Re: Truncate introspection
Does drop work in a similar way? When I drop a CF and add it back with a different schema, it seems to work. But I notice that in between the drop and adding it back, when the CLI tells me the CF doesn't exist, the old data is still there. I've been assuming that this works, but just wanted to make sure... On Tue, Jun 28, 2011 at 12:56 AM, Jonathan Ellis jbel...@gmail.com wrote: Each node (independently) has logic that guarantees that any writes processed before the truncate, will be wiped out. This does not mean that each node will wipe out the same data, or even that each node will process the truncate (which would result in a timedoutexception). It also does not mean you can't have writes immediately after the truncate that would race w/ a truncate, check for zero sstables procedure. On Mon, Jun 27, 2011 at 3:35 PM, Ethan Rowe et...@the-rowes.com wrote: If those went to zero, it would certainly tell me something happened. :) I guess watching that would be a way of seeing something was going on. Is the truncate itself propagating a ring-wide marker or anything so the CF is logically empty before being physically removed? That's the impression I got from the docs but it wasn't totally clear to me. On Mon, Jun 27, 2011 at 3:33 PM, Jonathan Ellis jbel...@gmail.com wrote: There's a JMX method to get the number of sstables in a CF, is that what you're looking for? On Mon, Jun 27, 2011 at 1:04 PM, Ethan Rowe et...@the-rowes.com wrote: Is there any straightforward means of seeing what's going on after issuing a truncate (on 0.7.5)? I'm not seeing evidence that anything actually happened. I've disabled read repair on the column family in question and don't have anything actively reading/writing at present, apart from my one-off tests to see if rows have disappeared. Thanks in advance. -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Truncate introspection
Drop CF takes a snapshot of the CF first, and then marks SSTables on disk as compacted so they will be safely deleted later. Finally it removes the CF from the meta data. If you see the SSTables on disk, you should see 0 length .compacted files for every one of them. Cheers - Aaron Morton Freelance Cassandra Developer @aaronmorton http://www.thelastpickle.com On 28 Jun 2011, at 20:00, David Boxenhorn wrote: Does drop work in a similar way? When I drop a CF and add it back with a different schema, it seems to work. But I notice that in between the drop and adding it back, when the CLI tells me the CF doesn't exist, the old data is still there. I've been assuming that this works, but just wanted to make sure... On Tue, Jun 28, 2011 at 12:56 AM, Jonathan Ellis jbel...@gmail.com wrote: Each node (independently) has logic that guarantees that any writes processed before the truncate, will be wiped out. This does not mean that each node will wipe out the same data, or even that each node will process the truncate (which would result in a timedoutexception). It also does not mean you can't have writes immediately after the truncate that would race w/ a truncate, check for zero sstables procedure. On Mon, Jun 27, 2011 at 3:35 PM, Ethan Rowe et...@the-rowes.com wrote: If those went to zero, it would certainly tell me something happened. :) I guess watching that would be a way of seeing something was going on. Is the truncate itself propagating a ring-wide marker or anything so the CF is logically empty before being physically removed? That's the impression I got from the docs but it wasn't totally clear to me. On Mon, Jun 27, 2011 at 3:33 PM, Jonathan Ellis jbel...@gmail.com wrote: There's a JMX method to get the number of sstables in a CF, is that what you're looking for? On Mon, Jun 27, 2011 at 1:04 PM, Ethan Rowe et...@the-rowes.com wrote: Is there any straightforward means of seeing what's going on after issuing a truncate (on 0.7.5)? I'm not seeing evidence that anything actually happened. I've disabled read repair on the column family in question and don't have anything actively reading/writing at present, apart from my one-off tests to see if rows have disappeared. Thanks in advance. -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Truncate introspection
Is there any straightforward means of seeing what's going on after issuing a truncate (on 0.7.5)? I'm not seeing evidence that anything actually happened. I've disabled read repair on the column family in question and don't have anything actively reading/writing at present, apart from my one-off tests to see if rows have disappeared. Thanks in advance.
Re: Truncate introspection
There's a JMX method to get the number of sstables in a CF, is that what you're looking for? On Mon, Jun 27, 2011 at 1:04 PM, Ethan Rowe et...@the-rowes.com wrote: Is there any straightforward means of seeing what's going on after issuing a truncate (on 0.7.5)? I'm not seeing evidence that anything actually happened. I've disabled read repair on the column family in question and don't have anything actively reading/writing at present, apart from my one-off tests to see if rows have disappeared. Thanks in advance. -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Truncate introspection
If those went to zero, it would certainly tell me something happened. :) I guess watching that would be a way of seeing something was going on. Is the truncate itself propagating a ring-wide marker or anything so the CF is logically empty before being physically removed? That's the impression I got from the docs but it wasn't totally clear to me. On Mon, Jun 27, 2011 at 3:33 PM, Jonathan Ellis jbel...@gmail.com wrote: There's a JMX method to get the number of sstables in a CF, is that what you're looking for? On Mon, Jun 27, 2011 at 1:04 PM, Ethan Rowe et...@the-rowes.com wrote: Is there any straightforward means of seeing what's going on after issuing a truncate (on 0.7.5)? I'm not seeing evidence that anything actually happened. I've disabled read repair on the column family in question and don't have anything actively reading/writing at present, apart from my one-off tests to see if rows have disappeared. Thanks in advance. -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Truncate introspection
Each node (independently) has logic that guarantees that any writes processed before the truncate, will be wiped out. This does not mean that each node will wipe out the same data, or even that each node will process the truncate (which would result in a timedoutexception). It also does not mean you can't have writes immediately after the truncate that would race w/ a truncate, check for zero sstables procedure. On Mon, Jun 27, 2011 at 3:35 PM, Ethan Rowe et...@the-rowes.com wrote: If those went to zero, it would certainly tell me something happened. :) I guess watching that would be a way of seeing something was going on. Is the truncate itself propagating a ring-wide marker or anything so the CF is logically empty before being physically removed? That's the impression I got from the docs but it wasn't totally clear to me. On Mon, Jun 27, 2011 at 3:33 PM, Jonathan Ellis jbel...@gmail.com wrote: There's a JMX method to get the number of sstables in a CF, is that what you're looking for? On Mon, Jun 27, 2011 at 1:04 PM, Ethan Rowe et...@the-rowes.com wrote: Is there any straightforward means of seeing what's going on after issuing a truncate (on 0.7.5)? I'm not seeing evidence that anything actually happened. I've disabled read repair on the column family in question and don't have anything actively reading/writing at present, apart from my one-off tests to see if rows have disappeared. Thanks in advance. -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
