I found out that if the WTEs occur, there was already another process inserting the same primary key because I found duplicates in some places that perfectly match the WTE logs.
Does anybody know, why this throws a WTE instead of returning [applied]' = false ? This is quite confusing! 2017-04-12 17:41 GMT+02:00 Carlos Rolo <r...@pythian.com>: > 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 <+351%20918%20918%20100> > 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! >> >> > > -- > > > >
