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https://issues.apache.org/jira/browse/HBASE-2600?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13092207#comment-13092207
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Lars Hofhansl commented on HBASE-2600:
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I ran into this partially when I worked on
[HBASE-4071|https://issues.apache.org/jira/browse/HBASE-4071].
One thing I noticed is that getRowOrBefore(...) is actually exposed via
HTableInterface. Do we really want this? If we ever want to get rid of this,
should we at least deprecate this method in HTableInterface now before more -
if any - folks start using it?
Also a question regarding
[HBASE-2531|https://issues.apache.org/jira/browse/HBASE-2531], can we rely on
the fact all table (except - ROOT - and .META.) have the encodedRegionName?
Looking at the patch attached there it seems that regions of old tables (and
ROOT and META - but that's ok) could still have the old names.
> Change how we do meta tables; from tablename+STARTROW+randomid to instead,
> tablename+ENDROW+randomid
> ----------------------------------------------------------------------------------------------------
>
> Key: HBASE-2600
> URL: https://issues.apache.org/jira/browse/HBASE-2600
> Project: HBase
> Issue Type: Improvement
> Reporter: stack
>
> This is an idea that Ryan and I have been kicking around on and off for a
> while now.
> If regionnames were made of tablename+endrow instead of tablename+startrow,
> then in the metatables, doing a search for the region that contains the
> wanted row, we'd just have to open a scanner using passed row and the first
> row found by the scan would be that of the region we need (If offlined
> parent, we'd have to scan to the next row).
> If we redid the meta tables in this format, we'd be using an access that is
> natural to hbase, a scan as opposed to the perverse, expensive
> getClosestRowBefore we currently have that has to walk backward in meta
> finding a containing region.
> This issue is about changing the way we name regions.
> If we were using scans, prewarming client cache would be near costless (as
> opposed to what we'll currently have to do which is first a
> getClosestRowBefore and then a scan from the closestrowbefore forward).
> Converting to the new method, we'd have to run a migration on startup
> changing the content in meta.
> Up to this, the randomid component of a region name has been the timestamp of
> region creation. HBASE-2531 "32-bit encoding of regionnames waaaaaaayyyyy
> too susceptible to hash clashes" proposes changing the randomid so that it
> contains actual name of the directory in the filesystem that hosts the
> region. If we had this in place, I think it would help with the migration to
> this new way of doing the meta because as is, the region name in fs is a hash
> of regionname... changing the format of the regionname would mean we generate
> a different hash... so we'd need hbase-2531 to be in place before we could do
> this change.
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