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https://issues.apache.org/jira/browse/CASSANDRA-47?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13071172#comment-13071172
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Pavel Yaskevich edited comment on CASSANDRA-47 at 7/26/11 4:04 PM:
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We need to decide do we need to do this per CF or at the global level.
I don't think that mmap of the compressed file is a good idea because we anyway
won't be able to avoid a buffer copies as we do with uncompressed data (see
MappedFileDataInput). Agree with other arguments not related to mmap mode.
bq. Let's add the 'compression algorithm' in the compressionInfo component.
It's fine to hard set it to "Snappy" for writes and ignore the value on read
for now.
We will need that field to be fixed size or size + value because just writing a
string at the header could potentially be dangerous.
bq. In SSTR and SSTW, we can use the isCompressed SSTable flag instead of 'if
(components.contains(Component.COMPRESSION_INFO))'.
I will remove one use of it in the SSTW but in the SSTR it is used in the
static method where we don't have isCompressed flag.
was (Author: xedin):
We need to decide do we need to do this per CF or at the global level.
I don't think that mmap of the compressed file is a good idea because we anyway
won't be able to avoid a buffer copies as we do with uncompressed data (see
MappedFileDataInput). Agree with other arguments not related to mmap mode.
bq. In SSTR and SSTW, we can use the isCompressed SSTable flag instead of 'if
(components.contains(Component.COMPRESSION_INFO))'.
I will remove one use of it in the SSTW but in the SSTR it is used in the
static method where we don't have isCompressed flag.
> SSTable compression
> -------------------
>
> Key: CASSANDRA-47
> URL: https://issues.apache.org/jira/browse/CASSANDRA-47
> Project: Cassandra
> Issue Type: New Feature
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Pavel Yaskevich
> Labels: compression
> Fix For: 1.0
>
> Attachments: CASSANDRA-47-v2.patch, CASSANDRA-47-v3-rebased.patch,
> CASSANDRA-47-v3.patch, CASSANDRA-47.patch, snappy-java-1.0.3-rc4.jar
>
>
> We should be able to do SSTable compression which would trade CPU for I/O
> (almost always a good trade).
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