Post the server logs and traces of one of the lengthy queries? On 15 Mar 2014 20:49, "Batranut Bogdan" <batra...@yahoo.com> wrote:
> Hello, > > Yes for the first query the server can be slow but no matter what is > should not take 10 seconds to get one key from a column family. I can see > this happening if I have times like 20 ms for some queries and let's say > 300 ms for uncached ones. But I have responses that take from 8 to 20 ms > (420 out of 450 queries) and 30 response that take from 5 to 13 seconds. It > is this HUGE difference that bothers me. > > > On Friday, March 14, 2014 9:18 PM, Manoj Khangaonkar < > khangaon...@gmail.com> wrote: > > > > I have ~450 queries that are like this: SELECT * FROM table where key = > 'some string' and ts = some value; some value is close to present time. > > The problem: > > About 10 - 20 % of these queries take more than 5 seconds to execute, in > fact, the majority of those take around 10 seconds. > When investigating I saw that if I have a slow response and I redo the > query it will finish in 8 - 10 MILIseconds like the rest of the queries > that I have. > > > > Most likely for the first slow query, the server has to go looking in > SSTables on disk. 2nd fast response is returned from memory. I am not sure > how much data each node is managing. But try adding more nodes , so that > each node is managing fewer keys. More nodes with recommended heap size of > 8G is better than fewer nodes with bigger heap size. > > regards > > -- > http://khangaonkar.blogspot.com/ > > >
