Re: LCS not removing rows with all TTL expired columns
,1357785277207001,d], [req_finish_time_us,50f21d3d,1357785277207001,d], [req_method,50f21d3d,1357785277207001,d], [req_service,50f21d3d,1357785277207001,d], [req_start_time_us,50f21d3d,1357785277207001,d], [success,50f21d3d,1357785277207001,d]] } My experience with TTL columns so far has been pretty similar to Viktor's in that the only way to keep them row count under control is to force major compactions. In real world use, STCS and LCS both leave TTL expired rows around forever as far as I can tell. When testing with minimal data, removal of TTL expired rows seem to work as expected but in this case there seems to be some divergence from real life work and test samples. -Bryan On Thu, Jan 17, 2013 at 1:47 AM, Viktor Jevdokimov viktor.jevdoki...@adform.com wrote: @Bryan, ** ** To keep data size as low as possible with TTL columns we still use STCS and nightly major compactions. ** ** Experience with LCS was not successful in our case, data size keeps too high along with amount of compactions. ** ** IMO, before 1.2, LCS was good for CFs without TTL or high delete rate. I have not tested 1.2 LCS behavior, we’re still on 1.0.x ** ** ** ** Best regards / Pagarbiai *Viktor Jevdokimov* Senior Developer Email: viktor.jevdoki...@adform.com Phone: +370 5 212 3063, Fax +370 5 261 0453 J. Jasinskio 16C, LT-01112 Vilnius, Lithuania Follow us on Twitter: @adforminsiderhttp://twitter.com/#!/adforminsider Take a ride with Adform's Rich Media Suitehttp://vimeo.com/adform/richmedia [image: Adform News] http://www.adform.com [image: Adform awarded the Best Employer 2012] http://www.adform.com/site/blog/adform/adform-takes-top-spot-in-best-employer-survey/ Disclaimer: The information contained in this message and attachments is intended solely for the attention and use of the named addressee and may be confidential. If you are not the intended recipient, you are reminded 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. *From:* aaron morton [mailto:aa...@thelastpickle.com] *Sent:* Thursday, January 17, 2013 06:24 *To:* user@cassandra.apache.org *Subject:* Re: LCS not removing rows with all TTL expired columns ** ** Minor compaction (with Size Tiered) will only purge tombstones if all fragments of a row are contained in the SSTables being compacted. So if you have a long lived row, that is present in many size tiers, the columns will not be purged. ** ** (thus compacted compacted) 3 days after all columns for that row had expired Tombstones have to get on disk, even if you set the gc_grace_seconds to 0. If not they do not get a chance to delete previous versions of the column which already exist on disk. So when the compaction ran your ExpiringColumn was turned into a DeletedColumn and placed on disk. *** * ** ** I would expect the next round of compaction to remove these columns. * *** ** ** There is a new feature in 1.2 that may help you here. It will do a special compaction of individual sstables when they have a certain proportion of dead columns https://issues.apache.org/jira/browse/CASSANDRA-3442 ** ** Also interested to know if LCS helps. ** ** Cheers ** ** - Aaron Morton Freelance Cassandra Developer New Zealand ** ** @aaronmorton http://www.thelastpickle.com ** ** On 17/01/2013, at 2:55 PM, Bryan Talbot btal...@aeriagames.com wrote: According to the timestamps (see original post) the SSTable was written (thus compacted compacted) 3 days after all columns for that row had expired and 6 days after the row was created; yet all columns are still showing up in the SSTable. Note that the column shows now rows when a get for that key is run so that's working correctly, but the data is lugged around far longer than it should be -- maybe forever. ** ** ** ** -Bryan ** ** On Wed, Jan 16, 2013 at 5:44 PM, Andrey Ilinykh ailin...@gmail.com wrote: To get column removed you have to meet two requirements 1. column should be expired 2. after that CF gets compacted ** ** I guess your expired columns are propagated to high tier CF, which gets compacted rarely. So, you have to wait when high tier CF gets compacted. ** ** Andrey ** ** ** ** On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.com wrote: On cassandra 1.1.5 with a write heavy workload, we're having problems getting rows to be compacted away (removed) even though all columns have expired TTL. We've tried size tiered and now leveled and are seeing the same symptom: the data stays around essentially forever
Re: LCS not removing rows with all TTL expired columns
