Tuesday, October 28, 2014

oracle-jvm error...

I'm not sure how long ago this happened, but there are now lots of different JVM's available for Debian and Ubuntu systems: openjdk-6, openjdk-7, openjdk-8, oracle-jvm-7 and oracle-jvm-8. Possibly more...

SQL Relay 0.57 has no trouble detecting the openjdk's, but doesn't properly detect oracle-jvm's and the build fails. I ran into this error trying to build on a Raspberry PI running Raspbian, but a few people have reported the same error on Debian and Ubuntu sytems.

There are 3 workarounds:

Disable Java

If you're not using SQL Relay with java then you can add --disable-java to the configure command and SQL Relay won't even try to build against oracle-jvm.

Replace Oracle JVM with OpenJDK

This may be tricky. I'm not sure which packages have a hard dependency on oracle-jvm as opposed to just needing some version of Java. Your mileage may vary.

Patch the Configure Script

Edit the configure script in the SQL Relay source distribution and look for a line like:

   for i in `ls -d /usr/java/jdk* /usr/java/j2sdk* /usr/local/jdk* 2> /dev/null` /usr/java 
/usr/local/java `ls -d /usr/local/openjdk* /usr/pkg/java/openjdk* 2> /dev/null` `ls -d /usr/lib64/jvm/java 2> /dev/null` 
`ls -d /usr/lib64/jvm/java-1.8* 2> /dev/null` `ls -d /usr/lib64/jvm/java-1.7* 2> /dev/null` `ls -d /usr/lib64
/jvm/java-1.6* 2> /dev/null` `ls -d /usr/lib/jvm/java 2> /dev/null` `ls -d /usr/lib/jvm/java-1.8* 2> /dev/null` `ls -d 
/usr/lib/jvm/java-1.7* 2> /dev/null` `ls -d /usr/lib/jvm/java-1.6* 2> /dev/null` /System/Library/Frameworks
/JavaVM.framework/Versions/Current /usr /usr/local

and replace it with these lines:

   for i in `ls -d /usr/java/jdk* /usr/java/j2sdk* /usr/local/jdk* 2> /dev/null` \
    /usr/java \
    /usr/local/java \
    `ls -d /usr/local/openjdk* /usr/pkg/java/openjdk* 2> /dev/null` \
    `ls -d /usr/lib64/jvm/java 2> /dev/null` \
    `ls -d /usr/lib64/jvm/java-1.8* 2> /dev/null` \
    `ls -d /usr/lib64/jvm/java-1.7* 2> /dev/null` \
    `ls -d /usr/lib64/jvm/java-1.6* 2> /dev/null` \
    `ls -d /usr/lib64/jvm/jdk-7-* 2> /dev/null` \
    `ls -d /usr/lib64/jvm/jdk-8-* 2> /dev/null` \
    `ls -d /usr/lib/jvm/java 2> /dev/null` \
    `ls -d /usr/lib/jvm/java-1.8* 2> /dev/null` \
    `ls -d /usr/lib/jvm/java-1.7* 2> /dev/null` \
    `ls -d /usr/lib/jvm/java-1.6* 2> /dev/null` \
    `ls -d /usr/lib/jvm/jdk-7-* 2> /dev/null` \
    `ls -d /usr/lib/jvm/jdk-8-* 2> /dev/null` \
    /System/Library/Frameworks/JavaVM.framework/Versions/Current \
    /usr \

One of those three solutions should work.

The source has been updated and it's fixed in CVS. The next release will include the fix too.

Saturday, October 11, 2014


It appears that I forgot to run "make distclean" before building that last round of tar.gz and zip files for both Rudiments and SQL Relay. So, if you downloaded last week (the week of October 6th, 2014), or the week before, then you may have had trouble building. Configure probably ran, but make might not have made anything.

Who knows what platform the binaries that were in there ran on? Fedora 20 x64 maybe... Maybe not though.


I just updated the tar.gz and zip files with clean versions. I also downloaded and verified them this time. They ought to be correct.

Thanks Florin... If you hadn't pointed it out, I might never have noticed.

Saturday, October 4, 2014

SQL Relay - 0.57 is out

SQL Relay 0.57 is now available!

Windows Support

Support for Windows is much improved in this release. The command line clients all work now - sqlrsh, sqlr-export, sqlr-import, etc. The C/C++, C# and ADO.NET API's have worked for a while, but are now joined by native API's for Perl, Python, PHP and Java as well as drivers for Perl DBI, Python DB and PHP PDO.

It is possible to build all of this on Windows using MS Visual Studio or MS Visual Studio Express but it is currently quite difficult and requires specific versions of things to be installed in the right places. PHP is especially difficult to work with. In fact, I'm honestly not sure how 3rd party developers are expected to develop drivers for Windows. I had to shoehorn the headers in manually from the source code.

However... The SQL Relay Binary Distribution for Windows is now available (for a few bucks) and provides installers for binary versions of the above-mentioned software.

So... in addition to just accessing SQL Relay from command line clients, SQL Relay applications, including web-based applications, can now be developed for Windows in C, C++, C# (and other .NET languages), Perl, Python, PHP and Java.

Give it a try, let me know if you run into trouble.

