)
Java HotSpot(TM) 64-Bit Server VM (build 23.7-b01, mixed mode)
Thanks
Robert
From: Robert Wille rwi...@fold3.com
Reply-To: user@cassandra.apache.org
Date: Wednesday, January 29, 2014 at 4:06 AM
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: GC taking a long time
I read
I have a dataset which is heavy on updates. The updates are actually
performed by inserting new records and deleting the old ones the following
day. Some records might be updated (replaced) a thousand times before they
are finished.
As I watch SSTables get created and compacted on my staging
Perhaps a log structured database with immutable data files is not best suited
for this use case?
Perhaps not, but I have other data structures I¹m moving to Cassandra as
well. This is just the first. Cassandra has actually worked quite well for
this first step, in spite of it not being an
I have a table with a bunch of records that have 10,000 keys per partition
key (not sure if that¹s the right terminology). Here¹s the schema:
CREATE TABLE bdn_index_pub (
tshard VARCHAR,
pord INT,
ord INT,
hpath VARCHAR,
page BIGINT,
PRIMARY KEY (tshard, pord)
) WITH gc_grace_seconds = 0;
Yes, I¹ve experienced this as well. It looks like you¹re getting the number
of items inserted mod 64K.
From: Manoj Khangaonkar khangaon...@gmail.com
Reply-To: user@cassandra.apache.org
Date: Wednesday, January 22, 2014 at 7:17 PM
To: user@cassandra.apache.org
Subject: Any Limits on number of
I didn¹t read your question properly. Collections are limited to 64K items,
not 64K bytes per item.
From: Manoj Khangaonkar khangaon...@gmail.com
Reply-To: user@cassandra.apache.org
Date: Wednesday, January 22, 2014 at 7:17 PM
To: user@cassandra.apache.org
Subject: Any Limits on number of
No tombstones, just many copies of the same data until compaction occurs.
From: Sanjeeth Kumar sanje...@exotel.in
Reply-To: user@cassandra.apache.org
Date: Tuesday, January 21, 2014 at 8:37 PM
To: user@cassandra.apache.org
Subject: Upserting the same values multiple times
Hi,
I have a
Cassandra is a last-write wins kind of a deal. The last write is determined
by the timestamp. There are two problems with this:
1. If your clocks are not synchronized, you¹re totally screwed. Note that
the 2nd and 3rd to last operations occurred just 2 milliseconds apart. A
clock skew of 2
...@match.com
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 3:28 PM
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: RE: Read/Write consistency issue
That, or roll your own locking. Means multiple updates, but it works
reliably.
tc
From: Robert Wille
Interested in knowing more on why read-before-write is an anti-pattern. In
the next month or so, I intend to use Cassandra as a doc store. One very
common operation will be to read the document, make a change, and write it
back. These would be interactive users modifying their own documents, so
with Robert's suggestion earlier in this thread of writing each update
independently and aggregating on read.
Steve
On Fri, Jan 10, 2014 at 2:35 PM, Robert Wille rwi...@fold3.com wrote:
Actually, locking won¹t fix the problem. He¹s getting the problem on a
single thread.
I¹m pretty sure
, Jan 1, 2014 at 7:53 AM, Robert Wille rwi...@fold3.com wrote:
Also, for this application, it would be quite reasonable to set gc grace
seconds to 0 for these tables. Zombie data wouldn¹t really be a problem. The
background process that cleans up orphaned browse structures would simply
re
I had a problem in my code that produced a big IN list (several tens of
thousands). I got a timeout error, not a stack overflow. 2.0.4 with java
driver 2.0 rc3.
From: Dave Brosius dbros...@mebigfatguy.com
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 5:53 PM
To:
I¹d like to have my keyspaces on different volumes, so that some can be on
SSD and others on spinning disk. Is such a thing possible or advisable?
On Jan 7, 2014 7:30 AM, Robert Wille rwi...@fold3.com wrote:
I¹d like to have my keyspaces on different volumes, so that some can be on SSD
and others on spinning disk. Is such a thing possible or advisable?
I¹ve seen a number of people on this forum that have run into a variety of
issues when creating a lot of tombstones. This makes me concerned about an
application that I¹m writing. It works great on my test server, but I¹m
concerned about what will happen when I move my production server to it. I¹m
I¹d like to attend a conference or some form of training to become more
proficient and knowledgable about Cassandra. Any suggestions?
I use hand-rolled batches a lot. You can get a *lot* of performance
improvement. Just make sure to sanitize your strings.
I¹ve been wondering, what¹s the limit, practical or hard, on the length of
a query?