], [client_req_id,50f21d3d,1357785277207001,d], [mysql_call_cnt,50f21d3d,1357785277207001,d], [mysql_duration_us,50f21d3d,1357785277207001,d], [mysql_failure_call_cnt,50f21d3d,1357785277207001,d], [mysql_success_call_cnt,50f21d3d,1357785277207001,d], [req_duration_us,50f21d3d,1357785277207001,d], [req_finish_time_us,50f21d3d,1357785277207001,d], [req_method,50f21d3d,1357785277207001,d], [req_service,50f21d3d,1357785277207001,d], [req_start_time_us,50f21d3d,1357785277207001,d], [success,50f21d3d,1357785277207001,d]] } My experience with TTL columns so far has been pretty similar to Viktor's in that the only way to keep them row count under control is to force major compactions. In real world use, STCS and LCS both leave TTL expired rows around forever as far as I can tell. When testing with minimal data, removal of TTL expired rows seem to work as expected but in this case there seems to be some divergence from real life work and test samples. -Bryan On Thu, Jan 17, 2013 at 1:47 AM, Viktor Jevdokimov viktor.jevdoki...@adform.com wrote: @Bryan, ** ** To keep data size as low as possible with TTL columns we still use STCS and nightly major compactions. ** ** Experience with LCS was not successful in our case, data size keeps too high along with amount of compactions. ** ** IMO, before 1.2, LCS was good for CFs without TTL or high delete rate. I have not tested 1.2 LCS behavior, we’re still on 1.0.x ** ** ** ** Best regards / Pagarbiai *Viktor Jevdokimov* Senior Developer Email: viktor.jevdoki...@adform.com Phone: +370 5 212 3063, Fax +370 5 261 0453 J. Jasinskio 16C, LT-01112 Vilnius, Lithuania Follow us on Twitter: @adforminsiderhttp://twitter.com/#!/adforminsider Take a ride with Adform's Rich Media Suitehttp://vimeo.com/adform/richmedia [image: Adform News] http://www.adform.com [image: Adform awarded the Best Employer 2012] http://www.adform.com/site/blog/adform/adform-takes-top-spot-in-best-employer-survey/ Disclaimer: The information contained in this message and attachments is intended solely for the attention and use of the named addressee and may be confidential. If you are not the intended recipient, you are reminded 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. *From:* aaron morton [mailto:aa...@thelastpickle.com] *Sent:* Thursday, January 17, 2013 06:24 *To:* user@cassandra.apache.org *Subject:* Re: LCS not removing rows with all TTL expired columns ** ** Minor compaction (with Size Tiered) will only purge tombstones if all fragments of a row are contained in the SSTables being compacted. So if you have a long lived row, that is present in many size tiers, the columns will not be purged. ** ** (thus compacted compacted) 3 days after all columns for that row had expired Tombstones have to get on disk, even if you set the gc_grace_seconds to 0. If not they do not get a chance to delete previous versions of the column which already exist on disk. So when the compaction ran your ExpiringColumn was turned into a DeletedColumn and placed on disk. ** ** ** ** I would expect the next round of compaction to remove these columns. ** ** There is a new feature in 1.2 that may help you here. It will do a special compaction of individual sstables when they have a certain proportion of dead columns https://issues.apache.org/jira/browse/CASSANDRA-3442 ** ** Also interested to know if LCS helps. ** ** Cheers ** ** - Aaron Morton Freelance Cassandra Developer New Zealand ** ** @aaronmorton http://www.thelastpickle.com ** ** On 17/01/2013, at 2:55 PM, Bryan Talbot btal...@aeriagames.com wrote: According to the timestamps (see original post) the SSTable was written (thus compacted compacted) 3 days after all columns for that row had expired and 6 days after the row was created; yet all columns are still showing up in the SSTable. Note that the column shows now rows when a get for that key is run so that's working correctly, but the data is lugged around far longer than it should be -- maybe forever. ** ** ** ** -Bryan ** ** On Wed, Jan 16, 2013 at 5:44 PM, Andrey Ilinykh ailin...@gmail.com wrote: To get column removed you have to meet two requirements 1. column should be expired 2. after that CF gets compacted ** ** I guess your expired columns are propagated to high tier CF, which gets compacted rarely. So, you have to wait when high tier CF gets compacted. ** ** Andrey ** ** ** ** On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.com wrote
RE: LCS not removing rows with all TTL expired columns
@Bryan, To keep data size as low as possible with TTL columns we still use STCS and nightly major compactions. Experience with LCS was not successful in our case, data size keeps too high along with amount of compactions. IMO, before 1.2, LCS was good for CFs without TTL or high delete rate. I have not tested 1.2 LCS behavior, we're still on 1.0.x Best regards / Pagarbiai Viktor Jevdokimov Senior Developer Email: viktor.jevdoki...@adform.commailto:viktor.jevdoki...@adform.com Phone: +370 5 212 3063, Fax +370 5 261 0453 J. Jasinskio 16C, LT-01112 Vilnius, Lithuania Follow us on Twitter: @adforminsiderhttp://twitter.com/#!/adforminsider Take a ride with Adform's Rich Media Suitehttp://vimeo.com/adform/richmedia [Adform News] http://www.adform.com [Adform awarded the Best Employer 2012] http://www.adform.com/site/blog/adform/adform-takes-top-spot-in-best-employer-survey/ Disclaimer: The information contained in this message and attachments is intended solely for the attention and use of the named addressee and may be confidential. If you are not the intended recipient, you are reminded 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. From: aaron morton [mailto:aa...