> On Jan. 7, 2016, 3:21 p.m., Maxim Khutornenko wrote: > > src/main/java/org/apache/aurora/scheduler/storage/db/DbModule.java, line 126 > > <https://reviews.apache.org/r/42041/diff/1/?file=1186513#file1186513line126> > > > > Are there any perf implications from having it ON by default? Should it > > be a configurable flag instead? > > Zameer Manji wrote: > Good question, I'll run benchmarks and update the testing done. > > John Sirois wrote: > And if there are perf implications, there is always [`SET > QUERY_STATISTICS`](http://www.h2database.com/html/grammar.html?highlight=QUERY_STATISTICS&search=QUERY_STATISTICS#set_query_statistics) > via the /h2console - and maybe that could just be documented as an ad-hoc > option.
John, using `SET QUERY_STATISTICS` will not persist across failovers and is not retroactive. This means operators need to run `SET QUERY_STATISTICS` and wait for data to be collected if they notice the scheduler is slower than expected. If this option is set when the database is created the data collected should reflect all operations done by the scheduler and that is more useful for triaging slow scheduling in large clusters. I think providing a flag or enabling it by default (pending results of benchmarks) are better solutions. - Zameer ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/42041/#review113355 ----------------------------------------------------------- On Jan. 7, 2016, 3:14 p.m., Zameer Manji wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/42041/ > ----------------------------------------------------------- > > (Updated Jan. 7, 2016, 3:14 p.m.) > > > Review request for Aurora, John Sirois and Maxim Khutornenko. > > > Repository: aurora > > > Description > ------- > > With this enabled operators can visit the H2 console at /h2console and run > queries like `SELECT * FROM INFORMATION_SCHEMA.QUERY_STATISTICS ORDER BY > MAX_EXECUTION_TIME DESC;` to diagnose slow schedulers. > > > Diffs > ----- > > src/main/java/org/apache/aurora/scheduler/storage/db/DbModule.java > e3efbdb80d8b18312bf1589eef883cdeee65b225 > > Diff: https://reviews.apache.org/r/42041/diff/ > > > Testing > ------- > > Ran `SELECT * FROM INFORMATION_SCHEMA.QUERY_STATISTICS ORDER BY > MAX_EXECUTION_TIME DESC;` within vagrant and saw query statistics. > > > Thanks, > > Zameer Manji > >
