Try: keyspace: "Analytics" key: "o:movie" column family: "movie" super column: "all"
I was able to get timeouts with a few concurrent get_slice() calls (3-4 with debug logging, 6 without) on the super column, with start = "", finish = "", and count = 1. Edmond On Thu, Oct 22, 2009 at 7:42 AM, Jonathan Ellis <[email protected]> wrote: > What is your columnfamily definition? What query should I test with? > > On Wed, Oct 21, 2009 at 7:33 PM, Edmond Lau <[email protected]> wrote: >> On Tue, Oct 20, 2009 at 2:03 PM, Jonathan Ellis <[email protected]> wrote: >>> Okay, so we have 2 problems: >>> >>> - the read is simply too slow >>> - we're doing unnecessary(?) read repairs >>> >>> For the first I think it's going to be easiest if you can export the >>> row in question so we can do some profiling. (Eric will have a tool >>> to do this soon.) >> >> Ok - I've created a cassandra setup with just the row in question and >> tarred up the data + storage-conf.xml for the three nodes: >> >> http://demo.ooyala.com/cassandra/cassandra-1.tgz >> http://demo.ooyala.com/cassandra/cassandra-2.tgz >> http://demo.ooyala.com/cassandra/cassandra-3.tgz >> >>> >>> For the second, how sure are you that the repair is unnecessary? Does >>> it repeat the repair when you do the query again after letting the >>> callbacks complete? >> >> I didn't do any writes as I was debugging the issue whereas I was >> reading the same data a whole bunch of times, so the repair should've >> been unnecessary. >> >> Thanks for your help, >> Edmond >> >>> >>> -Jonathan >>> >>> On Mon, Oct 19, 2009 at 11:38 PM, Edmond Lau <[email protected]> wrote: >>>> A single local read with debug logging takes 3-4 secs on the node with >>>> 3 data files. It actually takes roughly as long on the other nodes as >>>> well (I was incorrect in saying that they were fast). >>>> >>>> DEBUG [pool-1-thread-22] 2009-10-20 04:26:06,953 CassandraServer.java >>>> (line 219) get_slice >>>> DEBUG [pool-1-thread-22] 2009-10-20 04:26:06,955 StorageProxy.java >>>> (line 468) weakreadlocal reading >>>> SliceFromReadCommand(table='Analytics', key='o:movie', >>>> column_parent='QueryPath(columnFamilyName='movie', >>>> superColumnName='[...@26e00675', columnName='null')', start='', >>>> finish='', reversed=false, count=1) >>>> DEBUG [pool-1-thread-22] 2009-10-20 04:26:10,382 SliceQueryFilter.java >>>> (line 115) collecting 1000036:false:5...@1255978226411394 >>>> DEBUG [CONSISTENCY-MANAGER:2] 2009-10-20 04:26:10,383 >>>> ConsistencyManager.java (line 168) Reading consistency digest for >>>> o:movie from 2...@[172.16.129.71:7000, 172.16.129.72:7000] >>>> DEBUG [RESPONSE-STAGE:1] 2009-10-20 04:26:13,332 >>>> ResponseVerbHandler.java (line 34) Processing response on a callback >>>> from [email protected]:7000 >>>> DEBUG [RESPONSE-STAGE:3] 2009-10-20 04:26:13,675 >>>> ResponseVerbHandler.java (line 34) Processing response on a callback >>>> from [email protected]:7000 >>>> DEBUG [RESPONSE-STAGE:3] 2009-10-20 04:26:13,677 >>>> ConsistencyManager.java (line 96) Performing read repair for o:movie >>>> to 2...@[172.16.129.71:7000, 172.16.129.72:7000, 172.16.129.75:7000] >>>> >>>> Also, it's unclear why there's a read repair going on above, since I >>>> haven't made any updates. >>>> >>>> Doing a quorum read on the node with 3 data files takes 7 seconds w/ >>>> debug logging and leads to a DigestMismatchException, again even >>>> though I haven't made any updates. >>>> >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:00,892 CassandraServer.java >>>> (line 219) get_slice >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:00,894 StorageProxy.java >>>> (line 374) strongread reading data for >>>> SliceFromReadCommand(table='Analytics', key='o:movie', >>>> column_parent='QueryPath(columnFamilyName='movie', >>>> superColumnName='[...@2cf50c5f', columnName='null')', start='', >>>> finish='', reversed=false, count=1) from [email protected]:7000 >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:00,894 StorageProxy.java >>>> (line 381) strongread reading digest for >>>> SliceFromReadCommand(table='Analytics', key='o:movie', >>>> column_parent='QueryPath(columnFamilyName='movie', >>>> superColumnName='[...