You can try to use TRACING to debug the situation, but for a LWT to fail so fast, the most probable cause is what you stated: "It is possible that there are concurrent inserts on the same PK - actually thats the reason why I use LWTs." AKA, someone inserted first.
Regards, Carlos Juzarte Rolo Cassandra Consultant / Datastax Certified Architect / Cassandra MVP Pythian - Love your data rolo@pythian | Twitter: @cjrolo | Skype: cjr2k3 | Linkedin: *linkedin.com/in/carlosjuzarterolo <http://linkedin.com/in/carlosjuzarterolo>* Mobile: +351 918 918 100 www.pythian.com On Wed, Apr 12, 2017 at 3:51 PM, Roland Otta <roland.o...@willhaben.at> wrote: > sorry .. ignore my comment ... > > i missed your comment that the record is in the table ... > > On Wed, 2017-04-12 at 16:48 +0200, Roland Otta wrote: > > Hi Benjamin, > > its unlikely that i can assist you .. but nevertheless ... i give it a try > ;-) > > whats your consistency level for the insert? > what if one ore more nodes are marked down and proper consistency cant be > achieved? > of course the error message does not indicate that problem (as it says its > a timeout)... but in that case you would get an instant error for inserts. > wouldn't you? > > br, > roland > > > > On Wed, 2017-04-12 at 15:09 +0200, benjamin roth wrote: > > Hi folks, > > Can someone explain why that occurs? > > Write timeout after 0.006s > Query: 'INSERT INTO log_moment_import ("source", "reference", "user_id", > "moment_id", "date", "finished") VALUES (3, '1305821272790495', 65675537, > 0, '2017-04-12 13:00:51', NULL) IF NOT EXISTS > Primary key and parition key is source + reference > Message: Operation timed out - received only 1 responses. > > This appears every now and then in the log. When I check the for the > record in the table, it is there. > I could explain that, if the WTE occured after the configured write > timeout but it happens withing a few milliseconds. > Is this caused by lock contention? It is possible that there are > concurrent inserts on the same PK - actually thats the reason why I use > LWTs. > > Thanks! > > -- --
