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Posted to dev@asterixdb.apache.org by as...@googlecode.com on 2015/08/10 10:00:09 UTC
Issue 924 in asterixdb: Secondary btree index should not have a
bloomfilter on it since the filter is not used for range search which is
always the case for secondary index search
Status: Accepted
Owner: kiss...@gmail.com
Labels: Type-Enhancement Priority-Medium
New issue 924 by kiss...@gmail.com: Secondary btree index should not have a
bloomfilter on it since the filter is not used for range search which is
always the case for secondary index search
https://code.google.com/p/asterixdb/issues/detail?id=924
Currently, all secondary index searches are considered as range search due
to the fact that secondary index keys are not unique. Since bloomfilter is
only used for point lookup, secondary btree index should not have a
bloomfilter on it.
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Re: Issue 924 in asterixdb: Secondary btree index should not have a
bloomfilter on it since the filter is not used for range search which is
always the case for secondary index search
Posted by as...@googlecode.com.
Comment #4 on issue 924 by kiss...@gmail.com: Secondary btree index should
not have a bloomfilter on it since the filter is not used for range search
which is always the case for secondary index search
https://code.google.com/p/asterixdb/issues/detail?id=924
Discussion conclusion: secondary btree index will not have a bloomfilter on
it.
The reasons are as follows:
1. Secondary btree index search can't use Bloomfilter for range searches
since , in general, Bloomfilter can only be used for point lookup, i.e.,
single value equality predicate on the indexed key such as user_id (primary
key field) = 10.
2. Secondary btree index search can't use Bloomfilter for point lookup
either such as price = 20 since Bloomfilter in secondary btree index
captures not only secondary key but also primary key, but search predicate
only includes secondary key.
3. Delete operation in secondary index may use the Bloomfilter to check the
existence of the entry to be deleted, but the entry to be deleted will
exist always when the delete operation is executed since the delete
operation always preceded by the search operation. So, checking Bloomfilter
in the situation is useless overhead.
Based on 1,2, and 3, Bloomfilter on secondary btree index is useless.
Therefore, this will be removed.
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Re: Issue 924 in asterixdb: Secondary btree index should not have a
bloomfilter on it since the filter is not used for range search which is
always the case for secondary index search
Posted by as...@googlecode.com.
Comment #3 on issue 924 by che...@gmail.com: Secondary btree index should
not have a bloomfilter on it since the filter is not used for range search
which is always the case for secondary index search
https://code.google.com/p/asterixdb/issues/detail?id=924
@Young-Seok: do you want to summarize our discussion today to close this
discussion?
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Re: Issue 924 in asterixdb: Secondary btree index should not have a
bloomfilter on it since the filter is not used for range search which is
always the case for secondary index search
Posted by as...@googlecode.com.
Comment #2 on issue 924 by kiss...@gmail.com: Secondary btree index should
not have a bloomfilter on it since the filter is not used for range search
which is always the case for secondary index search
https://code.google.com/p/asterixdb/issues/detail?id=924
Yes. We haven't been exploiting that opportunity.
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Re: Issue 924 in asterixdb: Secondary btree index should not have a
bloomfilter on it since the filter is not used for range search which is
always the case for secondary index search
Posted by as...@googlecode.com.
Comment #1 on issue 924 by che...@gmail.com: Secondary btree index should
not have a bloomfilter on it since the filter is not used for range search
which is always the case for secondary index search
https://code.google.com/p/asterixdb/issues/detail?id=924
Then I would challenge the approach of "always doing a range search on a
secondary index." What if we have a condition "price = 20" where there is
a secondary B-tree on "price"? Clearly a bloom filter can help this
predicate. Do we miss an opportunity of optimization here?
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