Re: Creating secondary index CQL3 cassandra 1.1.1
On Thu, Jun 21, 2012 at 5:11 AM, Stephen Powis stephen.po...@pardot.com wrote: I have the following schema: describe columnfamily visitor_audit; CREATE TABLE visitor_audit ( visitor_id text, audit_id uuid, account_id int, audit_type int, created_at text, PRIMARY KEY (visitor_id, audit_id) ) WITH comment='' AND caching='KEYS_ONLY' AND read_repair_chance=0.10 AND gc_grace_seconds=864000 AND min_compaction_threshold=4 AND max_compaction_threshold=32 AND replicate_on_write='true' AND compaction_strategy_class='SizeTieredCompactionStrategy' AND compression_parameters:sstable_compression='SnappyCompressor'; I then created an index by executing the following: CREATE INDEX ix_accountid ON visitor_audit (account_id); When I attempt to execute: select * from visitor_audit where account_id=1; Nothing is returned even tho I have rows with account_id equal to 1. Is there anything I am missing here? You are pretty much hitting https://issues.apache.org/jira/browse/CASSANDRA-4328. In other words, secondary indexes is not yet supported on table with composite PRIMARY KEY, but we don't correctly reject the CREATE INDEX command. -- Sylvain
Re: When will CQL BATCH support binding variable (Query substitution use named parameters)?
On Thu, Jun 21, 2012 at 12:06 AM, Data Craftsman database.crafts...@gmail.com wrote: Hello, CQL BATCH is good for INSERT/UPDATE performance. But it cannot do binding variable, exposed to SQL injection. Is there a plan to make CQL BATCH to support binding variable in near future? e.g. http://code.google.com/a/apache-extras.org/p/cassandra-dbapi2/ Query substitution Use named parameters and a dictionary of names and values. cursor.execute(SELECT column FROM CF WHERE name=:name, dict(name=Foo)) That may be a problem with the python driver (cassandra-dbapi2) and you'd want to open an issue there. But note that the query substitution of the python driver is *not* related to CQL prepared statements (that use question marks for bound variables). Those support BATCH all right. -- Sylvain
Re: cqlsh commands
You should be able to get most of this information from the datastax documentation, e.g. http://www.datastax.com/docs/1.0/references/cql/index for version 1.0. Jeff On Jun 20, 2012, at 1:47 PM, Thierry Templier wrote: Hello, I'm using cqlsh tool to create column families and it works fine. However I don't know how to use the following commands: Documented commands (type help topic): ASSUME CAPTURE DESC DESCRIBE EXIT HELP SELECT SHOW SOURCE USE Moreover I can't display the related documentations using the help command. Thanks very much for your help. Thierry
Tiered compation on two disks
Hi, I have a Cassandra installation where we plan to store 1Tb of data, split between two 1Tb disks. Tiered compation should be better suited for our workload (append-only, deletion of old data, few reads). I know that tiered compaction needs 50% free disk space for worst case situation. How does this combine with the disk split? What happens if I have 500Gb of data in one disk and 500Gb in the other? Won't compaction try to build a single 1Tb file, failing since there are only 500Gb free on each disk? Flavio
Starting cassandra with -D option
