Re: Re: [RFC] Extended String Types For PDO
| From: | Adam Baratz | Date: | Mon, 06 Mar 2017 15:29:54 +0000 |
| Subject: | Re: Re: [RFC] Extended String Types For PDO | ||
| References: | 1 2 3 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-98409@lists.php.net to get a copy of this message | ||
>
> 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