Re: snapshot files locked
Hi Maki,
Thanks for the reply. Yes, I understand that snapshots are hard links.
However, my understanding is that removing any hard-linked files just
removes the link (decrementing the link counter of the file on disk) --
it does not delete the file itself nor remove any other links which may
be pointing at the file. To confirm my understanding, I tested this in
Windows by terminating Cassandra and then deleting all files in the
snapshot dir. None of the corresponding files in the parent keyspace
directory were removed.
Regards,
Jim
On 3/13/2012 9:29 PM, Maki Watanabe wrote:
snapshot files are hardlinks of the original sstables.
As you know, on windows, you can't delete files opened by other process.
If you try to delete the hardlink, windows thinks you try to delete
the sstables in production.
maki
2012/3/14 Jim Newshamjnews...@referentia.com:
Hi,
I'm using Cassandra 1.0.8, on Windows 7. When I take a snapshot of the
database, I find that I am unable to delete the snapshot directory (i.e.,
dir named {datadir}\{keyspacename}\snapshots\{snapshottag}) while
Cassandra is running: The action can't be completed because the folder or
a file in it is open in another program. Close the folder or file and try
again. If I terminate Cassandra, then I can delete the directory with no
problem. Is there a reason why Cassandra must hold onto these files?
Thanks,
Jim
snapshot files locked
Hi,
I'm using Cassandra 1.0.8, on Windows 7. When I take a snapshot of the
database, I find that I am unable to delete the snapshot directory
(i.e., dir named {datadir}\{keyspacename}\snapshots\{snapshottag})
while Cassandra is running: The action can't be completed because the
folder or a file in it is open in another program. Close the folder or
file and try again. If I terminate Cassandra, then I can delete the
directory with no problem. Is there a reason why Cassandra must hold
onto these files?
Thanks,
Jim
Re: how stable is 1.0 these days?
Could you also elaborate for creating/dropping column families? We're currently working on moving to 1.0 and using dynamically created tables, so I'm very interested in what issues we might encounter. So far the only thing I've encountered (with 1.0.7 + hector 1.0-2) is that dropping a cf may sometimes fail with UnavailableException. I think this happens when the cf is busy being compacted. When I sleep/retry within a loop it eventually succeeds. Thanks, Jim On 1/26/2012 7:32 AM, Pierre-Yves Ritschard wrote: Can you elaborate on the composite types instabilities ? is this specific to hector as the radim's posts suggests ? These one liner answers are quite stressful :) On Thu, Jan 26, 2012 at 1:28 PM, Carlo Pirescarlopi...@gmail.com wrote: If you need to use composite types and create/drop column families on the fly you must be prepared to instabilities.
Re: rename column family
Thanks that's very helpful. I'm assuming there's no requirement to stop or restart Cassandra? Thanks, Jim On 1/2/2012 12:07 AM, aaron morton wrote: Renaming a CF is not directly supported. You can: 1) Add the new CF using the CLI or CQL 2) On each node copy the SSTable files and use the new CF name. 3) Drop the old CF using the CLI or CQL 4) The Drop CF command will create a snapshot, you may want to delete this. Hope that helps. - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 31/12/2011, at 8:42 AM, Jim Newsham wrote: How can I rename a column family (if version matters, I'm interested in both 0.8.x and 1.0.x). Thanks, Jim
rename column family
How can I rename a column family (if version matters, I'm interested in both 0.8.x and 1.0.x). Thanks, Jim
Re: Second Cassandra users survey
- Bulk column deletion by (column name) range. Without this feature, we are forced to perform a range query and iterate over all of the columns, deleting them one by one (we do this in a batch, but it's still a very slow approach). See CASSANDRA-494/3448. If anyone else has a need for this issue, please raise your voice, as the feature has been tabled due to lack of interest. On 11/3/2011 11:44 AM, Todd Burruss wrote: - Better performance when access random columns in a wide row - caching subsets of wide rows - possibly on the same boundaries as the index - some sort of notification architecture when data is inserted. This could be co-processors, triggers, plugins, etc - auto load balance when adding new nodes On 11/1/11 3:59 PM, Jonathan Ellisjbel...@gmail.com wrote: Hi all, Two years ago I asked for Cassandra use cases and feature requests. [1] The results [2] have been extremely useful in setting and prioritizing goals for Cassandra development. But with the release of 1.0 we've accomplished basically everything from our original wish list. [3] I'd love to hear from modern Cassandra users again, especially if you're usually a quiet lurker. What does Cassandra do well? What are your pain points? What's your feature wish list? As before, if you're in stealth mode or don't want to say anything in public, feel free to reply to me privately and I will keep it off the record. [1] http://www.mail-archive.com/cassandra-dev@incubator.apache.org/msg01148.ht ml [2] http://www.mail-archive.com/cassandra-user@incubator.apache.org/msg01446.h tml [3] http://www.mail-archive.com/dev@cassandra.apache.org/msg01524.html -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Second Cassandra users survey
On 11/4/2011 4:32 PM, Brandon Williams wrote: On Fri, Nov 4, 2011 at 9:19 PM, Jim Newshamjnews...@referentia.com wrote: - Bulk column deletion by (column name) range. Without this feature, we are forced to perform a range query and iterate over all of the columns, deleting them one by one (we do this in a batch, but it's still a very slow approach). See CASSANDRA-494/3448. If anyone else has a need for this issue, please raise your voice, as the feature has been tabled due to lack of interest. I think the lack of interest here has been this: it's unusual to want to delete columns for which you do not know the names, but also not want to delete the entire row. Is there any chance you're trying to delete the entire row, or is it truly the case I just described? -Brandon Our use case is time-series data (such as sampled sensor data). Each row describes a particular statistic over time, the column name is a time, and the column value is the sample. So it makes perfect sense to want to delete columns for a given time range. I'm sure there must be numerous other use cases for which using a range of column names makes sense. Regards, Jim
