Re: proposal: searching in array function - array_position - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: proposal: searching in array function - array_position
Date
Msg-id CAFj8pRAyDyPQSb5ZdH0KzLB_e1xV6aQw3xXN1NCAdhN=J9gxxA@mail.gmail.com
Whole thread Raw
In response to Re: proposal: searching in array function - array_position  (Jim Nasby <Jim.Nasby@BlueTreble.com>)
Responses Re: proposal: searching in array function - array_position  (Jim Nasby <Jim.Nasby@BlueTreble.com>)
List pgsql-hackers


2015-03-11 22:14 GMT+01:00 Jim Nasby <Jim.Nasby@bluetreble.com>:
On 3/11/15 1:29 AM, Pavel Stehule wrote:

    What is this comment supposed to mean? There is no 'width_array'...


It is typo (I am sorry) - should be width_bucket(, array)

http://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=e80252d424278abf65b624669c8e6b3fe8587cac

The code is similar, but it expect large **sorted** input. array_offset
works on unsorted (alphabetical unsorted) data sets - like days of week ..

The functions are serving rather different purposes, so I'm not sure it's worth mentioning. If we do want to mention it, then something like the following should be added to *both* functions:

ok, I removed this note.

I added  comment about wrapping and I simplified a code there - this method is used more time in pg for same purposes.

Merged Jim's changes in doc

Pavel

 
 

 * This code is similar to width_bucket()

and

 * This code is similar to array_offset()

Incidentally, isn't it bad that we're doing all these static assignments inside the loop in width_bucket? Or can we count on the compiler to recognize this?

http://lnk.nu/github.com/1dvrr.c

--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com

Attachment

pgsql-hackers by date:

Previous
From: Jim Nasby
Date:
Subject: Re: Proposal : REINDEX xxx VERBOSE
Next
From: Jim Nasby
Date:
Subject: Re: proposal: searching in array function - array_position