Hi Folks, We wanted to have a single cassandra installation, and use it to start cassandra in other nodes by passing it the cassandra configuration directories as a parameter. Idea is to avoid having the copies of cassandra code in each node, and starting each node by getting into bin/cassandra of that node. As per http://www.datastax.com/docs/1.0/references/cassandra, We have an option –D where we can supply some parameters to cassandra. Has anyone tried this? Im getting an error as below. walmarts-MacBook-Pro-2:Node1-Cassandra1.1.0 walmart$ bin/cassandra -Dcassandra.config=file:///Users/walmart/Downloads/Cassandra/Node2-Cassandra1.1.0/conf walmarts-MacBook-Pro-2:Node1-Cassandra1.1.0 walmart$ INFO 15:38:01,763 Logging initialized INFO 15:38:01,766 JVM vendor/version: Java HotSpot(TM) 64-Bit Server VM/1.6.0_31 INFO 15:38:01,766 Heap size: 1052770304/1052770304 INFO 15:38:01,766 Classpath: bin/../conf:bin/../build/classes/main:bin/../build/classes/thrift:bin/../lib/antlr-3.2.jar:bin/../lib/apache-cassandra-1.1.0.jar:bin/../lib/apache-cassandra-clientutil-1.1.0.jar:bin/../lib/apache-cassandra-thrift-1.1.0.jar:bin/../lib/avro-1.4.0-fixes.jar:bin/../lib/avro-1.4.0-sources-fixes.jar:bin/../lib/commons-cli-1.1.jar:bin/../lib/commons-codec-1.2.jar:bin/../lib/commons-lang-2.4.jar:bin/../lib/compress-lzf-0.8.4.jar:bin/../lib/concurrentlinkedhashmap-lru-1.2.jar:bin/../lib/guava-r08.jar:bin/../lib/high-scale-lib-1.1.2.jar:bin/../lib/jackson-core-asl-1.9.2.jar:bin/../lib/jackson-mapper-asl-1.9.2.jar:bin/../lib/jamm-0.2.5.jar:bin/../lib/jline-0.9.94.jar:bin/../lib/json-simple-1.1.jar:bin/../lib/libthrift-0.7.0.jar:bin/../lib/log4j-1.2.16.jar:bin/../lib/metrics-core-2.0.3.jar:bin/../lib/mx4j-tools-3.0.1.jar:bin/../lib/servlet-api-2.5-20081211.jar:bin/../lib/slf4j-api-1.6.1.jar:bin/../lib/slf4j-log4j12-1.6.1.jar:bin/../lib/snakeyaml-1.6.jar:bin/../lib/snappy-java-1.0.4.1.jar:bin/../lib/snaptree-0.1.jar:bin/../lib/jamm-0.2.5.jar INFO 15:38:01,768 JNA not found. Native methods will be disabled. INFO 15:38:01,826 Loading settings from file:/Users/walmart/Downloads/Cassandra/Node2-Cassandra1.1.0/conf ERROR 15:38:01,873 Fatal configuration error error Can't construct a java object for tag:yaml.org,2002:org.apache.cassandra.config.Config; exception=No single argument constructor found for class org.apache.cassandra.config.Config in reader, line 1, column 1: cassandra.yaml The other option would be to modify cassandra.in.sh. Has anyone tried this?? Regards, Roshni This email and any files transmitted with it are confidential and intended solely for the individual or entity to whom they are addressed. If you have received this email in error destroy it immediately. *** Walmart Confidential ***
Re: Starting cassandra with -D option
The option must actually include also the name of the yaml file: Dcassandra.config=file:///Users/walmart/Downloads/Cassandra/Node2-Cassandra1.1.0/conf/cassandra.yaml Flavio Il 6/21/2012 13:16 PM, Roshni Rajagopal ha scritto: Hi Folks, We wanted to have a single cassandra installation, and use it to start cassandra in other nodes by passing it the cassandra configuration directories as a parameter. Idea is to avoid having the copies of cassandra code in each node, and starting each node by getting into bin/cassandra of that node. As per http://www.datastax.com/docs/1.0/references/cassandra, We have an option –D where we can supply some parameters to cassandra. Has anyone tried this? Im getting an error as below. walmarts-MacBook-Pro-2:Node1-Cassandra1.1.0 walmart$ bin/cassandra -Dcassandra.config=file:///Users/walmart/Downloads/Cassandra/Node2-Cassandra1.1.0/conf walmarts-MacBook-Pro-2:Node1-Cassandra1.1.0 walmart$ INFO 15:38:01,763 Logging initialized INFO 15:38:01,766 JVM vendor/version: Java HotSpot(TM) 64-Bit Server VM/1.6.0_31 INFO 15:38:01,766 Heap size: 1052770304/1052770304 INFO 15:38:01,766 Classpath: bin/../conf:bin/../build/classes/main:bin/../build/classes/thrift:bin/../lib/antlr-3.2.jar:bin/../lib/apache-cassandra-1.1.0.jar:bin/../lib/apache-cassandra-clientutil-1.1.0.jar:bin/../lib/apache-cassandra-thrift-1.1.0.jar:bin/../lib/avro-1.4.0-fixes.jar:bin/../lib/avro-1.4.0-sources-fixes.jar:bin/../lib/commons-cli-1.1.jar:bin/../lib/commons-codec-1.2.jar:bin/../lib/commons-lang-2.4.jar:bin/../lib/compress-lzf-0.8.4.jar:bin/../lib/concurrentlinkedhashmap-lru-1.2.jar:bin/../lib/guava-r08.jar:bin/../lib/high-scale-lib-1.1.2.jar:bin/../lib/jackson-core-asl-1.9.2.jar:bin/../lib/jackson-mapper-asl-1.9.2.jar:bin/../lib/jamm-0.2.5.jar:bin/../lib/jline-0.9.94.jar:bin/../lib/json-simple-1.1.jar:bin/../lib/libthrift-0.7.0.jar:bin/../lib/log4j-1.2.16.jar:bin/../lib/metrics-core-2.0.3.jar:bin/../lib/mx4j-tools-3.0.1.jar:bin/../lib/servlet-api-2.5-20081211.jar:bin/../lib/slf4j-api-1.6.1.jar:bin/../lib/slf4j-log4j12-1.6.1.jar:bin/../lib/snakeyaml-1.6.jar:bin/../lib/snappy-java-1.0.4.1.jar:bin/../lib/snaptree-0.1.jar:bin/../lib/jamm-0.2.5.jar INFO 15:38:01,768 JNA not found. Native methods will be disabled. INFO 15:38:01,826 Loading settings from file:/Users/walmart/Downloads/Cassandra/Node2-Cassandra1.1.0/conf ERROR 15:38:01,873 Fatal configuration error error Can't construct a java object for tag:yaml.org,2002:org.apache.cassandra.config.Config; exception=No single argument constructor found for class org.apache.cassandra.config.Config in reader, line 1, column 1: cassandra.yaml The other option would be to modify cassandra.in.sh. Has anyone tried this?? Regards, Roshni This email and any files transmitted with it are confidential and intended solely for the individual or entity to whom they are addressed. If you have received this email in error destroy it immediately. *** Walmart Confidential ***
Re: cqlsh commands
What do you mean when you say you can't display the related documentations using the help command? What does cqlsh do instead? I don't know about any bugs in that area. p On Wed, Jun 20, 2012 at 6:47 AM, Thierry Templier thierry.templ...@restlet.com wrote: Hello, I'm using cqlsh tool to create column families and it works fine. However I don't know how to use the following commands: Documented commands (type help topic): ==**== ASSUME CAPTURE DESC DESCRIBE EXIT HELP SELECT SHOW SOURCE USE Moreover I can't display the related documentations using the help command. Thanks very much for your help. Thierry
Strange behavior ¿data corruption?
Hi I'm using version 1.1.1. I'm sorry about the lack of information, i don't have stacktraces, nothig crash, just return empty, i explain, i do login as usual, find in db if there is a user named X and who belongs to client Y, if that is true i return the hash of password from db and do my checks. Sometimes, after a reboot, the login stops work, debug say cassandra is returning empty, can't find the same user named X who belongs to client Y, i take a look into db with cassandra-cli and data is there and looks fine but cassandra can't find it. I drop user columfamily and then i create the same columnfamily and fill with same data and login works again. I talk with my buddy who have his own develop environment and same strange behavior happend sometimes, always after machine halt. We work with oracle java, i'm using debian testing and phpcassa as client. Did you see something like that before? Suggestions for debug? -- Juan Ezquerro LLanes Sofistic Team Telf: 618349107/964051479
Re: Using row cache causes slowdown and unavailable reads
2300 * 5MB / 1024 = 11GB Check the logs for GC problems. Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 20/06/2012, at 8:39 PM, Nury Redjepow wrote: Good day, I'm load testing our cassandra instance. I have a column family with 2300 rows, each being ~ 5MB. And I run same query which asks for same rows. With caching='keys_only response time is adequate. But with caching='ALL', we get four times larger response time and 40-50$ of requests don't get served, error is returned. So I'm asking if 5MB rows are too big to be using row cache? Or maybe I should do some memory tweaks? I'm using Cassand 1.1.10, JNA enabled. Sincerely, Nury.