@thelastpickle.com] Sent: Thursday, January 17, 2013 06:24 To: user@cassandra.apache.org Subject: Re: LCS not removing rows with all TTL expired columns Minor compaction (with Size Tiered) will only purge tombstones if all fragments of a row are contained in the SSTables being compacted. So if you have a long lived row, that is present in many size tiers, the columns will not be purged. (thus compacted compacted) 3 days after all columns for that row had expired Tombstones have to get on disk, even if you set the gc_grace_seconds to 0. If not they do not get a chance to delete previous versions of the column which already exist on disk. So when the compaction ran your ExpiringColumn was turned into a DeletedColumn and placed on disk. I would expect the next round of compaction to remove these columns. There is a new feature in 1.2 that may help you here. It will do a special compaction of individual sstables when they have a certain proportion of dead columns https://issues.apache.org/jira/browse/CASSANDRA-3442 Also interested to know if LCS helps. Cheers - Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton http://www.thelastpickle.com On 17/01/2013, at 2:55 PM, Bryan Talbot btal...@aeriagames.commailto:btal...@aeriagames.com wrote: According to the timestamps (see original post) the SSTable was written (thus compacted compacted) 3 days after all columns for that row had expired and 6 days after the row was created; yet all columns are still showing up in the SSTable. Note that the column shows now rows when a get for that key is run so that's working correctly, but the data is lugged around far longer than it should be -- maybe forever. -Bryan On Wed, Jan 16, 2013 at 5:44 PM, Andrey Ilinykh ailin...@gmail.commailto:ailin...@gmail.com wrote: To get column removed you have to meet two requirements 1. column should be expired 2. after that CF gets compacted I guess your expired columns are propagated to high tier CF, which gets compacted rarely. So, you have to wait when high tier CF gets compacted. Andrey On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.commailto:btal...@aeriagames.com wrote: On cassandra 1.1.5 with a write heavy workload, we're having problems getting rows to be compacted away (removed) even though all columns have expired TTL. We've tried size tiered and now leveled and are seeing the same symptom: the data stays around essentially forever. Currently we write all columns with a TTL of 72 hours (259200 seconds) and expect to add 10 GB of data to this CF per day per node. Each node currently has 73 GB for the affected CF and shows no indications that old rows will be removed on their own. Why aren't rows being removed? Below is some data from a sample row which should have been removed several days ago but is still around even though it has been involved in numerous compactions since being expired. $ ./bin/nodetool -h localhost getsstables metrics request_summary 459fb460-5ace-11e2-9b92-11d67b6163b4 /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db $ ls -alF /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db -rw-rw-r-- 1 sandra sandra 5252320 Jan 16 08:42 /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db $ ./bin/sstable2json /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db -k $(echo -n 459fb460-5ace-11e2-9b92
Re: LCS not removing rows with all TTL expired columns
We are using LCS and the particular row I've referenced has been involved
in several compactions after all columns have TTL expired. The most recent
one was again this morning and the row is still there -- TTL expired for
several days now with gc_grace=0 and several compactions later ...
$ ./bin/nodetool -h localhost getsstables metrics request_summary
459fb460-5ace-11e2-9b92-11d67b6163b4
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-448955-Data.db
$ ls -alF
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-448955-Data.db
-rw-rw-r-- 1 sandra sandra 5246509 Jan 17 06:54
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-448955-Data.db
$ ./bin/sstable2json
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-448955-Data.db
-k $(echo -n 459fb460-5ace-11e2-9b92-11d67b6163b4 | hexdump -e '36/1 %x')
{
34353966623436302d356163652d313165322d396239322d313164363762363136336234:
[[app_name,50f21d3d,1357785277207001,d],
[client_ip,50f21d3d,1357785277207001,d],
[client_req_id,50f21d3d,1357785277207001,d],
[mysql_call_cnt,50f21d3d,1357785277207001,d],
[mysql_duration_us,50f21d3d,1357785277207001,d],
[mysql_failure_call_cnt,50f21d3d,1357785277207001,d],
[mysql_success_call_cnt,50f21d3d,1357785277207001,d],
[req_duration_us,50f21d3d,1357785277207001,d],
[req_finish_time_us,50f21d3d,1357785277207001,d],
[req_method,50f21d3d,1357785277207001,d],
[req_service,50f21d3d,1357785277207001,d],
[req_start_time_us,50f21d3d,1357785277207001,d],
[success,50f21d3d,1357785277207001,d]]
}
My experience with TTL columns so far has been pretty similar to Viktor's
in that the only way to keep them row count under control is to force major
compactions. In real world use, STCS and LCS both leave TTL expired rows
around forever as far as I can tell. When testing with minimal data,
removal of TTL expired rows seem to work as expected but in this case there
seems to be some divergence from real life work and test samples.
-Bryan
On Thu, Jan 17, 2013 at 1:47 AM, Viktor Jevdokimov
viktor.jevdoki...@adform.com wrote:
@Bryan,
** **
To keep data size as low as possible with TTL columns we still use STCS
and nightly major compactions.
** **
Experience with LCS was not successful in our case, data size keeps too
high along with amount of compactions.