@2cf50c5f', columnName='null')', start='', >>>> finish='', reversed=false, count=1) from [email protected]:7000 >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:00,895 StorageProxy.java >>>> (line 381) strongread reading digest for >>>> SliceFromReadCommand(table='Analytics', key='o:movie', >>>> column_parent='QueryPath(columnFamilyName='movie', >>>> superColumnName='[...@2cf50c5f', columnName='null')', start='', >>>> finish='', reversed=false, count=1) from [email protected]:7000 >>>> DEBUG [RESPONSE-STAGE:3] 2009-10-20 04:30:03,994 >>>> ResponseVerbHandler.java (line 34) Processing response on a callback >>>> from [email protected]:7000 >>>> DEBUG [RESPONSE-STAGE:2] 2009-10-20 04:30:04,107 >>>> ResponseVerbHandler.java (line 34) Processing response on a callback >>>> from [email protected]:7000 >>>> DEBUG [ROW-READ-STAGE:9] 2009-10-20 04:30:04,787 SliceQueryFilter.java >>>> (line 115) collecting 1000036:false:5...@1255978226411394 >>>> DEBUG [ROW-READ-STAGE:9] 2009-10-20 04:30:04,788 ReadVerbHandler.java >>>> (line 100) Read key o:movie; sending response to >>>> [email protected]:7000 >>>> DEBUG [RESPONSE-STAGE:4] 2009-10-20 04:30:04,788 >>>> ResponseVerbHandler.java (line 34) Processing response on a callback >>>> from [email protected]:7000 >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:04,789 >>>> ReadResponseResolver.java (line 84) Response deserialization time : 0 >>>> ms. >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:04,790 >>>> ReadResponseResolver.java (line 84) Response deserialization time : 0 >>>> ms. >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:04,791 >>>> ReadResponseResolver.java (line 84) Response deserialization time : 1 >>>> ms. >>>> INFO [pool-1-thread-25] 2009-10-20 04:30:04,792 StorageProxy.java >>>> (line 410) DigestMismatchException: o:movie >>>> DEBUG [RESPONSE-STAGE:1] 2009-10-20 04:30:07,953 >>>> ResponseVerbHandler.java (line 34) Processing response on a callback >>>> from [email protected]:7000 >>>> DEBUG [RESPONSE-STAGE:3] 2009-10-20 04:30:08,130 >>>> ResponseVerbHandler.java (line 34) Processing response on a callback >>>> from [email protected]:7000 >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:08,132 >>>> ReadResponseResolver.java (line 84) Response deserialization time : 1 >>>> ms. >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:08,132 >>>> ReadResponseResolver.java (line 84) Response deserialization time : 0 >>>> ms. >>>> DEBUG [pool-1-thread-25] 2009-10-20 04:30:08,132 >>>> ReadResponseResolver.java (line 149) resolve: 1 ms. >>>> DEBUG [ROW-READ-STAGE:10] 2009-10-20 04:30:08,235 >>>> SliceQueryFilter.java (line 115) collecting >>>> 1000036:false:5...@1255978226411394 >>>> DEBUG [ROW-READ-STAGE:10] 2009-10-20 04:30:08,235 ReadVerbHandler.java >>>> (line 100) Read key o:movie; sending response to >>>> [email protected]:7000 >>>> >>>> Edmond >>>> >>>> On Mon, Oct 19, 2009 at 8:04 PM, Jonathan Ellis <[email protected]> wrote: >>>>> On Mon, Oct 19, 2009 at 9:48 PM, Edmond Lau <[email protected]> wrote: >>>>>> 8 data files total. 3 nodes have 1, 1 has 2, the 3rd has 3. >>>>>> >>>>>>> Does it still take ~8s if you direct a CL.ONE query at one of the >>>>>>> nodes you know has the data (i.e., a local read)? >>>>>> >>>>>> Local reads return quickly, but if you look at the logs below, there's >>>>>> 6 secs from when cassandra prints that it's reading a consistency >>>>>> digest to when it processes a callback. >>>>> >>>>> That's from when it sends the digest command, to when it gets a callback. >>>>> >>>>> Something doesn't add up. If computing &sending a digest response >>>>> takes 6s, either reading the row or computing the digest must be >>>>> taking substantial time. But if local reads are fast, it's not >>>>> reading the row that is slow, and if resolve is fast (from your logs, >>>>> it is 2ms) then it's not computing the digest that is slow. >>>>> >>>>> Try doing a local read from the node with 3 data files, see if that is >>>>> slower. >>>>> >>>>> If you still see a fast read there, add some more debug logging in >>>>> ReadVerbHandler.java, where it says something like (I'm going from >>>>> trunk here but 0.4.1 is similar) >>>>> >>>>> Row row = readCommand.getRow(table); >>>>> ReadResponse readResponse; >>>>> if (readCommand.isDigestQuery()) >>>>> { >>>>> readResponse = new ReadResponse(row.digest()); >>>>> >>>>> time the getRow and the row.digest() calls and log how long those take >>>>> in the quorum scenario. >>>>> >>>>> -Jonathan >>>>> >>>> >>> >> >