Re: Unbalanced ring in Cassandra 0.8.4
Does cleanup only cleanup keys that no longer belong to that node. Yes. I guess it could be an artefact of the bulk load. It's not been reported previously though. Try the cleanup and see how it goes. Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 21/06/2012, at 1:34 AM, Raj N wrote: Nick, thanks for the response. Does cleanup only cleanup keys that no longer belong to that node. Just to add more color, when I bulk loaded all my data into these 6 nodes, all of them had the same amount of data. After the first nodetool repair, the first node started having more data than the rest of the cluster. And since then it has never come back down. When I run cfstats on the node, the amount of data for every column family is almost 2 times the the amount of data for other. This is true for the number of keys estimate as well. For 1 CF I see more than double the number of keys and that's the largest cf as well with 34 GB data. Thanks -Rajesh On Wed, Jun 20, 2012 at 12:32 AM, Nick Bailey n...@datastax.com wrote: No. Cleanup will scan each sstable to remove data that is no longer owned by that specific node. It won't compact the sstables together however. On Tue, Jun 19, 2012 at 11:11 PM, Raj N raj.cassan...@gmail.com wrote: But wont that also run a major compaction which is not recommended anymore. -Raj On Sun, Jun 17, 2012 at 11:58 PM, aaron morton aa...@thelastpickle.com wrote: Assuming you have been running repair, it' can't hurt. Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 17/06/2012, at 4:06 AM, Raj N wrote: Nick, do you think I should still run cleanup on the first node. -Rajesh On Fri, Jun 15, 2012 at 3:47 PM, Raj N raj.cassan...@gmail.com wrote: I did run nodetool move. But that was when I was setting up the cluster which means I didn't have any data at that time. -Raj On Fri, Jun 15, 2012 at 1:29 PM, Nick Bailey n...@datastax.com wrote: Did you start all your nodes at the correct tokens or did you balance by moving them? Moving nodes around won't delete unneeded data after the move is done. Try running 'nodetool cleanup' on all of your nodes. On Fri, Jun 15, 2012 at 12:24 PM, Raj N raj.cassan...@gmail.com wrote: Actually I am not worried about the percentage. Its the data I am concerned about. Look at the first node. It has 102.07GB data. And the other nodes have around 60 GB(one has 69, but lets ignore that one). I am not understanding why the first node has almost double the data. Thanks -Raj On Fri, Jun 15, 2012 at 11:06 AM, Nick Bailey n...@datastax.com wrote: This is just a known problem with the nodetool output and multiple DCs. Your configuration is correct. The problem with nodetool is fixed in 1.1.1 https://issues.apache.org/jira/browse/CASSANDRA-3412 On Fri, Jun 15, 2012 at 9:59 AM, Raj N raj.cassan...@gmail.com wrote: Hi experts, I have a 6 node cluster across 2 DCs(DC1:3, DC2:3). I have assigned tokens using the first strategy(adding 1) mentioned here - http://wiki.apache.org/cassandra/Operations?#Token_selection But when I run nodetool ring on my cluster, this is the result I get - Address DC Rack Status State LoadOwnsToken 113427455640312814857969558651062452225 172.17.72.91DC1 RAC13 Up Normal 102.07 GB 33.33% 0 45.10.80.144DC2 RAC5 Up Normal 59.1 GB 0.00% 1 172.17.72.93DC1 RAC18 Up Normal 59.57 GB33.33% 56713727820156407428984779325531226112 45.10.80.146DC2 RAC7 Up Normal 59.64 GB0.00% 56713727820156407428984779325531226113 172.17.72.95DC1 RAC19 Up Normal 69.58 GB33.33% 113427455640312814857969558651062452224 45.10.80.148DC2 RAC9 Up Normal 59.31 GB0.00% 113427455640312814857969558651062452225 As you can see the first node has considerably more load than the others(almost double) which is surprising since all these are replicas of each other. I am running Cassandra 0.8.4. Is there an explanation for this behaviour? Could https://issues.apache.org/jira/browse/CASSANDRA-2433 be the cause for this? Thanks -Raj
RE: Much more native memory used by Cassandra then the configured JVM heap size
