[
https://issues.apache.org/jira/browse/PARQUET-2237?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17697256#comment-17697256
]
ASF GitHub Bot commented on PARQUET-2237:
-----------------------------------------
yabola commented on PR #1023:
URL: https://github.com/apache/parquet-mr/pull/1023#issuecomment-1457669848
@wgtmac @gszadovszky
I have a proposal to automatically build BloomFilter with a more precise
size. I create a jira https://issues.apache.org/jira/browse/PARQUET-2254 and I
hope to get your opinions, thank you.
> Now the usage is to specify the size, and then build BloomFilter. In
general scenarios, it is actually not sure how much the distinct value is.
If BloomFilter can be automatically generated according to the data, the
file size can be reduced and the reading efficiency can also be improved.
I have an idea that the user can specify a maximum BloomFilter filter size,
then we build several BloomFilter at the same time, we can use the largest
BloomFilter as a counting tool( If there is no hit when inserting a value, the
counter will be +1, of course this may be imprecise but enough)
Then at the end of the write, choose a BloomFilter of a more appropriate
size when the file is finally written.
I want to implement this feature and
> Improve performance when filters in RowGroupFilter can match exactly
> --------------------------------------------------------------------
>
> Key: PARQUET-2237
> URL: https://issues.apache.org/jira/browse/PARQUET-2237
> Project: Parquet
> Issue Type: Improvement
> Reporter: Mars
> Priority: Major
>
> If we can accurately judge by the minMax status, we don’t need to load the
> dictionary from filesystem and compare one by one anymore.
> Similarly , Bloomfilter needs to load from filesystem, it may costs time and
> memory. If we can exactly determine the existence/nonexistence of the value
> from minMax or dictionary filters , then we can avoid using Bloomfilter to
> Improve performance.
> For example,
> # read data greater than {{x1}} in the block, if minMax in status is all
> greater than {{{}x1{}}}, then we don't need to read dictionary and compare
> one by one.
> # If we already have page dictionaries and have compared one by one, we
> don't need to read BloomFilter and compare.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
