Posted by Luke Davies on Sep 30, 2009
Recently I was looking into a long-running statement and noticed a curious thing. One moment, I had just over 4 billion buffer gets, and the next I had around 2 million.
The statement was still processing and the number of physical reads was still rising.
I think the reason for this is that the internal place holder for this value is simply a 32-bit unsigned integer that has the largest number of 4294967295. But my version of Oracle is 64-bit; I thought that maybe it would use 64-bit integers.
So, beware that if you have had a statement running for some time, you cannot necessarily rely on the buffer_gets column in v$sql—it may be that it has run over the limit, been recycled, and is counting from zero again.
The evidence. Read the rest of this entry . . .
Posted by Nicklas Westerlund on Oct 6, 2008
Yesterday evening, a friend of mine had some issues with installing DBD::mysql, and asked if I had encountered the same issue. The problem, as the output from make test showed, was that certain symbols was missing:
# Tried to use 'DBD::mysql'.
# Error: Can't load '/Users/westerlund/src/perl/DBD-mysql-4.008/blib/arch/auto/DBD/mysql/mysql.bundle' for module DBD::mysql: dlopen(/Users/westerlund/src/perl/DBD-mysql-4.008/blib/arch/auto/DBD/mysql/mysql.bundle, 2): Symbol not found: _is_prefix
Fair enough, this is related to a 64-bit issue with MySQL—at least with my Perl version, which is now:
Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
Platform:
osname=darwin, osvers=9.5.0, archname=darwin-thread-multi-64int-2level
If you try to link to a x86_64 version of MySQL, then you get the above mentioned error. So, I downloaded an x86 version of MySQL and tried again. The output from perl Makefile.PL:
cflags (mysql_config) = -I/Users/westerlund/src/perl/mysql-5.1.28-rc-osx10.5-x86/include -g -Os -arch i386 -fno-common -D_P1003_1B_VISIBLE -DSIGNAL_WITH_VIO_CLOSE -DSIGNALS_DONT_BREAK_READ -DIGNORE_SIGHUP_SIGQUIT -DDONT_DECLARE_CXA_PURE_VIRTUAL
embedded (mysql_config) =
libs (mysql_config) = -L/Users/westerlund/src/perl/mysql-5.1.28-rc-osx10.5-x86/lib -lmysqlclient -lz -lm -lmygcc
mysql_config (Users choice) = /Users/westerlund/src/perl/mysql-5.1.28-rc-osx10.5-x86/bin/mysql_config
That looks all good and nice, the right paths, versions and everything. So I compiled it OK, but when running make test again: Read the rest of this entry . . .
