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https://issues.apache.org/jira/browse/HBASE-9203?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13744906#comment-13744906
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rajeshbabu commented on HBASE-9203:
-----------------------------------
bq. What if user specifies two indices on the same set of columns but in
different order ?
The two indices will be considered as independent.
Lets suppose c1,c2 are the columns and indices are [idx1,c1,c2],[idx2,c2,c1]
For some queries where c1 has equal condition and c2 has range condition then
idx1 will considered optimal index.
Similarly if c2 has equal condition then idx2 will be considered as optimal
index.
bq. Was there a typo above (w.r.t. the parameter name) ?
Presently not given any configuration for max index name length. I will add a
configuration for this.
This is different from maxValueLength.
bq. If the max length is changed after index table is created and written to,
would index row key parsing be affected ?
I assume you mean max value length? Yes index rowkey parsing will have effect,
We need to validate this properly and should not allow to modify
maxValueLength.
bq. What if the maxValueLength cannot cover the actual value for indexed column
from the user query ?
That record wont come in result.
bq. Since the midpoint for index table region may not be chosen for the split,
it is possible that the daughter regions of index region may have (quite)
different amount of data. How can we mitigate this effect ?
Index region should split along with user region split only, we are avoiding
splitting index region from external split requests. There should not be a
problem.
> Secondary index support through coprocessors
> --------------------------------------------
>
> Key: HBASE-9203
> URL: https://issues.apache.org/jira/browse/HBASE-9203
> Project: HBase
> Issue Type: New Feature
> Affects Versions: 0.98.0
> Reporter: rajeshbabu
> Assignee: rajeshbabu
> Attachments: SecondaryIndex Design.pdf
>
>
> We have been working on implementing secondary index in HBase and open
> sourced on hbase 0.94.8 version.
> The project is available on github.
> https://github.com/Huawei-Hadoop/hindex
> This Jira is to support secondary index on trunk(0.98).
> Following features will be supported.
> - multiple indexes on table,
> - multi column index,
> - index based on part of a column value,
> - equals and range condition scans using index, and
> - bulk loading data to indexed table (Indexing done with bulk load)
> Most of the kernel changes needed for secondary index is available in trunk.
> Very minimal changes needed for it.
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