Re: Memory Usage of a connection

2012-08-30 Thread rohit bhatia
PS: everything above is in bytes, not bits. On Fri, Aug 31, 2012 at 11:03 AM, rohit bhatia rohit2...@gmail.com wrote: I was wondering how much would be the memory usage of an established connection in cassandra's heap space. We are noticing extremely frequent young generation garbage

Re: Memory Usage of a connection

2012-08-31 Thread rohit bhatia
On Fri, Aug 31, 2012 at 11:27 AM, Peter Schuller peter.schul...@infidyne.com wrote: Could these 500 connections/second cause (on average) 2600Mb memory usage per 2 second ~ 1300Mb/second. or For 1 connection around 2-3Mb. In terms of garbage generated it's much less about number of

Re: Cassandra 1.1.1 on Java 7

2012-09-09 Thread rohit bhatia
@dong, any reason to do so?? On Sun, Sep 9, 2012 at 4:43 PM, dong.yajun dongt...@gmail.com wrote: ruuning for a while, you should set the -Xss to more than 160k when you using jdk1.7. On Sun, Sep 9, 2012 at 3:39 AM, Peter Schuller peter.schul...@infidyne.com wrote: Has anyone tried

Re: are counters stable enough for production?

2012-09-18 Thread rohit bhatia
We use counters in a 8 node cluster with RF 2 in cassandra 1.0.5. We use phpcassa and execute cql queries through thrift to work with composite types. We do not have any problem of overcounts as we tally with RDBMS daily. It works fine but we are having some GC pressure for young generation. Per

Re: are counters stable enough for production?

2012-09-18 Thread rohit bhatia
that the information remains the property of the sender. You must not use, disclose, distribute, copy, print or rely on this e-mail. If you have received this message in error, please contact the sender immediately and irrevocably delete this message and any copies. 2012/9/18 rohit bhatia rohit2

Re: Cassandra Counters

2012-09-25 Thread rohit bhatia
@Edward, We use counters in production with Cassandra 1.0.5. Though since our application is sensitive to write latency and we are seeing problems with Frequent Young Garbage Collections, and also we just do increments (decrements have caused problems for some people) We don't see inconsistencies

Re: Cassandra Counters

2012-09-25 Thread rohit bhatia
@Sylvain In a relatively untroubled cluster, even timed out writes go through, provided no messages are dropped. Which you can monitor on cassandra nodes. We have 100% consistency on our production servers as we don't see messages being dropped on our servers. Though as you mention, there would

Re: Persistent connection among nodes to communicate and redirect request

2012-10-02 Thread rohit bhatia
i guess 7000 is only for gossip protocol. Cassandra still uses 9160 for RPC even among nodes Also, I see Connections over port 9160 among various cassandra Nodes in my cluster. Please correct me if i am wrong.. PS: mentioned Here http://wiki.apache.org/cassandra/CloudConfig On Tue, Oct 2,

Re: Astyanax empty column check

2012-10-17 Thread rohit bhatia
See If you attempt to retrieve an entire row and it returns a result with no columns, it effectively means that row does not exist. Essentially a row without columns doesn't exist.. (except those with tombstones) from here

Re: Row cache and counters

2012-12-29 Thread rohit bhatia
Reads during a write still occur during a counter increment with CL ONE, but that latency is not counted in the request latency for the write. Your local node write latency of 45 microseconds is pretty quick. what is your timeout and the write request latency you see. In our deployment we had some

Re: Row cache and counters

2012-12-29 Thread rohit bhatia
be the reason for a 8 second timeout. On Sat, Dec 29, 2012 at 11:37 PM, André Cruz andre.c...@co.sapo.pt wrote: On 29/12/2012, at 16:59, rohit bhatia rohit2...@gmail.com wrote: Reads during a write still occur during a counter increment with CL ONE, but that latency is not counted

MeteredFlusher in system.log entries

2012-06-05 Thread rohit bhatia
MeteredFlusher use to trigger memtable flushes. Also how accurate is the estimated size in the above logfile entry. Regards Rohit Bhatia Software Engineer, Media.net

Re: MeteredFlusher in system.log entries

2012-06-05 Thread rohit bhatia
...@thelastpickle.com wrote: See the section on memtable_total_space_in_mb here  http://thelastpickle.com/2011/05/04/How-are-Memtables-measured/ Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 6/06/2012, at 2:27 AM, rohit bhatia wrote: I am trying

Re: MeteredFlusher in system.log entries

2012-06-06 Thread rohit bhatia
in memory the JVM at once.. So it implies that for flushing, Cassandra copies the memtables content. So does this imply that writes to column families are not stopped even when it is being flushed? Thanks Rohit On Wed, Jun 6, 2012 at 9:42 AM, rohit bhatia rohit2...@gmail.com wrote: Hi Aaron

