[jira] [Commented] (HAWQ-944) Numutils.c: pg_ltoa and pg_itoa functions allocate unnecessary amount of bytes

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HAWQ-944?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15387996#comment-15387996 ] 

ASF GitHub Bot commented on HAWQ-944:
-------------------------------------

GitHub user kavinderd opened a pull request:

    https://github.com/apache/incubator-hawq/pull/808

    HAWQ-944. Implement new pg_ltoa function as per postgres

    

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/kavinderd/incubator-hawq HAWQ-944

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/incubator-hawq/pull/808.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #808
    
----
commit fb32032529eeec680d921383c056168910d99da9
Author: Kavinder Dhaliwal <ka...@gmail.com>
Date:   2016-07-20T23:14:10Z

    HAWQ-944. Implement new pg_ltoa function as per postgres

----


> Numutils.c: pg_ltoa and pg_itoa functions allocate unnecessary amount of bytes
> ------------------------------------------------------------------------------
>
>                 Key: HAWQ-944
>                 URL: https://issues.apache.org/jira/browse/HAWQ-944
>             Project: Apache HAWQ
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Kavinder Dhaliwal
>            Assignee: Kavinder Dhaliwal
>            Priority: Minor
>
> The current implementations of {{pg_ltoa}} and {{pg_itoa}} allocate a 33 byte char array and set the input pointer to that array. This is far too many bytes than needed to translate an int16 or int32 to a string
> int32 -> 10 bytes maximum + 1 sign bit + '\0' = 12 bytes
> int16 ->  5 bytes maximum  + 1 sign bit + '\0' = 7 bytes
> When HAWQ/Greenplum forked from Postgres the two functions simply delegated to {{sprintf}} so an optimization was introduced that involved the 33 byte solution. Postgres itself implemented these functions in commit https://github.com/postgres/postgres/commit/4fc115b2e981f8c63165ca86a23215380a3fda66 that require a 12 byte maximum char pointer.
> This is a minor improvement that can be made to the HAWQ codebase and it's relatively little effort to do so.



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