> > I suspect it is slowness related to storage access. > I was not able to find any logs or tweaks to log "slow storage" > access, does such a thing exist? > I believe I have seen warnings for slow syncs from the hdfs layer, but don't remember any for the read path.
And something else that'd help me: Can anyone point me (if it exists) at the (vicinity of the) code that actually reads from HDFS at the end? There are so many layers. I think you might be interested in the HFileBlock.readBlockData(). I can see we are open a FSDataInputStream there, then pass to some other methods, using byte buffers and hadoop IOUtils to read from hdfs. Em ter., 5 de dez. de 2023 às 20:46, Lars Francke <[email protected]> escreveu: > Hi, > > I am debugging an issue where we see some Get requests taking 2-5s. > We do see "responseTooSlow" etc. and this is in an environment where I > cannot run a Profiler but I _can_ run modified code. > > So what I did was I added a stupid "MethodTimer"[1] which records how > long certain operations take at various points in the code (e.g. [2]). > I've been doing this a few rounds and have now arrived at the StoreScanner. > > I'm wondering if anyone has better ideas on how to diagnose this? > I am a HBase committer but I haven't been able to keep up with the > changes in the last 5-6 years so I'm not too familiar with the inner > workings anymore and would appreciate a hint. > > I suspect it is slowness related to storage access. > I was not able to find any logs or tweaks to log "slow storage" > access, does such a thing exist? > And something else that'd help me: Can anyone point me (if it exists) > at the (vicinity of the) code that actually reads from HDFS at the > end? There are so many layers. > > Thank you! > > Cheers, > Lars > > > [1] < > https://github.com/stackabletech/docker-images/blob/8349f29f8aded8a01a8d1dbf7a90776ede1764ca/hbase/stackable/patches/2.4.12/005-STACKABLE-profiling-2.4.12.patch#L150C5-L150C5 > > > [2] < > https://github.com/stackabletech/docker-images/blob/8349f29f8aded8a01a8d1dbf7a90776ede1764ca/hbase/stackable/patches/2.4.12/005-STACKABLE-profiling-2.4.12.patch#L289-L297 > > >
