Re: JDBC Support for standard_conforming_strings

Another message that did not reach the list because of large patches.
I've put the patches here:

http://www.ejurka.com/pgsql/patches/standard-strings/

Kris Jurka

Michael Paesold wrote:
> Here is a new version of my patch (set) implementing support for
> standard_conforming_strings.
>
> There are three patches now, split for easier review:
> 01-standard-strings.patch:
> the main patch (to be applied first)
> 02-metadata-escapes.patch:
> updates literal \\ escapes in AbstractJdbc2DatabaseMetaData
> 03-testsuite-escapes.patch:
> updates literal \\ escapes in the test-suite and expands the
> test for string literals for server versions >= 8.2.
>
> With all three patches applied, the driver passes the test suite against
> an 8.2 server with both standard_conforming_strings turned on or off, as
> well as connecting using the V2 or V3 protocol.
>
> Some notes:
> - The AbstractJdbc2DatabaseMetaData class made a lot of use of "x LIKE
> 'pg\\\\_%'" constructs. With standard_conforming_strings turned off,
> this must be written as 'pg\\_%'. Since many of the instances are in
> static initialization context, there is no access to that setting,
> though. So I changed all of those to "x ~ '^pg_'" (or similar) instead,
> which works without escaping. Tom Lane recommended this usage pattern
> for the information_schema on hackers, once. So I guess it should be OK
> for the JDBC driver, too.
> Nevertheless, the changes should be reviewed thoroughly, because some
> code paths are only executed for older version of Postgres.
>
> - The query splitting code now also supports parsing the escaped string
> syntax (E''). The parsing code in parseSql and modifyJdbcCall does not
> yet. I thought this was of less importance.
> Perhaps it could be done more easily by reusing or combining the main
> parsing code (the code already has comments suggesting that). Since the
> release of 8.2 is imminent, I would prefer to leave it as-is for now and
> rather get testing on the more important parts.
>
> - The V2 query path now uses the E'' escape string syntax for string
> constants as soon as a server version >= 8.2 is discovered. This
> protects the driver from changes to standard_conforming_strings, which
> it cannot detect using the V2 protocol. The escape string syntax is also
> used to send bytea data to the server.
>
> I am currently not aware of any other issues. Comments are welcome,
> testing is appreciated.
>
> Best Regards
> Michael Paesold
>