** **
IMO, before 1.2, LCS was good for CFs without TTL or high delete rate. I
have not tested 1.2 LCS behavior, we’re still on 1.0.x
** **
** **
Best regards / Pagarbiai
*Viktor Jevdokimov*
Senior Developer
Email: viktor.jevdoki...@adform.com
Phone: +370 5 212 3063, Fax +370 5 261 0453
J. Jasinskio 16C, LT-01112 Vilnius, Lithuania
Follow us on Twitter: @adforminsider http://twitter.com/#!/adforminsider
Take a ride with Adform's Rich Media Suitehttp://vimeo.com/adform/richmedia
[image: Adform News] http://www.adform.com
[image: Adform awarded the Best Employer 2012]
http://www.adform.com/site/blog/adform/adform-takes-top-spot-in-best-employer-survey/
Disclaimer: The information contained in this message and attachments is
intended solely for the attention and use of the named addressee and may be
confidential. If you are not the intended recipient, you are reminded 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.
*From:* aaron morton [mailto:aa...@thelastpickle.com]
*Sent:* Thursday, January 17, 2013 06:24
*To:* user@cassandra.apache.org
*Subject:* Re: LCS not removing rows with all TTL expired columns
** **
Minor compaction (with Size Tiered) will only purge tombstones if all
fragments of a row are contained in the SSTables being compacted. So if you
have a long lived row, that is present in many size tiers, the columns will
not be purged.
** **
(thus compacted compacted) 3 days after all columns for that row had
expired
Tombstones have to get on disk, even if you set the gc_grace_seconds to 0.
If not they do not get a chance to delete previous versions of the column
which already exist on disk. So when the compaction ran your ExpiringColumn
was turned into a DeletedColumn and placed on disk.
** **
I would expect the next round of compaction to remove these columns.
** **
There is a new feature in 1.2 that may help you here. It will do a special
compaction of individual sstables when they have a certain proportion of
dead columns https://issues.apache.org/jira/browse/CASSANDRA-3442
** **
Also interested to know if LCS helps.
** **
Cheers
** **
-
Aaron Morton
Freelance Cassandra Developer
New Zealand
** **
@aaronmorton
http://www.thelastpickle.com
Re: LCS not removing rows with all TTL expired columns
/richmedia
[image: Adform News] http://www.adform.com
[image: Adform awarded the Best Employer 2012]
http://www.adform.com/site/blog/adform/adform-takes-top-spot-in-best-employer-survey/
Disclaimer: The information contained in this message and attachments is
intended solely for the attention and use of the named addressee and may be
confidential. If you are not the intended recipient, you are reminded 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.
*From:* aaron morton [mailto:aa...@thelastpickle.com]
*Sent:* Thursday, January 17, 2013 06:24
*To:* user@cassandra.apache.org
*Subject:* Re: LCS not removing rows with all TTL expired columns
** **
Minor compaction (with Size Tiered) will only purge tombstones if all
fragments of a row are contained in the SSTables being compacted. So if you
have a long lived row, that is present in many size tiers, the columns will
not be purged.
** **
(thus compacted compacted) 3 days after all columns for that row had
expired
Tombstones have to get on disk, even if you set the gc_grace_seconds to
0. If not they do not get a chance to delete previous versions of the
column which already exist on disk. So when the compaction ran your
ExpiringColumn was turned into a DeletedColumn and placed on disk.
** **
I would expect the next round of compaction to remove these columns.
** **
There is a new feature in 1.2 that may help you here. It will do a
special compaction of individual sstables when they have a certain
proportion of dead columns
https://issues.apache.org/jira/browse/CASSANDRA-3442
** **
Also interested to know if LCS helps.
** **
Cheers
** **
-
Aaron Morton
Freelance Cassandra Developer
New Zealand
** **
@aaronmorton
http://www.thelastpickle.com
** **
On 17/01/2013, at 2:55 PM, Bryan Talbot btal...@aeriagames.com wrote:**
**
According to the timestamps (see original post) the SSTable was written
(thus compacted compacted) 3 days after all columns for that row had
expired and 6 days after the row was created; yet all columns are still
showing up in the SSTable. Note that the column shows now rows when a
get for that key is run so that's working correctly, but the data is
lugged around far longer than it should be -- maybe forever.
** **
** **
-Bryan
** **
On Wed, Jan 16, 2013 at 5:44 PM, Andrey Ilinykh ailin...@gmail.com
wrote:
To get column removed you have to meet two requirements
1. column should be expired
2. after that CF gets compacted
** **
I guess your expired columns are propagated to high tier CF, which gets
compacted rarely.
So, you have to wait when high tier CF gets compacted.
** **
Andrey
** **
** **
On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.com
wrote:
On cassandra 1.1.5 with a write heavy workload, we're having problems
getting rows to be compacted away (removed) even though all columns have
expired TTL. We've tried size tiered and now leveled and are seeing the
same symptom: the data stays around essentially forever.
** **
Currently we write all columns with a TTL of 72 hours (259200 seconds)
and expect to add 10 GB of data to this CF per day per node. Each node
currently has 73 GB for the affected CF and shows no indications that old
rows will be removed on their own.