Re: MeteredFlusher in system.log entries

2012-06-06 Thread rohit bhatia
no secondary indexes. The CF will not be allowed to get above one seventh of 100MB or 14MB, as if the CF filled the flush pipeline with 7 memtables of this size it would take 98MB. On Wed, Jun 6, 2012 at 6:22 PM, rohit bhatia rohit2...@gmail.com wrote: Hi.. the link http://thelastpickle.com/2011/05/04

Re: Cassandra 1 node crashed in ring

2012-06-07 Thread rohit bhatia
Restart cassandra on new node with autobootstrap as true, seed node as the existing node in the cluster and an appropriate token... You should not need to run nodetool repair as autobootstrap would take care of it. On Thu, Jun 7, 2012 at 12:22 PM, Adeel Akbar adeel.ak...@panasiangroup.com wrote:

Re: Cassandra 1 node crashed in ring

2012-06-07 Thread rohit bhatia
    16          100         Up     Normal  15.21 KB 61.52%  147906224866113468886003862620136792702 Thanks Regards Adeel Akbar -Original Message- From: rohit bhatia [mailto:rohit2...@gmail.com] Sent: Thursday, June 07, 2012 12:28 PM To: user@cassandra.apache.org Subject: Re

Re: Cassandra 1 node crashed in ring

2012-06-07 Thread rohit bhatia
for 0.8 http://www.datastax.com/docs/0.8/operations/cluster_management#replacing-a-dead-node On Thu, Jun 7, 2012 at 1:22 PM, rohit bhatia rohit2...@gmail.com wrote: pardon me for assuming that  ur new node was the same as the failed node.. please see http://www.datastax.com/docs/1.0

memtable_flush_queue_size and memtable_flush_writers

2012-06-07 Thread rohit bhatia
Hi I can't find this in any documentation online, so just wanted to ask Do all flush writers share the same flush queue or do they maintain their separate queues.. Thanks Rohit

Re: Problem in getting data from a 2 node cluster of Cassandra

2012-06-08 Thread rohit bhatia
run nodetool -h localhost cfstats on the nodes... this gives node specific column family based data... just run this for both nodes... On Fri, Jun 8, 2012 at 12:46 PM, Prakrati Agrawal prakrati.agra...@mu-sigma.com wrote: Yes the code is the same for both 1 and 2 node cluster. It's a Hector

Re: Time taken to retrieve data from a 2 node cluster is more than 1 node cluster

2012-06-08 Thread rohit bhatia
Is ur client code calling with asyncrhynous requests?? and whats ur replication factor and read consistency level. In any case, 2 nodes might take as much time as one, but should not be slow (unless u also doubled the data)... On Fri, Jun 8, 2012 at 2:41 PM, Prakrati Agrawal

Cassandra out of Heap memory

2012-06-13 Thread rohit bhatia
Hi My cassandra node went out of heap memory with this message GCInspector.java(line 88): Heap is .9934 full. Is this expected? or should I adjust my flush_largest_memtable_at variable. Also one change I did in my cluster was add 5 Column Families which are empty Should empty ColumnFamilies

Re: Cassandra out of Heap memory

2012-06-13 Thread rohit bhatia
, On Wed, Jun 13, 2012 at 6:30 PM, rohit bhatia rohit2...@gmail.com wrote: Hi My cassandra node went out of heap memory with this message GCInspector.java(line 88): Heap is .9934 full. Is this expected? or should I adjust my flush_largest_memtable_at variable. Also one change I did in my cluster

Re: Cassandra out of Heap memory

2012-06-14 Thread rohit bhatia
Looking at http://blog.mikiobraun.de/2010/08/cassandra-gc-tuning.html and server logs, I think my situation is this The default cassandra settings has the highest peak heap usage. The problem with this is that it raises the possibility that during the CMS cycle, a collection of the young

Re: Cassandra out of Heap memory

2012-06-17 Thread rohit bhatia
with a compaction or repair operation. I would also consider experimenting on one node with 8GB / 800MB heap sizes. More is not always better. - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 14/06/2012, at 8:05 PM, rohit bhatia wrote: Looking

Interpreting system.log MeteredFlusher messages

2012-06-25 Thread rohit bhatia
Hi We have 8 cassandra 1.0.5 nodes with 16 cores and 32G ram, Heap size is 12G, memtable_total_space_in_mb is one third = 4G, There are 12 Hot CFs (write-read ratio of 10). memtable_flush_queue_size = 4 and memtable_flush_writers = 2.. I got this log-entry MeteredFlusher.java (line 74)

Re: Interpreting system.log MeteredFlusher messages

2012-06-27 Thread rohit bhatia
:41 AM, rohit bhatia wrote: Hi We have 8 cassandra 1.0.5 nodes with 16 cores and 32G ram, Heap size is 12G, memtable_total_space_in_mb is one third = 4G, There are 12 Hot CFs (write-read ratio of 10). memtable_flush_queue_size = 4 and memtable_flush_writers = 2.. I got this log-entry

