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https://issues.apache.org/jira/browse/CASSANDRA-4917?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Christian Spriegel updated CASSANDRA-4917:
------------------------------------------
Description:
The goal of this ticket is to reduce the amount of tombstones created from
ExpiringColumns.
Currently tombstones will always stay a full gc_grace time, which is not
neccessary for ExpiringColumns. We only need to ensure that ExpiringColumn and
tombstone together live as long as gc_grace. If the ExpiringColumn's
TTL>=gc_grace then we can create an already gcable tombstone and drop that
instantly.
My initial proposal was to use the ExpiringColumns creation-timestamp as
deletiontime for the tombstone, but Sylvain pointed out that we should not mix
local and client timestamps. So I changed it to this:
{code}
public static Column create(ByteBuffer name, ByteBuffer value, long timestamp,
int timeToLive, int localExpirationTime, int expireBefore,
IColumnSerializer.Flag flag)
{
if (localExpirationTime >= expireBefore || flag ==
IColumnSerializer.Flag.PRESERVE_SIZE)
return new ExpiringColumn(name, value, timestamp, timeToLive,
localExpirationTime);
// the column is now expired, we can safely return a simple tombstone
return new DeletedColumn(name, localExpirationTime-timeToLive, timestamp);
// return new DeletedColumn(name, localExpirationTime, timestamp); // old
code
}
{code}
This was discussed on the mailinglist:
http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/repair-compaction-and-tombstone-rows-td7583481.html
was:
The goal of this ticket is to reduce the amount of tombstones created from
ExpiringColumns.
Currently tombstones will always stay a full gc_grace time, which is not
neccessary for ExpiringColumns. We only need to ensure that ExpiringColumn and
tombstone together live as long as gc_grace. If the ExpiringColumn's
TTL>=gc_grace then we can create an already gcable tombstone and drop that
instantly.
My initial proposal was to use the ExpiringColumns creation-timestamp as
deletiontime for the tombstone, but Sylvain pointed out that we should not mix
local and client timestamps. So I changed it to this:
{code}
public static Column create(ByteBuffer name, ByteBuffer value, long timestamp,
int timeToLive, int localExpirationTime, int expireBefore,
IColumnSerializer.Flag flag)
{
if (localExpirationTime >= expireBefore || flag ==
IColumnSerializer.Flag.PRESERVE_SIZE)
return new ExpiringColumn(name, value, timestamp, timeToLive,
localExpirationTime);
// the column is now expired, we can safely return a simple tombstone
return new DeletedColumn(name, *localExpirationTime-timeToLive*, timestamp);
// return new DeletedColumn(name, localExpirationTime, timestamp); // old
code
}
{code}
This was discussed on the mailinglist:
http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/repair-compaction-and-tombstone-rows-td7583481.html
> Optimize tombstone creation for ExpiringColumns
> -----------------------------------------------
>
> Key: CASSANDRA-4917
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4917
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Christian Spriegel
>
> The goal of this ticket is to reduce the amount of tombstones created from
> ExpiringColumns.
> Currently tombstones will always stay a full gc_grace time, which is not
> neccessary for ExpiringColumns. We only need to ensure that ExpiringColumn
> and tombstone together live as long as gc_grace. If the ExpiringColumn's
> TTL>=gc_grace then we can create an already gcable tombstone and drop that
> instantly.
> My initial proposal was to use the ExpiringColumns creation-timestamp as
> deletiontime for the tombstone, but Sylvain pointed out that we should not
> mix local and client timestamps. So I changed it to this:
> {code}
> public static Column create(ByteBuffer name, ByteBuffer value, long
> timestamp, int timeToLive, int localExpirationTime, int expireBefore,
> IColumnSerializer.Flag flag)
> {
> if (localExpirationTime >= expireBefore || flag ==
> IColumnSerializer.Flag.PRESERVE_SIZE)
> return new ExpiringColumn(name, value, timestamp, timeToLive,
> localExpirationTime);
> // the column is now expired, we can safely return a simple tombstone
> return new DeletedColumn(name, localExpirationTime-timeToLive, timestamp);
> // return new DeletedColumn(name, localExpirationTime, timestamp); // old
> code
> }
> {code}
> This was discussed on the mailinglist:
> http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/repair-compaction-and-tombstone-rows-td7583481.html
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