[jira] [Comment Edited] (IGNITE-3959) SQL Dates performance issues

["Andrew Mashenkov (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-3959?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15516127#comment-15516127 ] 

Andrew Mashenkov edited comment on IGNITE-3959 at 9/23/16 11:04 AM:
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See IgniteH2Indexing.wrap() method. We use ValueDate\ValueTime classes provided by H2 for building H2 objects.
These classes uses java.util.Calendar which causes well known issues. [Details can be found in this and related articles| http://java-performance.info/jsr-310-java-8-datetime-library-performance-well-joda-time-2-3-j-u-calendar/].

We can replace ValueDate\ValueTime classes with own implementation depending on H2 internals (see H2 class method DateTimeUtils.dateValueFromCalendar). Then we'll must bother about compatibility with other H2 versions.

In H2 version we use, holds cache java.util.Calendar instance in static field and synchronize every operation on it. 

We can make a pool of Calendar instances to improve performance in multi-thread environments or replace java.util.Calendar.
JodaTime library seems to be a good alternative to java.util.Calendar, but it is an external dependency and  futhermore it must be updated along with JDK TZ Info updates. 









was (Author: amashenkov):
See IgniteH2Indexing.wrap() method. We use ValueDate\ValueTime classes provided by H2 for building H2 objects.
These classes uses java.util.Calendar which causes well known issues. [Details can be found in this and related articles| http://java-performance.info/jsr-310-java-8-datetime-library-performance-well-joda-time-2-3-j-u-calendar/].

We can replace ValueDate\ValueTime classes with our classes with own implementation depending on H2 internals (see H2 class method DateTimeUtils.dateValueFromCalendar). Then we'll must bother about compatibility with other H2 versions.

In H2 version we use, holds cache java.util.Calendar instance in static field and synchronize every operation on it. 

We can make a pool of Calendar instances to improve performance in multi-thread environments or replace java.util.Calendar.
JodaTime library seems to be a good alternative to java.util.Calendar, but it is an external dependency and  futhermore it must be updated along with JDK TZ Info updates. 








> SQL Dates performance issues
> ----------------------------
>
>                 Key: IGNITE-3959
>                 URL: https://issues.apache.org/jira/browse/IGNITE-3959
>             Project: Ignite
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 1.6, 1.7
>            Reporter: Andrew Mashenkov
>              Labels: performance
>
> SqlFieldsQueries slowdown on date\time fields processing due to ineffective java.util.Calendar usage for date manipulation by H2 database.



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