Friday, April 24, 2015

SQL Relay 0.59 is out

SQL Relay version 0.59 is now available!

Significant New Features

There are a few...

Improved Support for Windows

This is the main new feature in this release.

Support for Ruby and TCL have been added. Now, on Windows, you can develop in C, C++, any .NET-supported language, Java, Perl, Python, PHP, Ruby and TCL.

Support for many additional databases has been added. SQL Relay can now be run on Windows, against Oracle, Sybase/SAP, DB2, Firebird, Postgresql, Mysql and ODBC-supported databases. The query router is also supported now too.

Performance isn't as good on Windows as it is on Unix/Linux yet, but it works and it appears to be stable.

On the development side, the build process has been completely refactored to use nmake and now supports a wide variety of versions of Visual Studio. It has been tested with VS2005, 2008, 2010, 2012 and 2013. VS6 and VS5 mostly work, but not entirely, yet. The build takes infinitely less time and it's now possible to fix something and nmake and nmake install from within the directory of the modified file, like one would be accustomed to on Unix/Linux. The Windows build process isn't yet as capable as the Unix/Linux build process, but it is greatly improved. See Installation on Windows for more information.

ODBC Improvements

Arguably this falls under Improved Support for Windows, but technically some of these improvements apply to UnixODBC/iODBC as well.

ODBC has long worked on Windows, but configuring it required manual modifications to the registry. No longer! The ODBC driver manager dialog exists now. On Windows, it should now be as easy to configure an ODBC connection to SQL Relay as it is to any other database.

The driver supports getting and setting many more attributes, and SQLTables works now. This enables many, many more ODBC applications to work with SQL Relay. It's been tested against a long list of apps with good success. If you've had trouble with it in the past, try this version.

MySQL Improvements

The MySQL database connection configuration now supports the maxselectlistsize and maxitembuffersize parameters, similar to Oracle, Sybase, DB2 and ODBC. This enables tuning of memory usage at runtime. See Tuning SQL Relay - Memory Usage for details.

LOB support is much improved with MySQL now too. In the past, the maximum number of bytes that could be fetched from a LOB column was limited by a macro in the source code - the same macro that defined the maximum size of a non-lob column. LOB's are now fetched in chunks and the amount of data that can be fetched is unlimited.

Support for Mono

SQL Relay has long had a C# API and ADO.NET driver, but they were classically only supported on Windows. These API's now work on Unix and Linux platforms as well, using Mono.

Less Significant, But Still Interesting New Features

The number of bind variables per-query was originally limited by a macro in the source code. Now, on the client-side, the number of bind variables is unlimited. Well, it's only limited by memory. On the server side, there's a new maxbindvars parameter in the sqlrelay.conf file that can be used to limit the number of bind variables that the server will accept. maxbindvars defaults to 256, but if you have an application that needs to send 1000 bind variables, you can just set it to 1000.

Login warnings are now printed on the screen, but not interpreted as errors. For example, if the database password is going to expire soon, but hasn't yet expired, the warning is displayed, but no longer interpreted as an error.

The sqlrsh command line client now supports the "cache" and "opencache" commands to cache result sets to a file and fetch result sets from a file. Not sure how many people actually use that feature, but sqlrsh supports fiddling with it now.

The logger modules have an enabled parameter which can be set to "yes" or "no". It's no longer necessary to comment out or remove the logger configuration to disable logging, you can just set enabled="no". See Logger Modules for more information.

Firebird recently added support for global temporary tables. Their implementation is very similar to Oracle's. SQL Relay now manages global temporary tables identically for Oracle and Firebird. There is even a droptemptables parameter in the Firebird connection configuration, analogous to the same parameter for Oracle.

In fact, support for global temporary tables has been generally improved. In the past, tables created during the current SQL Relay session were tracked and truncated at the end of the session, but global temporary tables created during previous runs of SQL Relay or outside of SQL Relay altogether were ignored, leading to those global temporary tables not being truncated at the end of the session. The Oracle and Firebird connections now support a globaltemptables parameter that can be set to a list of tables that should be truncated at the end of each session, or to "%", which causes SQL Relay to query the database for the list of global temp tables to truncate.

The Ruby DBI driver has been retired. I guess that's not a new feature, but it's something that was done in this release. Ruby DBI seems to have fallen out of favor and the driver was becoming increasingly difficult to maintain.

