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https://issues.apache.org/jira/browse/HBASE-661?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12629639#action_12629639
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Clint Morgan commented on HBASE-661:
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This seems easy enough at first glance. Just associate an (optional)
WritableCompartor<byte[]> with each table. If a table has this comparator then
use it (this logic seems to belong in the new HStoreKey.compareTwoRowKeys).
Things get more tricky I think when taking the META table into account. I
suppose I need to rework the way META rows are being compared to use the tables
comparator for the row's bits in each meta key.
So If I have two tables A, and B with 2 regions each, and B has a custom,
reverse, comparator, then I want a META laid out like:
A,1,5
A,5,
B,9,5
B,5,
So basically the META table uses a custom comparator that is composed of the
comparators for each Table.
Any advice before I start digging deeper? Are there many places where we assume
that row keys are lexocographiclly sorted?
> Allow to specify a user supplied row key comparator for a table
> ----------------------------------------------------------------
>
> Key: HBASE-661
> URL: https://issues.apache.org/jira/browse/HBASE-661
> Project: Hadoop HBase
> Issue Type: New Feature
> Components: client, master, regionserver
> Affects Versions: 0.2.0
> Reporter: Clint Morgan
> Assignee: Clint Morgan
>
> Now that row keys are byte arrays, users should be able to specify a
> comparator at table creation time.
> My use case for this is to implement secondary indexes. In this case, row
> keys for the index tables will be constructed from an optional prefix of the
> original row key as well as the content of column that is being indexed. Then
> the comparator will first compare based on the key prefix, and break ties by
> deserializing the column values and using the deserialized type's compareTo
> method.
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