Re: pgsql: Adjust string comparison in jsonpath

From: Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com>
To: Alexander Korotkov <akorotkov(at)postgresql(dot)org>, pgsql-committers(at)lists(dot)postgresql(dot)org
Subject: Re: pgsql: Adjust string comparison in jsonpath
Date: 2019-08-11 21:03:50
Message-ID: 0ed83a33-d900-466a-880a-70ef456c721f@2ndQuadrant.com
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On 8/11/19 4:10 PM, Alexander Korotkov wrote:
> Adjust string comparison in jsonpath
>
> We have implemented jsonpath string comparison using default database locale.
> However, standard requires us to compare Unicode codepoints. This commit
> implements that, but for performance reasons we still use per-byte comparison
> for "==" operator. Thus, for consistency other comparison operators do per-byte
> comparison if Unicode codepoints appear to be equal.
>
> In some edge cases, when same Unicode codepoints have different binary
> representations in database encoding, we diverge standard to achieve better
> performance of "==" operator. In future to implement strict standard
> conformance, we can do normalization of input JSON strings.
>

This appears to have upset prion when testing on en_US.iso885915.

cheers

andrew

--
Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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