Oracle "describe table" Improvements

In sqlrsh if you run "describe tablename" it returns info about the columns of the table - name, type, size, etc. This is accomplished by a call to the getColumnList() method of the C++ API. All SQL Relay API's support this method, and it has been improved.

For oracle tables, if a column is a primary, unique or foreign key, that information is now given. In previous releases it was not. This is a fairly expensive operation, as it turns out, so there is a config parameter to disable looking up keys. See disablekeylookup=yes/no in the oracle connection string in the SQL Relay Configuration Reference for more info.

Also, if you run "describe" on a synonym to a table in another schema, it will now return information about that table. In previous releases, only tables could be described.

Rudiments Improvements

The Rudiments library that SQL Relay depends on has been updated to randomize the list of hosts returned by DNS server when using round-robin DNS. If you are using round robin DNS to distribute SQL Relay clients over a pool of SQL Relay servers, then the behavior may different than in previous releases. In particular, if one host is down, then rather than slamming the next host in the list with all of the downed host's traffic, load will be distributed over the remaining hosts. This feature was added to work around an issue with many recent-ish implementations of getaddrinfo().

Rudiments has also been updated to support kqueue, epoll, port_create, /dev/poll, poll and select in its listener class. There should be no concerns now about large numbers of clients queuing up on the listener, or with listener performance with regard to using select internally.

See the rudiments release announcement for more information on these updates.

Bug Fixes and Minor Improvements

This release features a few bug fixes and minor improvements too.

The Python API's getRowDictionary method had a bug where None's were being returned as 0's when getNullsAsNones was set. That's fixed now.

Sensible errors are now returned when the format of a numeric bind variable is incorrect when using mysql, firebird or oracle. An error was fixed that could cause mysql connection to loop up if alphanumeric bind variable names were used instead of numbers. A bind-variable translation bug was fixed that could cause variables not to be translated when multiple formats are used in the same query and one of them is the correct format too.

The --with-system-libtool configure option was broken but it's fixed now.

Minix 3.3.0 is now supported. At least the client side is. Ie. you can access Oracle from Minix 3.3.0 using sqlrsh and SQL Relay running on another system. The server-side stuff doens't work yet. The Minix kernel doesn't support semaphores by default and Minix 3.3.0 ships without kernel source. I'm not sure if it supports semaphores at all though, so maybe that's moot.

The drop-in replacement library for MySQL had bugs with its implementations of mysql_row_seek() and mysql_row_tell(). Those are fixed now.

The configure script properly detects Maria DB on Ubuntu 14.04.1 now.

Give it a try and report any bugs that you find!

Friday, October 3, 2014

Rudiments - 0.48 is out

Rudiments 0.48 is now available!

This release has a few fairly important features.

Random Number Generation

The randomnumber class has been updated to support CryptGenRandom (on Windows), arc4random, random_r, rand_r, lrand48_r, random, rand and lrand48. It will use whichever of those it can find, in that order. The class has static and non-static members now. When the non-static members are used, the class can be seeded once and numbers (or scaled numbers) can be generated over and over without explicitly re-seeding.

Inet Socket Clients

Several improvements have been made to the inetsocketclient class.

Internally, inetsocketclient uses either getaddrinfo() or some variant of gethostbyname(), depending on what's available.

First, a bug was fixed that caused timeouts not to work on systems that don't have getaddrinfo().

Second, it seems that the behavior of getaddrinfo() has changed over the years and a workaround has been introduced to deal with some issues that the new behavior causes...

When round-robin DNS is used, gethostbyname() and getaddrinfo() fetch the entire list of IP addresses that the host name resolves to. The inetsocketclient's connect() method gets this list and tries to connect to each of these IP's, in the order that they were returned by gethostbyname()/getaddrinfo(). When round-robin DNS is used, the order of the IP's in the list is rotated with each DNS request. This can be used to implement a simple load-balancing scheme.

"Recent" (I'm not sure how recent) implementations of getaddrinfo() have begun sorting the IP's, defeating round-robin DNS entirely. Some implementations have a /etc/gai.conf file that allow a sortv4=no directive, but many do not. Some implementations randomize the list of IP's. Some implementations return them in the order that the DNS server returned them in.

Rudiments has no way of knowing what the behavior of getaddrinfo() is, so now, by default, the list of IP addresses is randomized. For the sake of consistency, it's randomized whether it uses getaddrinfo() internally or some variant of gethostbyname(). Methods have been added to the class to enable or disable this behavior too.

Randomization provides a benefit over round-robin DNS as well. With round-robin DNS, when a host goes down, the next host in the list will receive all of the downed host's traffic. With randomization, traffic is distributed evenly over the hosts that are still up.

listner class

The listener class has been refactored entirely to match the paradigms established by kqueue, epoll, /dev/poll, etc. It now supports kqueue, epoll, port_create, /dev/poll, poll and select internally as well, and will use whichever is available, in that order.

In the previous release, support was added for kqueue, epoll and poll but the implementation still did some inefficient things like rebuilding the list of file descriptors to listen on before each iteration. The list is only rebuilt if a file descriptor is added or removed now.

Minix 3.3.0

Minix 3.3.0 came out since the last release and it's now supported.

General Bug Fixes and Improvements

Some general bug fixes and improvements were implemented as well. Cygwin builds ought to work correctly now. Setting file permissions ought to work natively on Windows now too.