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https://issues.apache.org/jira/browse/HBASE-2600?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13168799#comment-13168799
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[email protected] commented on HBASE-2600:
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I thought the change would be bigger than this. Does it work?
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8723>
Should this be 'starts with'? Are 0x01 and 0x02 good characters to have
here? They are unprintable. Would it be better to have printables? More
friendly to, you know, those humans that have to look at this stuff.
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8724>
Whats this define for?
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8722>
Why this stray ';'?
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8725>
This define name is hard to grok too
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8726>
Whats up w/ your formatting here? Here and a few lines down for the
@return?
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8727>
A bit of a comment here on why this math would help the reader.
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8728>
Can you not just put DELIMITER here? Ditto for the puts above? Do you
have to put it into oneByte first?
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8729>
Would it be error if a null id?
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8730>
method names do not begin with capital letters.
Line is too long
src/main/java/org/apache/hadoop/hbase/HRegionInfo.java
<https://reviews.apache.org/r/3186/#comment8731>
Formatting is off in this method?
src/main/java/org/apache/hadoop/hbase/KeyValue.java
<https://reviews.apache.org/r/3186/#comment8732>
Will this always give same name? Doesn't uuid have time and machine name
inputs?
Does this belong in here anyways?
src/main/java/org/apache/hadoop/hbase/KeyValue.java
<https://reviews.apache.org/r/3186/#comment8734>
line too long
src/main/java/org/apache/hadoop/hbase/KeyValue.java
<https://reviews.apache.org/r/3186/#comment8735>
Would suggest you not change the formatting already in place; blend in
instead (lines too long anyway)
src/main/java/org/apache/hadoop/hbase/client/MetaSearchRow.java
<https://reviews.apache.org/r/3186/#comment8737>
Needs class comment.
What is this class replacing?
src/main/java/org/apache/hadoop/hbase/client/MetaSearchRow.java
<https://reviews.apache.org/r/3186/#comment8738>
public methods need javadoc?
src/main/java/org/apache/hadoop/hbase/client/MetaSearchRow.java
<https://reviews.apache.org/r/3186/#comment8739>
Do we need zeros?
Is this tablename its uuid?
Maybe we can't do uuid if it has host and time factors? Maybe need to
sha1/md5 it? Something that will always give us same answer regardless of when
we hash or where?
- Michael
On 2011-12-13 21:12:33, Alex Newman wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/3186/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2011-12-13 21:12:33)
bq.
bq.
bq. Review request for hbase.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. PART 1 of hbase-4616
bq.
bq. This is an idea that Ryan and I have been kicking around on and off for a
while now.
bq.
bq. 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).
bq.
bq. 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.
bq.
bq. This issue is about changing the way we name regions.
bq.
bq. 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).
bq.
bq. Converting to the new method, we'd have to run a migration on startup
changing the content in meta.
bq.
bq. 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.
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/HConstants.java 1cf58a9
bq. src/main/java/org/apache/hadoop/hbase/HRegionInfo.java 74cb821
bq. src/main/java/org/apache/hadoop/hbase/KeyValue.java be7e2d8
bq. src/main/java/org/apache/hadoop/hbase/catalog/MetaReader.java e5e60a8
bq. src/main/java/org/apache/hadoop/hbase/client/HBaseAdmin.java 6bff130
bq. src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java
6f19d21
bq. src/main/java/org/apache/hadoop/hbase/client/MetaScanner.java 4135e55
bq. src/main/java/org/apache/hadoop/hbase/client/MetaSearchRow.java
PRE-CREATION
bq. src/main/java/org/apache/hadoop/hbase/rest/RegionsResource.java bf85bc1
bq. src/main/java/org/apache/hadoop/hbase/rest/model/TableRegionModel.java
67e7a04
bq. src/test/java/org/apache/hadoop/hbase/HBaseTestingUtility.java 6fca020
bq. src/test/java/org/apache/hadoop/hbase/TestKeyValue.java dc4ee8d
bq. src/test/java/org/apache/hadoop/hbase/client/TestAdmin.java 95712dd
bq.
src/test/java/org/apache/hadoop/hbase/regionserver/TestGetClosestAtOrBefore.java
5f97167
bq. src/test/java/org/apache/hadoop/hbase/regionserver/TestHRegionInfo.java
6e1211b
bq. src/test/java/org/apache/hadoop/hbase/regionserver/TestMemStore.java
a092cf0
bq.
src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java
1997abd
bq.
src/test/java/org/apache/hadoop/hbase/rest/model/TestTableRegionModel.java
b6f0ab5
bq.
bq. Diff: https://reviews.apache.org/r/3186/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
> Attachments:
> 0001-Changed-regioninfo-format-to-use-endKey-instead-of-s.patch
>
>
> 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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