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https://issues.apache.org/jira/browse/CASSANDRA-1041?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12863611#action_12863611
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Schubert Zhang commented on CASSANDRA-1041:
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@Jonathan,
Yes, we understand that major compactions will clean the tombstones. We add
this configuration based on following reasons:
(1) In same application, there is no delete operation or very seldom delete
operation.
(2) We still want to manually major compact old data to reduce the number of
SSTables (but need not a single big one).
(3) In some filesystem, too big file gains inefficacy.
For minor compactions, "minimumCompactionThreshold" and
"maximumCompactionThreshold" are just the number of SSTables, but not size. We
want use size threshold to avoid too many minor compactions in background,
which cost too many disk IO and CPU and memory.
The tow configurable options are optional for users.
@Stu,
Yes, I also prefer to create multiple SSTables (rather than 1) according to
size threshold (in our another project, it works well). But I think the
"disjoint key ranges" is not so necessary in cassandra.
> Skip large size (Configurable) SSTable in minor or/and major compaction
> -----------------------------------------------------------------------
>
> Key: CASSANDRA-1041
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1041
> Project: Cassandra
> Issue Type: New Feature
> Components: Core
> Reporter: Schubert Zhang
> Priority: Minor
> Attachments: CASSANDRA-1041-0.6.1.patch, CASSANDRA-1041-0.6.patch
>
>
> When the SSTable files are large enough, such as 100GB, the compaction
> (include minor and major) cost is big (disk IO, CPU, memory), etc.
> In some applications, we accept not compcating all SSTables to the final very
> large ones.
> This feature provide two optional configurable attributes
> MinorCompactSkipInGB and MajorCompactSkipInGB for each ColumnFamily.
> The optional MinorCompactSkipInGB attribute specifies the maximum size of
> SSTables which will be compcated in minor-compaction. The SSTables larger
> than MinorCompactSkipInGB will be skipped. The optional MajorCompactSkipInGB
> attribute is same for major-compaction.
> The default of these attributes are 0, means do not skip, just as current
> 0.6.1.
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