1 minute read

We assumed that the bug was caused mainly because of the high load rate , and that once the bulk of the data will be in HBase and the load will drop considerably , we won’t see it again.

Unfortunately , That didn’t happened. The bug happened again on our production-like environment , and that’s not something we could live with. As I mentioned before , similar issues seem to already be on the HBase Jira (HBASE-1061, HBASE-1094 - opened by me , this thread) .

To the best of my understanding , what actually happens is this: The batchUpdate is trying to address a region that has already been closed (Probably by a split) . We’re quite sure the problem is on the client-side - because restarting the client will usually solve the problem.

  • First option : the batchUpdate request is being done just a moment before the split is initiated , an thus it gets a reference to a region that was running when the request was performed , but it was closed soon afterward. I don’t really think this is the case because to the best of my log files , sometimes the failure happends not during any split.</p>
  • Second option : the batchUpdate is using a stale regionServers map - which brings up the question”why?” , when was it supposed to update , and why didn’t it do it?
  • Third option : the .META. table holds stale regions data - i.e there was a split , but it wasn’t updated. I find it hard to believe this is the case , becuase restarting the client solves the bug , and this behaviour can not be explained in this case.

We decided to try and solve the bug (or try until someone else solves it) - I’ll try to keep updating about our progress

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