Hi Jason, There is no command to have Kudu evict its block cache, but restarting the tablet server process will have that effect. Ideally all written data will be flushed before the restart, otherwise startup/bootstrap will take a bit longer. Flushing typically happens within 60s of the last write. Waiting for flush and compaction is also a best-practice for read-only benchmarks. I'm not sure if someone else on the list has an easier way of determining when a flush happens, but I typically look at the 'MemRowSet' memory usage for the tablet on the /mem-trackers HTTP endpoint; it should show something minimal like 256B if it's fully flushed and empty. You can also see details about how much memory is in the block cache on that page, if that interests you.
- Dan On Thu, Apr 6, 2017 at 11:23 PM, Jason Heo <jason.heo....@gmail.com> wrote: > Hi. > > I'm using Apache Kudu 1.2 on CDH 5.10. > > Currently, I'm doing a performance test of Kudu. > > Flushing OS Page Cache is easy, but I don't know how to flush > `block_cache_capacity_mb` easily. > > I currently execute SELECT statement over a unnecessarily table to evict > cached block of testing table. > > It is cumbersome, so I'd like to know is there a command for flushing > block caches (or another kudu's caches which I don't know yet) > > Thanks. > > Regards, > Jason >
