DB lock issue durring unit tests

[smuzaffar]

@ggovi , during PR tests of cms-data/RecoBTag-Combined#23 unit test testConditionDatabase_2 failed due to locking issue [a]. I think issue is that there are two tests ( https://github.com/cms-sw/cmssw/search?q=cms_conditions_3.db&unscoped_q=cms_conditions_3.db ) which are using cms_conditions_3.db file. Can you please provide a fix for this?

[a]

===== Test "testConditionDatabase_2" ====
> Connecting with db in sqlite_file:cms_conditions_3.db
CORAL/RelationalPlugins/sqlite Error SQLiteStatement::finalize 5 database is locked
CORAL/RelationalPlugins/sqlite Error SQLiteStatement::execute 5 database is locked
ERROR: database is locked ( CORAL : "SQLiteStatement::execute" from "CORAL/RelationalPlugins/sqlite" )

---> test testConditionDatabase_2 had ERRORS
 
^^^^ End Test testConditionDatabase_2 ^^^^

[cmsbuild]

A new Issue was created by @smuzaffar Malik Shahzad Muzaffar.

@davidlange6, @Dr15Jones, @smuzaffar, @fabiocos, @kpedro88 can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[smuzaffar]

assign db

[cmsbuild]

New categories assigned: db

@ggovi you have been requested to review this Pull request/Issue and eventually sign? Thanks

[fabiocos]

Any idea why is this appearing just now? This code seems untouched since a while...

[smuzaffar]

This is just race condition. If both tests run on same time then there is a chance that there will be lock on the local db file.

[fabiocos]

@smuzaffar yes, I understand that, the point is why it starts to systematically hit us now...

[smuzaffar]

is it very frequent now?

[smuzaffar]

the second test was added on Jan 23 this year ( #25722 )

[fabiocos]

well I would say we are seeing it in several PR tests, while this was not the case until recently. But the IB looks clean from this point of view, are unit tests run there differently?

[smuzaffar]

No, unit tests in IBs are run the same way. Only thing is that in IBs we run all tests that is why there is less chance of collision.

[smuzaffar]

#26762 should fix this issue

[smuzaffar]

this has been fixes via #26762