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https://issues.apache.org/jira/browse/CASSANDRA-12937?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17713549#comment-17713549
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Claude Warren commented on CASSANDRA-12937:
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I am trying to follow the guidance I was given. At this point I think we need
to have a discussion on the dev mailing list to arrive at a consensus of how
this should be done.
Currently CompressionParams takes the class name and the parameters. It
extracts chunk_length_kb (or chunk_length_in_kb) and min_compress_ratio from
the parameters and uses them to build the CompressionParams instance.
The table below outlines the parameters and where they are used. Blue cells
indicate proposed changes.
||Parameter||CompressionParam as map||CompressionParam as
Serializer||CQL||Notes||
|chunk_length_in_kb |X|X|X| |
|chunk_length_kb|(deprecated - read not written)| | | |
|chunk_length|X( proposed)| | |chunk length with DataStorageSpec suffix|
|crc_check_chance|(deprecated - read not written )| |X|crc_check_chance is not
used in CompressionParam|
|min_compress_ratio|X| | | |
|max_compressed_length| |X| |Proposed to add to map input as a string with
DataStorageSpec suffix|
|lz4_compressor_type|X|X|X| |
|{{lz4_high_compressor_level}}|X|X|X| |
|{{compression_level}}|X|X|X|Zstd compressor param|
> Default setting (yaml) for SSTable compression
> ----------------------------------------------
>
> Key: CASSANDRA-12937
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12937
> Project: Cassandra
> Issue Type: Improvement
> Components: Local/Config
> Reporter: Michael Semb Wever
> Assignee: Claude Warren
> Priority: Low
> Labels: AdventCalendar2021, lhf
> Fix For: 5.x
>
> Time Spent: 3h
> Remaining Estimate: 0h
>
> In many situations the choice of compression for sstables is more relevant to
> the disks attached than to the schema and data.
> This issue is to add to cassandra.yaml a default value for sstable
> compression that new tables will inherit (instead of the defaults found in
> {{CompressionParams.DEFAULT}}.
> Examples where this can be relevant are filesystems that do on-the-fly
> compression (btrfs, zfs) or specific disk configurations or even specific C*
> versions (see CASSANDRA-10995 ).
> +Additional information for newcomers+
> Some new fields need to be added to {{cassandra.yaml}} to allow specifying
> the field required for defining the default compression parameters. In
> {{DatabaseDescriptor}} a new {{CompressionParams}} field should be added for
> the default compression. This field should be initialized in
> {{DatabaseDescriptor.applySimpleConfig()}}. At the different places where
> {{CompressionParams.DEFAULT}} was used the code should call
> {{DatabaseDescriptor#getDefaultCompressionParams}} that should return some
> copy of configured {{CompressionParams}}.
> Some unit test using {{OverrideConfigurationLoader}} should be used to test
> that the table schema use the new default when a new table is created (see
> CreateTest for some example).
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