Robert
On 12/11/13, 3:37 AM, David Tinker david.tin...@gmail.com wrote:
Yes thats what I
Network latency is the reason why the batched query is fastest. One trip to
Cassandra versus 1000. If you execute the inserts in parallel, then that
eliminates the latency issue.
From: Sylvain Lebresne sylv...@datastax.com
Reply-To: user@cassandra.apache.org
Date: Wednesday, December 11, 2013
...@datastax.com
Reply-To: user@cassandra.apache.org
Date: Wednesday, December 11, 2013 at 6:52 AM
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: Re: What is the fastest way to get data into Cassandra 2 from a
Java application?
On Wed, Dec 11, 2013 at 1:52 PM, Robert Wille rwi
I have a question about this statement:
When rows get above a few 10¹s of MB things can slow down, when they get
above 50 MB they can be a pain, when they get above 100MB it¹s a warning
sign. And when they get above 1GB, well you you don¹t want to know what
happens then.
I tested a data model
I recently created a test database with about 400 million small records. The
disk space consumed was about 30 GB, or 75 bytes per record.
From: onlinespending onlinespend...@gmail.com
Reply-To: user@cassandra.apache.org
Date: Monday, November 25, 2013 at 2:18 PM
To: user@cassandra.apache.org
I¹m trying to estimate our disk space requirements and I¹m wondering about
disk space required for compaction.
My application mostly inserts new data and performs updates to existing data
very infrequently, so there will be very few bytes removed by compaction. It
seems that if a major compaction
I've got a Cassandra 2.0.2 server with a single node. I've written a test
harness that populates the database, looks at the write times for each
column, runs the test cases, and then checks to see what columns have been
updated. However, when I query WRITETIME() (prior to running the test
cases),
http://www.thelastpickle.com
On 21/11/2013, at 7:45 am, Robert Wille rwi...@fold3.com wrote:
I've got a single node with all empty tables, and truncate fails with the
following error: Unable to complete request: one or more nodes were
unavailable.
Everything else seems fine. I can insert
@cassandra.apache.org user@cassandra.apache.org
Subject: RE: Intermittent connection error
Hi,
Please attach the source to have deeper look at it.
Ferenc
From: Robert Wille [mailto:rwi...@fold3.com]
Sent: Thursday, November 21, 2013 7:11 PM
To: user@cassandra.apache.org
Subject: Intermittent connection
I intermittently get the following error when I try to execute my first
query after connecting:
Caused by: com.datastax.driver.core.exceptions.NoHostAvailableException: All
host(s) tried for query failed (no host was tried)
at
I've got a single node with all empty tables, and truncate fails with the
following error: Unable to complete request: one or more nodes were
unavailable.
Everything else seems fine. I can insert, update, delete, etc.
The only thing in the logs that looks relevant is this:
INFO
I've seen the same thing
From: Sylvain Lebresne sylv...@datastax.com
Reply-To: user@cassandra.apache.org
Date: Tue, 2 Jul 2013 08:32:06 +0200
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: Re: very inefficient operation with tombstones
This is
I unsubscribed a while ago and then resubscribed. It took about four
unsubscribe attempts before it actually worked.
From: Fatih P. fatihpirist...@gmail.com
Reply-To: user@cassandra.apache.org
Date: Mon, 10 Jun 2013 17:46:30 +0300
To: user@cassandra.apache.org
Subject: Re: Unsubscribe?
i
/12/13 3:41 AM, Oleg Dulin oleg.du...@gmail.com wrote:
On 2013-05-11 14:42:32 +, Robert Wille said:
I'm using the JDBC driver to access Cassandra. I'm wondering if its
possible to iterate through a large number of records (e.g. to perform
maintenance on a large column family). I tried
I designed a data model for my data that uses a list of UUID's in a
column. When I designed my data model, my expectation was that most of the
lists would have fewer than a hundred elements, with a few having several
thousand. I discovered in my data a list that has nearly 400,000 items in
it.
I'm using the JDBC driver to access Cassandra. I'm wondering if its
possible to iterate through a large number of records (e.g. to perform
maintenance on a large column family). I tried calling
Connection.createStatement(ResultSet.TYPE_FORWARD_ONLY,
ResultSet.CONCUR_READ_ONLY), but it times out,
Just downloaded the latest Cassandra and JDBC driver. When I try to insert
UUID's into a column family, I get an exception.
Here's how I created the column family:
CREATE TABLE browse.tree (tree_id UUID PRIMARY KEY, activation_time
TIMESTAMP, tree_lock_id INT, sql_publication_id INT);
Here's
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