** **
Why aren't rows being removed? Below is some data from a sample row
which should have been removed several days ago but is still around even
though it has been involved in numerous compactions since being expired.*
***
** **
$ ./bin/nodetool -h localhost getsstables metrics request_summary
459fb460-5ace-11e2-9b92-11d67b6163b4
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
** **
$ ls -alF
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
-rw-rw-r-- 1 sandra sandra 5252320 Jan 16 08:42
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
** **
$ ./bin/sstable2json
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
-k $(echo -n 459fb460-5ace-11e2-9b92-11d67b6163b4 | hexdump -e '36/1 %x')
{
34353966623436302d356163652d313165322d396239322d313164363762363136336234:
[[app_name,50f21d3d,1357785277207001,d],
[client_ip,50f21d3d,1357785277207001,d],
[client_req_id,50f21d3d,1357785277207001,d],
[mysql_call_cnt,50f21d3d,1357785277207001,d],
[mysql_duration_us,50f21d3d,1357785277207001,d],
[mysql_failure_call_cnt,50f21d3d,1357785277207001,d
Re: LCS not removing rows with all TTL expired columns
Developer Email: viktor.jevdoki...@adform.com Phone: +370 5 212 3063, Fax +370 5 261 0453 J. Jasinskio 16C, LT-01112 Vilnius, Lithuania Follow us on Twitter: @adforminsiderhttp://twitter.com/#!/adforminsider Take a ride with Adform's Rich Media Suitehttp://vimeo.com/adform/richmedia [image: Adform News] http://www.adform.com [image: Adform awarded the Best Employer 2012] http://www.adform.com/site/blog/adform/adform-takes-top-spot-in-best-employer-survey/ Disclaimer: The information contained in this message and attachments is intended solely for the attention and use of the named addressee and may be confidential. If you are not the intended recipient, you are reminded 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. *From:* aaron morton [mailto:aa...@thelastpickle.com] *Sent:* Thursday, January 17, 2013 06:24 *To:* user@cassandra.apache.org *Subject:* Re: LCS not removing rows with all TTL expired columns ** ** Minor compaction (with Size Tiered) will only purge tombstones if all fragments of a row are contained in the SSTables being compacted. So if you have a long lived row, that is present in many size tiers, the columns will not be purged. ** ** (thus compacted compacted) 3 days after all columns for that row had expired Tombstones have to get on disk, even if you set the gc_grace_seconds to 0. If not they do not get a chance to delete previous versions of the column which already exist on disk. So when the compaction ran your ExpiringColumn was turned into a DeletedColumn and placed on disk. ** ** I would expect the next round of compaction to remove these columns. *** * ** ** There is a new feature in 1.2 that may help you here. It will do a special compaction of individual sstables when they have a certain proportion of dead columns https://issues.apache.org/jira/browse/CASSANDRA-3442 ** ** Also interested to know if LCS helps. ** ** Cheers ** ** - Aaron Morton Freelance Cassandra Developer New Zealand ** ** @aaronmorton http://www.thelastpickle.com ** ** On 17/01/2013, at 2:55 PM, Bryan Talbot btal...@aeriagames.com wrote:* *** According to the timestamps (see original post) the SSTable was written (thus compacted compacted) 3 days after all columns for that row had expired and 6 days after the row was created; yet all columns are still showing up in the SSTable. Note that the column shows now rows when a get for that key is run so that's working correctly, but the data is lugged around far longer than it should be -- maybe forever. ** ** ** ** -Bryan ** ** On Wed, Jan 16, 2013 at 5:44 PM, Andrey Ilinykh ailin...@gmail.com wrote: To get column removed you have to meet two requirements 1. column should be expired 2. after that CF gets compacted ** ** I guess your expired columns are propagated to high tier CF, which gets compacted rarely. So, you have to wait when high tier CF gets compacted. ** ** Andrey ** ** ** ** On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.com wrote: On cassandra 1.1.5 with a write heavy workload, we're having problems getting rows to be compacted away (removed) even though all columns have expired TTL. We've tried size tiered and now leveled and are seeing the same symptom: the data stays around essentially forever. ** ** Currently we write all columns with a TTL of 72 hours (259200 seconds) and expect to add 10 GB of data to this CF per day per node. Each node currently has 73 GB for the affected CF and shows no indications that old rows will be removed on their own. ** ** Why aren't rows being removed? Below is some data from a sample row which should have been removed several days ago but is still around even though it has been involved in numerous compactions since being expired. ** ** $ ./bin/nodetool -h localhost getsstables metrics request_summary 459fb460-5ace-11e2-9b92-11d67b6163b4 /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db ** ** $ ls -alF /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db -rw-rw-r-- 1 sandra sandra 5252320 Jan 16 08:42 /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db ** ** $ ./bin/sstable2json /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db -k $(echo -n 459fb460-5ace-11e2-9b92-11d67b6163b4 | hexdump -e '36/1 %x
Re: LCS not removing rows with all TTL expired columns
