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From Carlos Rolo <r...@pythian.com>
Subject Re: WriteTimeoutException with LWT after few milliseconds
Date Wed, 12 Apr 2017 15:41:49 GMT
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:
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On Wed, Apr 12, 2017 at 3:51 PM, Roland Otta <Roland.Otta@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!
>
>

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