Finding bottleneck of a cluster

2012-07-05 Thread rohit bhatia
Our Cassandra cluster consists of 8 nodes(16 core, 32G ram, 12G Heap, 1600Mb Young gen, cassandra1.0.5, JDK 1.7, 128 Concurrent writer threads). The replication factor is 2 with 10 column families and we service Counter incrementing write intensive tasks(CL=ONE). I am trying to figure out the

Re: Finding bottleneck of a cluster

2012-07-05 Thread rohit bhatia
... messages are caused by PrintGCApplicationStoppedTime paramater which is supposed to be logged whenever threads reach a safepoint. Is there any way I can figure out what caused the java threads to pause. Thanks Rohit On Thu, Jul 5, 2012 at 12:19 PM, rohit bhatia rohit2...@gmail.com wrote: Our

Re: Upgrade for Cassandra 0.8.4 to 1.+

2012-07-05 Thread rohit bhatia
http://cassandra.apache.org/ says 1.1.2 On Thu, Jul 5, 2012 at 7:46 PM, Raj N raj.cassan...@gmail.com wrote: Hi experts, I am planning to upgrade from 0.8.4 to 1.+. Whats the latest stable version? Thanks -Rajesh

Re: Finding bottleneck of a cluster

2012-07-05 Thread rohit bhatia
for the help. Hope that helps - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 5/07/2012, at 6:49 PM, rohit bhatia wrote: Our Cassandra cluster consists of 8 nodes(16 core, 32G ram, 12G Heap, 1600Mb Young gen, cassandra1.0.5, JDK 1.7, 128 Concurrent

Re: Finding bottleneck of a cluster

2012-07-05 Thread rohit bhatia
On Fri, Jul 6, 2012 at 9:44 AM, rohit bhatia rohit2...@gmail.com wrote: On Fri, Jul 6, 2012 at 4:47 AM, aaron morton aa...@thelastpickle.com wrote: 12G Heap, 1600Mb Young gen, Is a bit higher than the normal recommendation. 1600MB young gen can cause some extra ParNew pauses. Thanks

Re: GC freeze just after repair session

2012-07-05 Thread rohit bhatia
@ravi, u can increase young gen size, keep a high tenuring rate or increase survivor ratio.. On Fri, Jul 6, 2012 at 4:03 AM, aaron morton aa...@thelastpickle.com wrote: Ideally we would like to collect maximum garbage from ParNew itself, during compactions. What are the steps to take towards

Re: MeteredFlusher in system.log entries

2012-07-08 Thread rohit bhatia
are in the queue, 1 is being flushed. Is this correct? On Wed, Jun 6, 2012 at 9:08 PM, rohit bhatia rohit2...@gmail.com wrote: Also, Could someone please explain how the factor of 7 comes in the picture in this sentence For example if memtable_total_space_in_mb is 100MB, and memtable_flush_writers

Using a node in separate cluster without decommissioning.

2012-07-10 Thread rohit bhatia
Hi I want to take out 2 nodes from a 8 node cluster and use in another cluster, but can't afford the overhead of streaming the data and rebalance cluster. Since replication factor is 2 in first cluster, I won't lose any data. I'm planning to save my commit_log and data directories and

High RecentWriteLatencyMicro

2012-07-12 Thread rohit bhatia
Hi As I understand that writes in cassandra are directly pushed to memory and using counters with CL.ONE shouldn't take the read latency for counters in account. So Writes for incrementing counters with CL.ONE should basically be really fast. But in my 8 node cluster(16 core/32G

Re: Using a node in separate cluster without decommissioning.

2012-07-13 Thread rohit bhatia
. - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 11/07/2012, at 6:35 AM, rohit bhatia wrote: Hi I want to take out 2 nodes from a 8 node cluster and use in another cluster, but can't afford the overhead of streaming the data and rebalance cluster. Since

Re: Composite Column Expiration Behavior

2012-07-18 Thread rohit bhatia
Hi, I don't think that composite columns have parent columns. your point might be true for supercolumns .. but each composite column is probably independent.. On Wed, Jul 18, 2012 at 9:14 PM, Thomas Van de Velde thomase...@gmail.com wrote: Hi there, I am trying to understand the expiration

Re: Schema advice: (Single row or multiple row!?) How do I store millions of columns when I need to read a set of around 500 columns at a single read query using column names ?

2012-07-23 Thread rohit bhatia
You should probably try to break the one row scheme to 2*Number_of_nodes rows scheme.. This should ensure proper distribution of rows and still allow u to query from a few fixed number of rows. How u do it depends on how are u gonna choose ur 200-500 columns during reading (try having them in the