. ** ** IMO, before 1.2, LCS was good for CFs without TTL or high delete rate. I have not tested 1.2 LCS behavior, we’re still on 1.0.x ** ** ** ** Best regards / Pagarbiai *Viktor Jevdokimov* Senior Developer Email: viktor.jevdoki...@adform.com Phone: +370 5 212 3063, Fax +370 5 261 0453 J. Jasinskio 16C, LT-01112 Vilnius, Lithuania Follow us on Twitter: @adforminsiderhttp://twitter.com/#!/adforminsider Take a ride with Adform's Rich Media Suitehttp://vimeo.com/adform/richmedia [image: Adform News] http://www.adform.com [image: Adform awarded the Best Employer 2012] http://www.adform.com/site/blog/adform/adform-takes-top-spot-in-best-employer-survey/ Disclaimer: The information contained in this message and attachments is intended solely for the attention and use of the named addressee and may be confidential. If you are not the intended recipient, you are reminded 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. *From:* aaron morton [mailto:aa...@thelastpickle.com] *Sent:* Thursday, January 17, 2013 06:24 *To:* user@cassandra.apache.org *Subject:* Re: LCS not removing rows with all TTL expired columns ** ** Minor compaction (with Size Tiered) will only purge tombstones if all fragments of a row are contained in the SSTables being compacted. So if you have a long lived row, that is present in many size tiers, the columns will not be purged. ** ** (thus compacted compacted) 3 days after all columns for that row had expired Tombstones have to get on disk, even if you set the gc_grace_seconds to 0. If not they do not get a chance to delete previous versions of the column which already exist on disk. So when the compaction ran your ExpiringColumn was turned into a DeletedColumn and placed on disk. ** ** I would expect the next round of compaction to remove these columns. ** ** ** ** There is a new feature in 1.2 that may help you here. It will do a special compaction of individual sstables when they have a certain proportion of dead columns https://issues.apache.org/jira/browse/CASSANDRA-3442 ** ** Also interested to know if LCS helps. ** ** Cheers ** ** - Aaron Morton Freelance Cassandra Developer New Zealand ** ** @aaronmorton http://www.thelastpickle.com ** ** On 17/01/2013, at 2:55 PM, Bryan Talbot btal...@aeriagames.com wrote: According to the timestamps (see original post) the SSTable was written (thus compacted compacted) 3 days after all columns for that row had expired and 6 days after the row was created; yet all columns are still showing up in the SSTable. Note that the column shows now rows when a get for that key is run so that's working correctly, but the data is lugged around far longer than it should be -- maybe forever. ** ** ** ** -Bryan ** ** On Wed, Jan 16, 2013 at 5:44 PM, Andrey Ilinykh ailin...@gmail.com wrote: To get column removed you have to meet two requirements 1. column should be expired 2. after that CF gets compacted ** ** I guess your expired columns are propagated to high tier CF, which gets compacted rarely. So, you have to wait when high tier CF gets compacted. ** ** Andrey ** ** ** ** On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.com wrote: On cassandra 1.1.5 with a write heavy workload, we're having problems getting rows to be compacted away (removed) even though all columns have expired TTL. We've tried size tiered and now leveled and are seeing the same symptom: the data stays around essentially forever. ** ** Currently we write all columns with a TTL of 72 hours (259200 seconds) and expect to add 10 GB of data to this CF per day per node. Each node currently has 73 GB for the affected CF and shows no indications that old rows will be removed on their own. ** ** Why aren't rows being removed? Below is some data from a sample row which should have been removed several days ago but is still around even though it has been involved in numerous compactions since being expired. ** ** $ ./bin/nodetool -h localhost getsstables metrics request_summary 459fb460-5ace-11e2-9b92-11d67b6163b4 /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db ** ** $ ls -alF /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db -rw-rw-r-- 1 sandra sandra 5252320 Jan 16 08:42 /virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db ** ** $ ./bin/sstable2json /virtual/cassandra/data/data
Re: LCS not removing rows with all TTL expired columns
To get column removed you have to meet two requirements
1. column should be expired
2. after that CF gets compacted
I guess your expired columns are propagated to high tier CF, which gets
compacted rarely.
So, you have to wait when high tier CF gets compacted.
Andrey
On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.comwrote:
On cassandra 1.1.5 with a write heavy workload, we're having problems
getting rows to be compacted away (removed) even though all columns have
expired TTL. We've tried size tiered and now leveled and are seeing the
same symptom: the data stays around essentially forever.
Currently we write all columns with a TTL of 72 hours (259200 seconds) and
expect to add 10 GB of data to this CF per day per node. Each node
currently has 73 GB for the affected CF and shows no indications that old
rows will be removed on their own.
Why aren't rows being removed? Below is some data from a sample row which
should have been removed several days ago but is still around even though
it has been involved in numerous compactions since being expired.
$ ./bin/nodetool -h localhost getsstables metrics request_summary
459fb460-5ace-11e2-9b92-11d67b6163b4
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
$ ls -alF
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
-rw-rw-r-- 1 sandra sandra 5252320 Jan 16 08:42
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
$ ./bin/sstable2json
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
-k $(echo -n 459fb460-5ace-11e2-9b92-11d67b6163b4 | hexdump -e '36/1 %x')
{
34353966623436302d356163652d313165322d396239322d313164363762363136336234:
[[app_name,50f21d3d,1357785277207001,d],
[client_ip,50f21d3d,1357785277207001,d],
[client_req_id,50f21d3d,1357785277207001,d],
[mysql_call_cnt,50f21d3d,1357785277207001,d],
[mysql_duration_us,50f21d3d,1357785277207001,d],
[mysql_failure_call_cnt,50f21d3d,1357785277207001,d],
[mysql_success_call_cnt,50f21d3d,1357785277207001,d],
[req_duration_us,50f21d3d,1357785277207001,d],
[req_finish_time_us,50f21d3d,1357785277207001,d],
[req_method,50f21d3d,1357785277207001,d],
[req_service,50f21d3d,1357785277207001,d],
[req_start_time_us,50f21d3d,1357785277207001,d],
[success,50f21d3d,1357785277207001,d]]
}
Decoding the column timestamps to shows that the columns were written at
Thu, 10 Jan 2013 02:34:37 GMT and that their TTL expired at Sun, 13 Jan
2013 02:34:37 GMT. The date of the SSTable shows that it was generated on
Jan 16 which is 3 days after all columns have TTL-ed out.