Just to close this item: with CASSANDRA-4314 applied I see no memory errors (either Java heap or native heap). Cassandra appears to be a hog with its memory mapped files. This caused us to wrongly think it was the culprit in a severe native memory leak. However, our leaky process was a different jsvc process altogether. I wanted to make sure I set the record straight and not leave the idea out there that Cassandra may have a memory problem. Wade Poziombka Intel Americas, Inc. From: Poziombka, Wade L [mailto:wade.l.poziom...@intel.com] Sent: Wednesday, June 13, 2012 10:53 AM To: user@cassandra.apache.org Subject: RE: Much more native memory used by Cassandra then the configured JVM heap size Seems like my only recourse is to remove jna.jar and just take the performance/swapping pain? Obviously can't have the entire box lock up. I can provide a pmap etc. if needed. From: Poziombka, Wade L [mailto:wade.l.poziom...@intel.com] Sent: Wednesday, June 13, 2012 10:28 AM To: user@cassandra.apache.orgmailto:user@cassandra.apache.org Subject: RE: Much more native memory used by Cassandra then the configured JVM heap size I have experienced the same issue. The Java heap seems fine but eventually the OS runs out of heap. In my case it renders the entire box unusable without a hard reboot. Console shows: is there a way to limit the native heap usage? xfs invoked oom-killer: gfp_mask=0x201d2, order=0, oomkilladj=0 Call Trace: [800c9d3a] out_of_memory+0x8e/0x2f3 [8002dfd7] __wake_up+0x38/0x4f [8000f677] __alloc_pages+0x27f/0x308 [80013034] __do_page_cache_readahead+0x96/0x17b [80013971] filemap_nopage+0x14c/0x360 [8000896c] __handle_mm_fault+0x1fd/0x103b [8002dfd7] __wake_up+0x38/0x4f [800671f2] do_page_fault+0x499/0x842 [800b8f39] audit_filter_syscall+0x87/0xad [8005dde9] error_exit+0x0/0x84 Node 0 DMA per-cpu: empty Node 0 DMA32 per-cpu: empty Node 0 Normal per-cpu: cpu 0 hot: high 186, batch 31 used:23 cpu 0 cold: high 62, batch 15 used:14 ... cpu 23 cold: high 62, batch 15 used:8 Node 1 HighMem per-cpu: empty Free pages: 158332kB (0kB HighMem) Active:16225503 inactive:1 dirty:0 writeback:0 unstable:0 free:39583 slab:21496 Node 0 DMA free:0kB min:0kB low:0kB high:0kB active:0kB inactive:0kB present:0kB lowmem_reserve[]: 0 0 32320 32320 Node 0 DMA32 free:0kB min:0kB low:0kB high:0kB active:0kB inactive:0kB present:0 lowmem_reserve[]: 0 0 32320 32320 Node 0 Normal free:16136kB min:16272kB low:20340kB high:24408kB active:3255624 From: aaron morton [mailto:aa...@thelastpickle.com] Sent: Tuesday, June 12, 2012 4:08 AM To: user@cassandra.apache.orgmailto:user@cassandra.apache.org Subject: Re: Much more native memory used by Cassandra then the configured JVM heap size see http://wiki.apache.org/cassandra/FAQ#mmap which cause the OS low memory. If the memory is used for mmapped access the os can get it back later. Is the low free memory causing a problem ? Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 12/06/2012, at 5:52 PM, Jason Tang wrote: Hi I found some information of this issue And seems we can have other strategy for data access to reduce mmap usage, in order to use less memory. But I didn't find the document to describe the parameters for Cassandra 1.x, is it a good way to use this parameter to reduce shared memory usage and what's the impact? (btw, our data model is dynamical, which means the although the through put is high, but the life cycle of the data is short, one hour or less). # Choices are auto, standard, mmap, and mmap_index_only. disk_access_mode: auto http://comments.gmane.org/gmane.comp.db.cassandra.user/7390 2012/6/12 Jason Tang ares.t...@gmail.commailto:ares.t...@gmail.com See my post, I limit the HVM heap 6G, but actually Cassandra will use more memory which is not calculated in JVM heap. I use top to monitor total memory used by Cassandra. = -Xms6G -Xmx6G -Xmn1600M 2012/6/12 Jeffrey Kesselman jef...@gmail.commailto:jef...@gmail.com Btw. I suggest you spin up JConsole as it will give you much more detai kon what your VM is actually doing. On Mon, Jun 11, 2012 at 9:14 PM, Jason Tang ares.t...@gmail.commailto:ares.t...@gmail.com wrote: Hi We have some problem with Cassandra memory usage, we configure the JVM HEAP 6G, but after runing Cassandra for several hours (insert, update, delete). The total memory used by Cassandra go up to 15G, which cause the OS low memory. So I wonder if it is normal to have so many memory used by cassandra? And how to limit the native memory used by Cassandra? === Cassandra 1.0.3, 64 bit jdk. Memory ocupied by Cassandra 15G PID USER PR NI VIRT RES SHR S %CPU %MEMTIME+ COMMAND 9567 casadm20 0 28.3g 15g 9.1g S 269 65.1 385:57.65 java