Tweaks and Fixes

Lots of small things have been tweaked, fixed, or improved as well

  • Binding a NULL to an integer works with db2 now.
  • Added a semaphore to ensure that the listener doesn't hand off the client to the connection until the connection is ready, eliminating a race condition on the handoff socket that could occur if the connection timed out waiting for the listener just after the listener had decided to use that connection.
  • Oracle temp tables that need to be truncated at the end of the session are truncated with "truncate table xxx" now rather than "delete from xxx".
  • Oracle temp tables that need to be dropped at the end of the session are truncated first, rather than the connection re-logging in.
  • An ora-14452 error (basically indicating that a temp table can only be dropped after being truncated, or if the current session ends) does not automatically trigger a re-login any more.
  • Updated cachemanager to use directory::read() directly instead of directory::getChildName(index).
  • Made cache ttl a 64-bit number.
  • Updated odbc connection code to use new/delete and rudiments methods rather than malloc/free and native calls.
  • Fixed command line client crash when using -id "instance" with an instance that uses authtier="database".
  • Fixed bugs that could make reexecuted db2 selects fail and cause a database re-login loop.
  • Tweaked spec file to remove empty directories on uninstall.
  • Fixed typo that could sometimes cause a listener crash.
  • Postgresql and MDBTools return error code of 1 rather than 0 for all errors now.
  • Fixed bugs related to autocommit with db's that support transaction blocks.
  • Fixed various bugs in sqlrconfigfile that caused sqlr-start with no -id to crash or behave strangely sometimes.
  • Updated the slow query logger to show the date/time that the query was executed.
  • Consolidated c, c++ and server source/includes down a few levels.
  • Fixed a misspelling in sqlrelay.dtd.
  • Swapped order of init directory detection, looking for /etc/init.d ahead of /etc/rc.d/init.d to resolve conflict with dkms on SuSE Enterprise.
  • sqlr-start spawns a new window on Windows now.
  • updated mysql connection to allow mysql_init to allocate a mysql struct on platforms that support mysql_init, rather than using a static struct.
  • Fixed subtle noon/midnight-related bugs in date/time translation.
  • Updated mysql connection to get affected rows when not using the statement api.
  • Updated mysql connection not to use the statement API on windows, for now.
  • Disabled mysql_change_user, for now.
  • Fixed blob-input binds on firebird.

Give it a try, report any issues!

Rudiments 0.50 is out

Rudiments 0.50 is now available!

The most significant feature in this release is a refactored, extent-based implementation of the variablebuffer and stringbuffer classes. The original implementation was crude, sufficient for storing fairly short strings, small in code size, but scaled poorly. The new implementation scales well while the code size still remains small.

There are also new dynamicarray and staticarray classes. Dynamicarray implements an array that expands as needed. It's also extent-based and scales well. Staticarry is just a thin wrapper around a C array. It only exists because you might want a dynamicarray who's members are static arrays, and there's no good way to do that in C++ without a wrapper. Or, at least none that I'm aware of.

This release also includes improved support for Windows and various other odd platforms, as well as various tweaks and fixes.

Full ChangeLog follows:

0.50 - added dictionary::detach and dictionary::getValue(key)
        added xmldom::getNullNode()
        improved xml printing for text nodes
        signalmanager::waitForSignal(NULL) works as expected now
        updated charstring::httpEscape not to escape legal symbols
        added flush() method to stdio classes
        added detection and support for vsnprintf_s
        fixed serviceentry, protocolentry and rpcentry on windows
        updated *entry classes for NULL and uninitialization safety
        implemented filesystem::initialize(fd) for Windows
        updated filesystem::initialize() with NULL and -1 to behave in
                predictable ways now, updated documentation for them too
        abstracted _get_osfhandle calls and added an invalid parameter callback
        updated filedescriptor to use bit fields for all of its flags
        implemented file::changeOwner() for windows
        removed xattrs stuff
        removed SSL-related ifdef's from headers and implemented degenerate
                SSL routines for when SSL isn't supported
        timezone conversion works on windows now
        refactored bytebuffer and stringbuffer to be extent-based
        fixed a subtle stringbuffer with initialcontents bug
        refactored stringbuffer to use bytebuffer::write/appendFormatted
                directly instead of charstring::parseNumber
        implemented dynamicarray and staticarray classes
        refactored build process to use nmake and be compatible with many
                different versions of MS Visual Studio
        updated vsnprintf_s calls for platforms where it's not defined
        added configure test for bool and true/false and definitions for
                platforms that don't define them
        updated timed semaphore waits - if seconds or nanoseconds are negative
                then the timed wait acts like an un-timed wait
        added support for getsockopt with size_t optlen parameter
        fixed strncasecmp on windows when str2 is longer than str1
        xmlsax uses memorymap on Windows now
        fixed file::lockFile() and file::unlockFile() on Windows
        fixed charstring::printf on Solaris 2.5.1
        fixed datetime::getSystemDateAndTime() for Windows without 64-bit
        fixed potential double-CloseHandle in thread class

Wednesday, April 1, 2015

SQL Relay 0.58.1 is out

It appears that 0.58 shipped with a bug that caused a few people to scratch their heads for quite a while.

The bug caused sqlr-start to crash, sometimes, under very specific circumstances.

The first is if an instance is defined with no port and no socket (ie. falling back to the default port of 9000). This would fairly reliably crash.

The second is very intermittent. Basically, if you call sqlr-start by itself, with no id, expecting that it will start all instances where enabled="yes" is configured, it will crash. Sometimes. Depending on a lot of random things. It turned out that a few variables were uninitialized, and random crashing a fairly classic behavior in that case.

Both issues are fixed in the 0.58.1 release. So, if you've had problems like those with 0.58, then give 0.58.1 a try.

It can be downloaded here.