The schema shows that gc_grace is set to 0 since this data is write-once,
read-seldom and is never updated or deleted.
create column family request_summary
with column_type = 'Standard'
and comparator = 'UTF8Type'
and default_validation_class = 'UTF8Type'
and key_validation_class = 'UTF8Type'
and read_repair_chance = 0.1
and dclocal_read_repair_chance = 0.0
and gc_grace = 0
and min_compaction_threshold = 4
and max_compaction_threshold = 32
and replicate_on_write = true
and compaction_strategy =
'org.apache.cassandra.db.compaction.LeveledCompactionStrategy'
and caching = 'NONE'
and bloom_filter_fp_chance = 1.0
and compression_options = {'chunk_length_kb' : '64',
'sstable_compression' :
'org.apache.cassandra.io.compress.SnappyCompressor'};
Thanks in advance for help in understanding why rows such as this are not
removed!
-Bryan
Re: LCS not removing rows with all TTL expired columns
According to the timestamps (see original post) the SSTable was written
(thus compacted compacted) 3 days after all columns for that row had
expired and 6 days after the row was created; yet all columns are still
showing up in the SSTable. Note that the column shows now rows when a
get for that key is run so that's working correctly, but the data is
lugged around far longer than it should be -- maybe forever.
-Bryan
On Wed, Jan 16, 2013 at 5:44 PM, Andrey Ilinykh ailin...@gmail.com wrote:
To get column removed you have to meet two requirements
1. column should be expired
2. after that CF gets compacted
I guess your expired columns are propagated to high tier CF, which gets
compacted rarely.
So, you have to wait when high tier CF gets compacted.
Andrey
On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.comwrote:
On cassandra 1.1.5 with a write heavy workload, we're having problems
getting rows to be compacted away (removed) even though all columns have
expired TTL. We've tried size tiered and now leveled and are seeing the
same symptom: the data stays around essentially forever.
Currently we write all columns with a TTL of 72 hours (259200 seconds)
and expect to add 10 GB of data to this CF per day per node. Each node
currently has 73 GB for the affected CF and shows no indications that old
rows will be removed on their own.
Why aren't rows being removed? Below is some data from a sample row
which should have been removed several days ago but is still around even
though it has been involved in numerous compactions since being expired.
$ ./bin/nodetool -h localhost getsstables metrics request_summary
459fb460-5ace-11e2-9b92-11d67b6163b4
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
$ ls -alF
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
-rw-rw-r-- 1 sandra sandra 5252320 Jan 16 08:42
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
$ ./bin/sstable2json
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
-k $(echo -n 459fb460-5ace-11e2-9b92-11d67b6163b4 | hexdump -e '36/1 %x')
{
34353966623436302d356163652d313165322d396239322d313164363762363136336234:
[[app_name,50f21d3d,1357785277207001,d],
[client_ip,50f21d3d,1357785277207001,d],
[client_req_id,50f21d3d,1357785277207001,d],
[mysql_call_cnt,50f21d3d,1357785277207001,d],
[mysql_duration_us,50f21d3d,1357785277207001,d],
[mysql_failure_call_cnt,50f21d3d,1357785277207001,d],
[mysql_success_call_cnt,50f21d3d,1357785277207001,d],
[req_duration_us,50f21d3d,1357785277207001,d],
[req_finish_time_us,50f21d3d,1357785277207001,d],
[req_method,50f21d3d,1357785277207001,d],
[req_service,50f21d3d,1357785277207001,d],
[req_start_time_us,50f21d3d,1357785277207001,d],
[success,50f21d3d,1357785277207001,d]]
}
Decoding the column timestamps to shows that the columns were written at
Thu, 10 Jan 2013 02:34:37 GMT and that their TTL expired at Sun, 13 Jan
2013 02:34:37 GMT. The date of the SSTable shows that it was generated on
Jan 16 which is 3 days after all columns have TTL-ed out.
The schema shows that gc_grace is set to 0 since this data is write-once,
read-seldom and is never updated or deleted.
create column family request_summary
with column_type = 'Standard'
and comparator = 'UTF8Type'
and default_validation_class = 'UTF8Type'
and key_validation_class = 'UTF8Type'
and read_repair_chance = 0.1
and dclocal_read_repair_chance = 0.0
and gc_grace = 0
and min_compaction_threshold = 4
and max_compaction_threshold = 32
and replicate_on_write = true
and compaction_strategy =
'org.apache.cassandra.db.compaction.LeveledCompactionStrategy'
and caching = 'NONE'
and bloom_filter_fp_chance = 1.0
and compression_options = {'chunk_length_kb' : '64',
'sstable_compression' :
'org.apache.cassandra.io.compress.SnappyCompressor'};
Thanks in advance for help in understanding why rows such as this are not
removed!
