Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:98409
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.214.43 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <CADyq6sJYvrQt9fYz-LZfPYZ68ibjUP4pkCCaRTYX+0uLyTVuLw@mail.gmail.com>
References: <CADxrgCP4Mt=Jh_zi2qOXEyt2DTbnDFUb2gkxHg8NgeECL5j8_A@mail.gmail.com>
 <CADxrgCNXyWQ+3Uhiq7NECtVMi4EP29Kq_Qryr5rLDgfwGw93xQ@mail.gmail.com> <CADyq6sJYvrQt9fYz-LZfPYZ68ibjUP4pkCCaRTYX+0uLyTVuLw@mail.gmail.com>
Date: Mon, 6 Mar 2017 10:29:54 -0500
Message-ID: <CADxrgCN5Cpxr5137e6tONSxAiNqWMZUbB7ii77SKogu_=6Escw@mail.gmail.com>
To: Marco Pivetta <ocramius@gmail.com>
Cc: PHP Internals List <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a114051263c8cb9054a119154
Subject: Re: [PHP-DEV] Re: [RFC] Extended String Types For PDO
From: adam.baratz@gmail.com (Adam Baratz)

--001a114051263c8cb9054a119154
Content-Type: text/plain; charset=UTF-8

>
> Reading some random documents online (bear with me, doing it from the
> phone), this seems to be irrelevant for MySQL, and an edge case dealing
> with MSSQL. Is there a runnable functional test case demonstrating the
> practical issue behind this addition?
>

I wouldn't characterize this as edge case for MSSQL. Implicit casts have
very real costs:
https://www.sqlskills.com/blogs/jonathan/implicit-conversions-that-cause-index-scans/

Part of my day job is supporting hundreds of engineers who use PHP to query
MSSQL. Our DBAs are very adamant about making sure we quote strings
correctly. We have a hackish solution for this. Since other pdo_dblib users
have asked for a solution, I wanted to work out a non-hackish solution that
could make it into master. Since these column types are part of SQL-92 and
the issue could also affect pdo_mysql, I wanted to make it a generic
solution.

I'm admittedly less familiar with MySQL than MSSQL, but this blog post has
some examples of implicit casts affecting performance:
http://code.openark.org/blog/mysql/beware-of-implicit-casting

Could you share more details around why you think this change is
irrelevant/unimportant? Or let me know how I should document things better
in the RFC?

Thanks,
Adam

--001a114051263c8cb9054a119154--