Re: Creating secondary index CQL3 cassandra 1.1.1
Ah yes that's it exactly, including the time outs/errors. I wonder why this didn't come up when I googled the error from my system logs. Thanks! Stephen On Thu, Jun 21, 2012 at 2:47 AM, Sylvain Lebresne sylv...@datastax.comwrote: On Thu, Jun 21, 2012 at 5:11 AM, Stephen Powis stephen.po...@pardot.com wrote: I have the following schema: describe columnfamily visitor_audit; CREATE TABLE visitor_audit ( visitor_id text, audit_id uuid, account_id int, audit_type int, created_at text, PRIMARY KEY (visitor_id, audit_id) ) WITH comment='' AND caching='KEYS_ONLY' AND read_repair_chance=0.10 AND gc_grace_seconds=864000 AND min_compaction_threshold=4 AND max_compaction_threshold=32 AND replicate_on_write='true' AND compaction_strategy_class='SizeTieredCompactionStrategy' AND compression_parameters:sstable_compression='SnappyCompressor'; I then created an index by executing the following: CREATE INDEX ix_accountid ON visitor_audit (account_id); When I attempt to execute: select * from visitor_audit where account_id=1; Nothing is returned even tho I have rows with account_id equal to 1. Is there anything I am missing here? You are pretty much hitting https://issues.apache.org/jira/browse/CASSANDRA-4328. In other words, secondary indexes is not yet supported on table with composite PRIMARY KEY, but we don't correctly reject the CREATE INDEX command. -- Sylvain
Indexing JSON in Cassandra
I know we had this conversation over on the dev list a while back: http://www.mail-archive.com/dev@cassandra.apache.org/msg03914.html I just wanted to let people know that we added the capability to our cassandra-indexing extension. http://brianoneill.blogspot.com/2012/06/indexing-json-in-cassandra.html Let us know if you have any trouble with it. -brian -- Brian ONeill Lead Architect, Health Market Science (http://healthmarketscience.com) mobile:215.588.6024 blog: http://weblogs.java.net/blog/boneill42/ blog: http://brianoneill.blogspot.com/
Re: Much more native memory used by Cassandra then the configured JVM heap size
We run some fairly large and busy Cassandra setups. All of them without mmap. I have yet to see a benchmark which conclusively can say mmap is better (or worse for that matter) than standard ways of doing I/O and we have done many of them last 2 years by different people, with different tools and with different HW. My only conclusion is that not using mmap is easier to monitor and debug (you actually see what memory is used by Cassandra) and is more stable overall. I highly recommend non-mmap setups Regards, Terje On 22 Jun 2012, at 05:05, Poziombka, Wade L wade.l.poziom...@intel.com wrote: Just to close this item: with CASSANDRA-4314 applied I see no memory errors (either Java heap or native heap). Cassandra appears to be a hog with its memory mapped files. This caused us to wrongly think it was the culprit in a severe native memory leak. However, our leaky process was a different jsvc process altogether. I wanted to make sure I set the record straight and not leave the idea out there that Cassandra may have a memory problem. Wade Poziombka Intel Americas, Inc. From: Poziombka, Wade L [mailto:wade.l.poziom...@intel.com] Sent: Wednesday, June 13, 2012 10:53 AM To: user@cassandra.apache.org Subject: RE: Much more native memory used by Cassandra then the configured JVM heap size Seems like my only recourse is to remove jna.jar and just take the performance/swapping pain? Obviously can’t have the entire box lock up. I can provide a pmap etc. if needed. From: Poziombka, Wade L [mailto:wade.l.poziom...