Because the file only preserve the "key" of records, not the whole record. Records for those saved key will be loaded into cassandra during the startup of cassandra.
On Wed, Aug 17, 2011 at 5:52 PM, Yan Chunlu <springri...@gmail.com> wrote: > but the data size in the saved_cache are relatively small: > > will that cause the load problem? > > ls -lh /cassandra/saved_caches/ > total 32M > -rw-r--r-- 1 cass cass 2.9M 2011-08-12 19:53 > cass-CommentSortsCache-KeyCache > -rw-r--r-- 1 cass cass 2.9M 2011-08-17 04:29 > cass-CommentSortsCache-RowCache > -rw-r--r-- 1 cass cass 2.7M 2011-08-12 18:50 cass-CommentVote-KeyCache > -rw-r--r-- 1 cass cass 140K 2011-08-12 19:53 cass-device_images-KeyCache > -rw-r--r-- 1 cass cass 33K 2011-08-12 18:51 cass-Hide-KeyCache > -rw-r--r-- 1 cass cass 4.6M 2011-08-12 19:53 cass-images-KeyCache > -rw-r--r-- 1 cass cass 2.6M 2011-08-12 19:53 cass-LinksByUrl-KeyCache > -rw-r--r-- 1 cass cass 2.5M 2011-08-12 18:50 cass-LinkVote-KeyCache > -rw-r--r-- 1 cass cass 7.5M 2011-08-12 18:50 cass-cache-KeyCache > -rw-r--r-- 1 cass cass 3.7M 2011-08-12 21:51 cass-cache-RowCache > -rw-r--r-- 1 cass cass 1.8M 2011-08-12 18:51 cass-Save-KeyCache > -rw-r--r-- 1 cass cass 111K 2011-08-12 19:50 cass-SavesByAccount-KeyCache > -rw-r--r-- 1 cass cass 864 2011-08-12 19:49 cass-VotesByDay-KeyCache > -rw-r--r-- 1 cass cass 249K 2011-08-12 19:49 cass-VotesByLink-KeyCache > -rw-r--r-- 1 cass cass 28 2011-08-14 12:50 > system-HintsColumnFamily-KeyCache > -rw-r--r-- 1 cass cass 5 2011-08-14 12:50 system-LocationInfo-KeyCache > -rw-r--r-- 1 cass cass 54 2011-08-13 13:30 system-Migrations-KeyCache > -rw-r--r-- 1 cass cass 76 2011-08-13 13:30 system-Schema-KeyCache > > On Wed, Aug 17, 2011 at 4:31 PM, aaron morton <aa...@thelastpickle.com> > wrote: > > If you have a node that cannot start up due to issues loading the saved > cache delete the files in the saved_cache directory before starting it. > > > > The settings to save the row and key cache are per CF. You can change > them with an update column family statement via the CLI when attached to any > node. You may then want to check the saved_caches directory and delete any > files that are left (not sure if they are automatically deleted). > > > > i would recommend: > > - stop node 2 > > - delete it's saved_cache > > - make the schema change via another node > > - startup node 2 > > > > Cheers > > > > ----------------- > > Aaron Morton > > Freelance Cassandra Developer > > @aaronmorton > > http://www.thelastpickle.com > > > > On 17/08/2011, at 2:59 PM, Yan Chunlu wrote: > > > >> does this need to be cluster wide? or I could just modify the caches > >> on one node? since I could not connect to the node with > >> cassandra-cli, it says "connection refused" > >> > >> > >> [default@unknown] connect node2/9160; > >> Exception connecting to node2/9160. Reason: Connection refused. > >> > >> > >> so if I change the cache size via other nodes, how could node2 be > >> notified the changing? kill cassandra and start it again could make > >> it update the schema? > >> > >> > >> > >> On Wed, Aug 17, 2011 at 5:59 AM, Teijo Holzer <thol...@wetafx.co.nz> > wrote: > >>> Hi, > >>> > >>> yes, we saw exactly the same messages. We got rid of these by doing the > >>> following: > >>> > >>> * Set all row & key caches in your CFs to 0 via cassandra-cli > >>> * Kill Cassandra > >>> * Remove all files in the saved_caches directory > >>> * Start Cassandra > >>> * Slowly bring back row & key caches (if desired, we left them off) > >>> > >>> Cheers, > >>> > >>> T. > >>> > >>> On 16/08/11 23:35, Yan Chunlu wrote: > >>>> > >>>> I saw alot slicequeryfilter things if changed the log level to DEBUG. > >>>> just > >>>> thought even bring up a new node will be faster than start the old > >>>> one..... it > >>>> is wired > >>>> > >>>> DEBUG [main] 2011-08-16 06:32:49,213 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:225@1313068845474382 > >>>> DEBUG [main] 2011-08-16 06:32:49,245 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:453@1310999270198313 > >>>> DEBUG [main] 2011-08-16 06:32:49,251 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:26@1313199902088827 > >>>> DEBUG [main] 2011-08-16 06:32:49,576 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:157@1313097239332314 > >>>> DEBUG [main] 2011-08-16 06:32:50,674 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:41729@1313190821826229 > >>>> DEBUG [main] 2011-08-16 06:32:50,811 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:6@1313174157301203 > >>>> DEBUG [main] 2011-08-16 06:32:50,867 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:98@1312011362250907 > >>>> DEBUG [main] 2011-08-16 06:32:50,881 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:42@1313201711997005 > >>>> DEBUG [main] 2011-08-16 06:32:50,910 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:96@1312939986190155 > >>>> DEBUG [main] 2011-08-16 06:32:50,954 SliceQueryFilter.java (line 123) > >>>> collecting 0 of 2147483647: 76616c7565:false:621@1313192538616112 > >>>> > >>>> > >>>> > >>>> On Tue, Aug 16, 2011 at 7:32 PM, Yan Chunlu <springri...@gmail.com > >>>> <mailto:springri...@gmail.com>> wrote: > >>>> > >>>> but it seems the row cache is cluster wide, how will the change of > row > >>>> cache affect the read speed? > >>>> > >>>> > >>>> On Mon, Aug 15, 2011 at 7:33 AM, Jonathan Ellis <jbel...@gmail.com > >>>> <mailto:jbel...@gmail.com>> wrote: > >>>> > >>>> Or leave row cache enabled but disable cache saving (and remove > the > >>>> one already on disk). > >>>> > >>>> On Sun, Aug 14, 2011 at 5:05 PM, aaron morton > >>>> <aa...@thelastpickle.com > >>>> <mailto:aa...@thelastpickle.com>> wrote: > >>>> > INFO [main] 2011-08-14 09:24:52,198 ColumnFamilyStore.java > >>>> (line 547) > >>>> > completed loading (1744370 ms; 200000 keys) row cache for > >>>> COMMENT > >>>> > > >>>> > It's taking 29 minutes to load 200,000 rows in the row > cache. > >>>> Thats a > >>>> > pretty big row cache, I would suggest reducing or disabling > it. > >>>> > Background > >>>> > >>>> > http://www.datastax.com/dev/blog/maximizing-cache-benefit-with-cassandra > >>>> > > >>>> > and server can not afford the load then crashed. after come > >>>> back, > >>>> node 3 can > >>>> > not return for more than 96 hours > >>>> > > >>>> > Crashed how ? > >>>> > You may be seeing > >>>> https://issues.apache.org/jira/browse/CASSANDRA-2280 > >>>> > Watch nodetool compactionstats to see when the Merkle tree > build > >>>> finishes > >>>> > and nodetool netstats to see which CF's are streaming. > >>>> > Cheers > >>>> > ----------------- > >>>> > Aaron Morton > >>>> > Freelance Cassandra Developer > >>>> > @aaronmorton > >>>> > http://www.thelastpickle.com > >>>> > On 15 Aug 2011, at 04:23, Yan Chunlu wrote: > >>>> > > >>>> > > >>>> > I got 3 nodes and RF=3, when I repairing ndoe3, it seems > alot > >>>> data > >>>> > generated. and server can not afford the load then crashed. > >>>> > after come back, node 3 can not return for more than 96 > hours > >>>> > > >>>> > for 34GB data, the node 2 could restart and back online > within 1 > >>>> hour. > >>>> > > >>>> > I am not sure what's wrong with node3 and should I restart > node > >>>> 3 again? > >>>> > thanks! > >>>> > > >>>> > Address Status State Load Owns Token > >>>> > > >>>> > 113427455640312821154458202477256070484 > >>>> > node1 Up Normal 34.11 GB 33.33% 0 > >>>> > node2 Up Normal 31.44 GB 33.33% > >>>> > 56713727820156410577229101238628035242 > >>>> > node3 Down Normal 177.55 GB 33.33% > >>>> > 113427455640312821154458202477256070484 > >>>> > > >>>> > > >>>> > the log shows it is still going on, not sure why it is so > slow: > >>>> > > >>>> > > >>>> > INFO [main] 2011-08-14 08:55:47,734 SSTableReader.java > (line > >>>> 154) > >>>> Opening > >>>> > /cassandra/data/COMMENT > >>>> > INFO [main] 2011-08-14 08:55:47,828 ColumnFamilyStore.java > >>>> (line 275) > >>>> > reading saved cache /cassandra/saved_caches/COMMENT-RowCache > >>>> > INFO [main] 2011-08-14 09:24:52,198 ColumnFamilyStore.java > >>>> (line 547) > >>>> > completed loading (1744370 ms; 200000 keys) row cache for > >>>> COMMENT > >>>> > INFO [main] 2011-08-14 09:24:52,299 ColumnFamilyStore.java > >>>> (line 275) > >>>> > reading saved cache /cassandra/saved_caches/COMMENT-RowCache > >>>> > INFO [CompactionExecutor:1] 2011-08-14 10:24:55,480 > >>>> CacheWriter.java (line > >>>> > 96) Saved COMMENT-RowCache (200000 items) in 2535 ms > >>>> > > >>>> > > >>>> > > >>>> > > >>>> > > >>>> > > >>>> > >>>> > >>>> > >>>> -- > >>>> Jonathan Ellis > >>>> Project Chair, Apache Cassandra > >>>> co-founder of DataStax, the source for professional Cassandra > >>>> support > >>>> http://www.datastax.com > >>>> > >>>> > >>>> > >>> > >>> > > > > >
