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https://issues.apache.org/jira/browse/HBASE-12853?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14280461#comment-14280461
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Michael Segel commented on HBASE-12853:
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"An implemented one is OneBytePrefixKeySalter, where the prefix is
hash(RowKey)%buckets"
That's fine. But now if I have another client, I have to know that the table is
bucketed. (Yes, I am refusing to use the term salt when talking about this...
:-)
And not only do you need to know that the table is bucketed, you need to know
the number of buckets. You are also assuming that the individual is using a
java application to query the data. What happens if they are not?
And that they've got the Intel library.
If its done server side all of that goes away.
> distributed write pattern to replace ad hoc 'salting'
> -----------------------------------------------------
>
> Key: HBASE-12853
> URL: https://issues.apache.org/jira/browse/HBASE-12853
> Project: HBase
> Issue Type: New Feature
> Reporter: Michael Segel
> Priority: Minor
>
> In reviewing HBASE-11682 (Description of Hot Spotting), one of the issues is
> that while 'salting' alleviated regional hot spotting, it increased the
> complexity required to utilize the data.
> Through the use of coprocessors, it should be possible to offer a method
> which distributes the data on write across the cluster and then manages
> reading the data returning a sort ordered result set, abstracting the
> underlying process.
> On table creation, a flag is set to indicate that this is a parallel table.
> On insert in to the table, if the flag is set to true then a prefix is added
> to the key. e.g. <region server#>- or <region server #|| where the region
> server # is an integer between 1 and the number of region servers defined.
> On read (scan) for each region server defined, a separate scan is created
> adding the prefix. Since each scan will be in sort order, its possible to
> strip the prefix and return the lowest value key from each of the subsets.
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