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https://issues.apache.org/jira/browse/CASSANDRA-47?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13067781#comment-13067781
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Pavel Yaskevich commented on CASSANDRA-47:
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bq. A small detail though is that I would store the chunk offsets instead of
the chunk sizes, the reason being that it's more resilient to corruption
(typically, with chunk sizes, if the first entry is corrupted you're screwed,
with offsets, you only have one or two chunks that are unreadable).
+1 if we will go with a separate file. I'm thinking if we will go with a
separate file I will use the same strategy as I did in v1 - store chunk size at
the beginning of the chunk and re-read it instead of keeping it in memory
(lowers memory usage for larger files).
bq. After all, CompressedDataFile is just a BRAF with a fixed buffer size, and
a mechanism to translate pre-compaction file position to compressed file
position (roughly). So I'm pretty sure it should be possible to have
CompressedDataFile extend BRAF with minimum refactoring (of BRAF that is). It
would also lift for free the limitation of not have read-write compressed file
(not that we use them but ...).
To extend BRAF will will need to split it into Input/Output classes which will
imply refactoring of skip cache functionality and other parts of that class.
I'd rather create a separate issue to do that after compression is committed
instead of putting all eggs in one basket.
+1 on everything else.
> 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.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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