-Bryan
Re: LCS not removing rows with all TTL expired columns
Minor compaction (with Size Tiered) will only purge tombstones if all fragments
of a row are contained in the SSTables being compacted. So if you have a long
lived row, that is present in many size tiers, the columns will not be purged.
(thus compacted compacted) 3 days after all columns for that row had expired
Tombstones have to get on disk, even if you set the gc_grace_seconds to 0. If
not they do not get a chance to delete previous versions of the column which
already exist on disk. So when the compaction ran your ExpiringColumn was
turned into a DeletedColumn and placed on disk.
I would expect the next round of compaction to remove these columns.
There is a new feature in 1.2 that may help you here. It will do a special
compaction of individual sstables when they have a certain proportion of dead
columns https://issues.apache.org/jira/browse/CASSANDRA-3442
Also interested to know if LCS helps.
Cheers
-
Aaron Morton
Freelance Cassandra Developer
New Zealand
@aaronmorton
http://www.thelastpickle.com
On 17/01/2013, at 2:55 PM, Bryan Talbot btal...@aeriagames.com wrote:
According to the timestamps (see original post) the SSTable was written (thus
compacted compacted) 3 days after all columns for that row had expired and 6
days after the row was created; yet all columns are still showing up in the
SSTable. Note that the column shows now rows when a get for that key is
run so that's working correctly, but the data is lugged around far longer
than it should be -- maybe forever.
-Bryan
On Wed, Jan 16, 2013 at 5:44 PM, Andrey Ilinykh ailin...@gmail.com wrote:
To get column removed you have to meet two requirements
1. column should be expired
2. after that CF gets compacted
I guess your expired columns are propagated to high tier CF, which gets
compacted rarely.
So, you have to wait when high tier CF gets compacted.
Andrey
On Wed, Jan 16, 2013 at 11:39 AM, Bryan Talbot btal...@aeriagames.com wrote:
On cassandra 1.1.5 with a write heavy workload, we're having problems getting
rows to be compacted away (removed) even though all columns have expired TTL.
We've tried size tiered and now leveled and are seeing the same symptom: the
data stays around essentially forever.
Currently we write all columns with a TTL of 72 hours (259200 seconds) and
expect to add 10 GB of data to this CF per day per node. Each node currently
has 73 GB for the affected CF and shows no indications that old rows will be
removed on their own.
Why aren't rows being removed? Below is some data from a sample row which
should have been removed several days ago but is still around even though it
has been involved in numerous compactions since being expired.
$ ./bin/nodetool -h localhost getsstables metrics request_summary
459fb460-5ace-11e2-9b92-11d67b6163b4
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
$ ls -alF
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
-rw-rw-r-- 1 sandra sandra 5252320 Jan 16 08:42
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
$ ./bin/sstable2json
/virtual/cassandra/data/data/metrics/request_summary/metrics-request_summary-he-386179-Data.db
-k $(echo -n 459fb460-5ace-11e2-9b92-11d67b6163b4 | hexdump -e '36/1 %x')
{
34353966623436302d356163652d313165322d396239322d313164363762363136336234:
[[app_name,50f21d3d,1357785277207001,d],
[client_ip,50f21d3d,1357785277207001,d],
[client_req_id,50f21d3d,1357785277207001,d],
[mysql_call_cnt,50f21d3d,1357785277207001,d],
[mysql_duration_us,50f21d3d,1357785277207001,d],
[mysql_failure_call_cnt,50f21d3d,1357785277207001,d],
[mysql_success_call_cnt,50f21d3d,1357785277207001,d],
[req_duration_us,50f21d3d,1357785277207001,d],
[req_finish_time_us,50f21d3d,1357785277207001,d],
[req_method,50f21d3d,1357785277207001,d],
[req_service,50f21d3d,1357785277207001,d],
[req_start_time_us,50f21d3d,1357785277207001,d],
[success,50f21d3d,1357785277207001,d]]
}
Decoding the column timestamps to shows that the columns were written at
Thu, 10 Jan 2013 02:34:37 GMT and that their TTL expired at Sun, 13 Jan
2013 02:34:37 GMT. The date of the SSTable shows that it was generated on
Jan 16 which is 3 days after all columns have TTL-ed out.
The schema shows that gc_grace is set to 0 since this data is write-once,
read-seldom and is never updated or deleted.
create column family request_summary
with column_type = 'Standard'
and comparator = 'UTF8Type'
and default_validation_class = 'UTF8Type'
and key_validation_class = 'UTF8Type'
and read_repair_chance = 0.1
and dclocal_read_repair_chance = 0.0
and gc_grace = 0
and min_compaction_threshold = 4
and max_compaction_threshold = 32
and replicate_on_write = true
and compaction_strategy =
