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https://issues.apache.org/jira/browse/HBASE-2600?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13166465#comment-13166465
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[email protected] commented on HBASE-2600:
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This patch doesn't seem to be coherent. It seems to be a mix of things Alex.
Good on you.
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/2965/#comment8601>
This is odd.
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/2965/#comment8600>
This should do Bytes.toBytes() and pass the String version (else you are
susceptible to the machines' locale -- toBytes does UTF-8 all the time).
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/2965/#comment8602>
Not sure I grok this change.
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/2965/#comment8603>
Is this change related to this patch?
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/2965/#comment8604>
Should change the javadoc? Can we not get the table name any more once
this change goes in? Get the table name from HRI I mean? We'd have to do look
up into a Map of UUID to tablename?
Yeah, what is a tableNameUUID? Its just a UUID?
- Michael
On 2011-11-29 22:58:47, Alex Newman wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/2965/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2011-11-29 22:58:47)
bq.
bq.
bq. Review request for hbase.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. The issue is we have to have a custom compareter for metakey/rootkey
scanning to work. One of the reasons why this is required is that the
tablenames are currently lexically sorted.
bq.
bq.
bq. This addresses bug HBASE-2600.
bq. https://issues.apache.org/jira/browse/HBASE-2600
bq.
bq.
bq. Diffs
bq. -----
bq.
bq. src/main/java/org/apache/hadoop/hbase/HRegionInfo.java 0c1fa3f
bq.
bq. Diff: https://reviews.apache.org/r/2965/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq.
bq. Thanks,
bq.
bq. Alex
bq.
bq.
> 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: Sub-task
> Reporter: stack
> Assignee: Alex Newman
>
> 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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