to be a new PR against 4.3. The offending code had been there for more than 3 years already. So, should I do it? |
With an issue like this, I'd say: absolutely. Just drop the tests and backport the fix. |
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This pull request has been mentioned on openHAB Community. There might be relevant details there: |
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This pull request has been mentioned on openHAB Community. There might be relevant details there: https://community.openhab.org/t/high-cpu-usage-since-upgrade-to-5-0-1/165989/31 |
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I'll label this as backported4 although this is done via separate PR #5019 (w/o the tests introduced for 5.x). |
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This pull request has been mentioned on openHAB Community. There might be relevant details there: |
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This pull request has been mentioned on openHAB Community. There might be relevant details there: https://community.openhab.org/t/high-cpu-load-unresponsive-oh-since-upgrade-even-with-5-0-2/167055/1 |
If an item has no values persisted, the
lastUpdate,lastChangeandpreviousStatepersistence extensions could get into an infinite loop. This could also happen when the query to the persistence service fails when called from these extension methods, e.g. because the database is offline.Resolves openhab/openhab-addons#19313
See https://community.openhab.org/t/high-cpu-usage-since-upgrade-to-5-0-1/165989/20?u=mherwege
See https://community.openhab.org/t/high-cpu-usage-when-calling-lastupdate-on-offline-influxdb-database/166198
Also see https://community.openhab.org/t/averagesince-calculation-wrong-if-no-measurements-in-timerange-available/166177/12. This PR adds some tests that look for the described behaviour in the community post. The tests did not reveal the issue so far.
If accepted, this should be backported.
@Nadahar @jimtng FYI