@intel.com] Sent: Wednesday, June 13, 2012 10:28 AM To: user@cassandra.apache.org Subject: RE: Much more native memory used by Cassandra then the configured JVM heap size I have experienced the same issue. The Java heap seems fine but eventually the OS runs out of heap. In my case it renders the entire box unusable without a hard reboot. Console shows: is there a way to limit the native heap usage? xfs invoked oom-killer: gfp_mask=0x201d2, order=0, oomkilladj=0 Call Trace: [800c9d3a] out_of_memory+0x8e/0x2f3 [8002dfd7] __wake_up+0x38/0x4f [8000f677] __alloc_pages+0x27f/0x308 [80013034] __do_page_cache_readahead+0x96/0x17b [80013971] filemap_nopage+0x14c/0x360 [8000896c] __handle_mm_fault+0x1fd/0x103b [8002dfd7] __wake_up+0x38/0x4f [800671f2] do_page_fault+0x499/0x842 [800b8f39] audit_filter_syscall+0x87/0xad [8005dde9] error_exit+0x0/0x84 Node 0 DMA per-cpu: empty Node 0 DMA32 per-cpu: empty Node 0 Normal per-cpu: cpu 0 hot: high 186, batch 31 used:23 cpu 0 cold: high 62, batch 15 used:14 … cpu 23 cold: high 62, batch 15 used:8 Node 1 HighMem per-cpu: empty Free pages: 158332kB (0kB HighMem) Active:16225503 inactive:1 dirty:0 writeback:0 unstable:0 free:39583 slab:21496 Node 0 DMA free:0kB min:0kB low:0kB high:0kB active:0kB inactive:0kB present:0kB lowmem_reserve[]: 0 0 32320 32320 Node 0 DMA32 free:0kB min:0kB low:0kB high:0kB active:0kB inactive:0kB present:0 lowmem_reserve[]: 0 0 32320 32320 Node 0 Normal free:16136kB min:16272kB low:20340kB high:24408kB active:3255624 From: aaron morton [mailto:aa...@thelastpickle.com] Sent: Tuesday, June 12, 2012 4:08 AM To: user@cassandra.apache.org Subject: Re: Much more native memory used by Cassandra then the configured JVM heap size see http://wiki.apache.org/cassandra/FAQ#mmap which cause the OS low memory. If the memory is used for mmapped access the os can get it back later. Is the low free memory causing a problem ? Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 12/06/2012, at 5:52 PM, Jason Tang wrote: Hi I found some information of this issue And seems we can have other strategy for data access to reduce mmap usage, in order to use less memory. But I didn't find the document to describe the parameters for Cassandra 1.x, is it a good way to use this parameter to reduce shared memory usage and what's the impact? (btw, our data model is dynamical, which means the although the through put is high, but the life cycle of the data is short, one hour or less). # Choices are auto, standard, mmap, and mmap_index_only. disk_access_mode: auto http://comments.gmane.org/gmane.comp.db.cassandra.user/7390 2012/6/12 Jason Tang ares.t...@gmail.com See my post, I limit the HVM heap 6G, but actually Cassandra will use more memory which is not calculated in JVM heap. I use top to monitor total memory used by Cassandra. = -Xms6G -Xmx6G -Xmn1600M 2012/6/12 Jeffrey Kesselman jef...@gmail.com Btw. I suggest you spin up JConsole as it will give you much more detai kon what your VM is actually doing. On Mon, Jun 11, 2012 at 9:14 PM, Jason Tang ares.t...@gmail.com wrote: Hi
Cassandra 1.0.6 data flush query
Hi I am using Cassandra 1.0.6 version in our production system and noticed that Cassandra flushing the data to SSTable and the file size is 10MB. With under moderate write load, the Cassandra flushing lots of memtables with small sizes. With this compaction doing lots of compactions. O/S - Centos 64bit Sun Java 1.6_31 VM size - 2.4GB Following parameters change on cassandra.yaml file. flush_largest_memtables_at: 0.45 (reduce it from .75) reduce_cache_sizes_at: 0.55 (reduce it from .85) reduce_cache_capacity_to: 0.3 (reduce it from .6) concurrent_compactors: 1 memtable_total_space_in_mb: 200 in_memory_compaction_limit_in_mb: 16 (from 64MB) Key cache = 1 Row cache = 0 Could someone please help me on this. Thanks /Roshan -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Cassandra-1-0-6-data-flush-query-tp7580733.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
