Yes but adding the extra one ends up by * 1000. The limit in CQL3 specifies the number of logical rows, not the number of physical columns in the storage engine Le 24 juin 2014 08:30, "Kevin Burton" <bur...@spinn3r.com> a écrit :
> oh.. the difference between the the ONE field and the remaining 29 is > massive. > > It's like 200ms for just the 29 columns.. adding the extra one cause it to > timeout .. > 5000ms... > > > On Mon, Jun 23, 2014 at 10:30 PM, DuyHai Doan <doanduy...@gmail.com> > wrote: > >> Don't forget that when you do the Select with limit set to 1000, >> Cassandra is actually fetching 1000 * 29 physical columns (29 fields per >> logical row). >> >> Adding one extra big html column may be too much and cause timeout. Try >> to: >> >> 1. Select only the big html only >> 2. Or reduce the limit incrementally until no timeout >> Le 24 juin 2014 06:22, "Kevin Burton" <bur...@spinn3r.com> a écrit : >> >> I have a table with a schema mostly of small fields. About 30 of them. >>> >>> The primary key is: >>> >>> primary key( bucket, sequence ) >>> >>> … I have 100 buckets and the idea is that sequence is ever increasing. >>> This way I can read from bucket zero, and everything after sequence N and >>> get all the writes ordered by time. >>> >>> I'm running >>> >>> SELECT ... FROM content WHERE bucket=0 AND sequence>0 ORDER BY sequence >>> ASC LIMIT 1000; >>> >>> … using the have driver. >>> >>> If I add ALL the fields, except one, so 29 fields, the query is fast. >>> Only 129ms…. >>> >>> However, if I add the 'html' field, which is snapshot of HTML obvious, >>> the query times out… >>> >>> I'm going to add tracing and try to track it down further, but I suspect >>> I'm doing something stupid. >>> >>> Is it going to burn me that the data is UTF8 encoded? I can't image >>> decoding UTF8 is going to be THAT slow but perhaps cassandra is doing >>> something silly under the covers? >>> >>> cqlsh doesn't time out … it actually works fine but it uses 100% CPU >>> while writing out the data so it's not a good comparison unfortunately >>> >>> >>> ception in thread "main" >>> com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s) >>> tried for query failed (tried: ...:9042 >>> (com.datastax.driver.core.exceptions.DriverException: Timeout during read)) >>> at >>> com.datastax.driver.core.exceptions.NoHostAvailableException.copy(NoHostAvailableException.java:65) >>> at >>> com.datastax.driver.core.DefaultResultSetFuture.extractCauseFromExecutionException(DefaultResultSetFuture.java:256) >>> at >>> com.datastax.driver.core.DefaultResultSetFuture.getUninterruptibly(DefaultResultSetFuture.java:172) >>> at >>> com.datastax.driver.core.SessionManager.execute(SessionManager.java:92) >>> at >>> com.spinn3r.artemis.robot.console.BenchmarkContentStream.main(BenchmarkContentStream.java:100) >>> Caused by: com.datastax.driver.core.exceptions.NoHostAvailableException: >>> All host(s) tried for query failed (tried: >>> dev4.wdc.sl.spinn3r.com/10.24.23.94:9042 >>> (com.datastax.driver.core.exceptions.DriverException: Timeout during read)) >>> at >>> com.datastax.driver.core.RequestHandler.sendRequest(RequestHandler.java:103) >>> at com.datastax.driver.core.RequestHandler$1.run(RequestHandler.java:175) >>> at >>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) >>> at >>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) >>> at java.lang.Thread.run(Thread.java:724) >>> >>> >>> -- >>> >>> Founder/CEO Spinn3r.com >>> Location: *San Francisco, CA* >>> Skype: *burtonator* >>> blog: http://burtonator.wordpress.com >>> … or check out my Google+ profile >>> <https://plus.google.com/102718274791889610666/posts> >>> <http://spinn3r.com> >>> War is peace. Freedom is slavery. Ignorance is strength. Corporations >>> are people. >>> >>> > > > -- > > Founder/CEO Spinn3r.com > Location: *San Francisco, CA* > Skype: *burtonator* > blog: http://burtonator.wordpress.com > … or check out my Google+ profile > <https://plus.google.com/102718274791889610666/posts> > <http://spinn3r.com> > War is peace. Freedom is slavery. Ignorance is strength. Corporations are > people. > >
