Write performance decreases. Reads are basically blocked, too. Sometimes I have to wait 3-4 seconds to get a count even though there're only couple of thousand small entries in a table.
On Thu, Apr 18, 2013 at 8:37 PM, aaron morton <[email protected]>wrote: > After about 1-2K inserts I get significant performance decrease. > > A decrease in performance doing what ? > > Cheers > > ----------------- > Aaron Morton > Freelance Cassandra Consultant > New Zealand > > @aaronmorton > http://www.thelastpickle.com > > On 19/04/2013, at 4:43 AM, Oleksandr Petrov <[email protected]> > wrote: > > Hi, > > I'm trying to persist some event data, I've tried to identify the > bottleneck, and it seems to work like that: > > If I create a table with primary key based on (application, environment, > type and emitted_at): > > CREATE TABLE events (application varchar, environment varchar, type > varchar, additional_info map<varchar, varchar>, hostname varchar, > emitted_at timestamp, > *PRIMARY KEY (application, environment, type, emitted_at));* > > And insert events via CQL, prepared statements: > > INSERT INTO events (environment, application, hostname, emitted_at, type, > additional_info) VALUES (?, ?, ?, ?, ?, ?); > > Values are: "local" "analytics" "noname" #inst "2013-04-18T16:37:02.723-00:00" > "event_type" {"some" "value"} > > After about 1-2K inserts I get significant performance decrease. > > I've tried using only emitted_at (timestamp) as a primary key, OR writing > additional_info data as a serialized JSON (varchar) instead of Map. Both > scenarios seem to solve the performance degradation. > > I'm using Cassandra 1.2.3 from DataStax repository, running it on 2-core > machine with 2GB Ram. > > What could I do wrong here? What may cause performance issues?.. > Thank you > > > -- > alex p > > > -- alex p
