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https://issues.apache.org/jira/browse/HIVE-4642?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Teddy Choi updated HIVE-4642:
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Attachment: Hive-Vectorized-Query-Execution-Design-rev10.docx
I wrote "LIKE and REGEXP expressions:" section in "Filter operator". Following
is the added text.
{quote}
Filter condition expressions
LIKE and REGEXP expressions:
LIKE and REGEXP expressions find any strings fitting a pattern. They compile a
pattern on creation, and find strings on evaluation.
Both kinds of expression use the Java regular expression package. REGEXP
expressions use the package as it is. But LIKE expressions have different
grammar, so they need conversion. “%” is converted to “.*” and “_” is converted
to “.”. AbstractFilterStringColLikeStringScalar class defines common behaviors.
FilterStringColLikeStringScalar class and FilterStringColRegExpStringScalar
class implement differences.
There are simple and frequently used patterns; such as prefix match, suffix
match, middle match, exact match, and phone numbers. There are optimized
implementations for them. They evaluate using byte arrays directly to avoid
UTF-8 decoding load.
{quote}
This file is edited on Word for Mac 2011, so it may have incompatibilities.
> Implement vectorized RLIKE and REGEXP filter expressions
> --------------------------------------------------------
>
> Key: HIVE-4642
> URL: https://issues.apache.org/jira/browse/HIVE-4642
> Project: Hive
> Issue Type: Sub-task
> Reporter: Eric Hanson
> Assignee: Teddy Choi
> Attachments: HIVE-4642-1.patch, HIVE-4642.2.patch,
> HIVE-4642.3.patch.txt, Hive-Vectorized-Query-Execution-Design-rev10.docx
>
>
> See title. I will add more details next week. The goal is (a) make this work
> correctly and (b) optimize it as well as possible, at least for the common
> cases.
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