I saw a post on profiling memory usage today and this reminds me of several discussions I have had with different people.

Why would you want to profile the memory usage? Usually to see where memory is allocated and for what purposes, and usually you only care when memory usage is higher than expected. That is a DBA normally wants to use all available memory on a server for mysqld, whatever that size may be.

Configuration parameters may be inappropriate and need adjusting, so having a way to determine the range of memory usage based on those parameters would be most helpful.  However, the configuration parameters as a whole put no limit on memory used, so different workloads can quite easily lead to memory being insufficient on the OS, triggering swapping or perhaps the …

While Oracle deserves some praise for its donation of OpenOffice.org code to the Apache Foundation, it is disappointing again to see a legitimate open source market contender that has been marginalized by miscommunication and mismanagement of the project by a large vendor.

OpenOffice.org, warts and all, was probably the most significant competition for Microsoft Office for years and in many ways demonstrated the advantages of open source, helping usher in wider use of it, as well as greater usability. OO.o was in fact my reason for originally investigating and moving to open source software more than a decade ago. Regardless of past mismanagement of community and technology, that competitive factor has been diminished greatly since Oracle took ownership of OO.o. Now, after prompting a fork — as has …

UPDATE: The final vote is in and a winner has been declared, with Matt Asay and his arguments for the GPL taking the prize. You can see the debate or follow links to the other judges’ votes and thoughts here.

This is my assessment as a judge of the recent open source license debate held by the FOSS Learning Centre. We’ll have to begin with some qualifications and definitions, starting with the fact that there is no ‘best’ open source software license. Still, a star-studded open source software panel provided a lively, informative debate on the merits of some top open source licenses. For that, I congratulate and thank the panelists, Mike Milinkovich from the Eclipse Foundation arguing for the Eclipse Public License, Matt Asay of Alfresco arguing in favor of the GPL and David Maxwell from Coverity arguing for …

Before I get into details here is the bottom line. If you start MySQL on Solaris as a non-root (ie, mysql) user and for some reason you need to adjust the file descriptor resource limit for the parent shell, never use 'ulimit -n'. This will set both the soft and hard limit and may cause MySQL to adjust the max_connections and table_open_cache configuration variables upon next startup.

Use either:

 ulimit -S -n 1024

or something like:

prctl -n process.max-file-descriptor -t basic -v  1024 -r -i process $$

The Details

The default 'basic' privilege value for the resource control process.max-file-descriptor is 256. This control represents the soft ulimit for file descriptors per process. The default 'privileged' privilege is set to 65535, which represents the hard ulimit. A non-root user can adjust the soft limit down or up to the hard limit. Unless it has PRIV_SYS_RESOURCE a …

Before I get into details here is the bottom line. If you start MySQL on Solaris as a non-root (ie, mysql) user and for some reason you need to adjust the file descriptor resource limit for the parent shell, never use 'ulimit -n'. This will set both the soft and hard limit and may cause MySQL to adjust the max_connections and table_open_cache configuration variables upon next startup.

Use either:

 ulimit -S -n 1024

or something like:

prctl -n process.max-file-descriptor -t basic -v  1024 -r -i process $$

The Details

The default 'basic' privilege value for the resource control process.max-file-descriptor is 256. This control represents the soft ulimit for file descriptors per process. The default 'privileged' privilege is set to 65535, which represents the hard ulimit. A non-root user can adjust the soft limit down or up to the hard limit. Unless it has PRIV_SYS_RESOURCE a …

Before I get into details here is the bottom line. If you start MySQL on Solaris as a non-root (ie, mysql) user and for some reason you need to adjust the file descriptor resource limit for the parent shell, never use 'ulimit -n'. This will set both the soft and hard limit and may cause MySQL to adjust the max_connections and table_open_cache configuration variables upon next startup.

Use either:

 ulimit -S -n 1024

or something like:

prctl -n process.max-file-descriptor -t basic -v  1024 -r -i process $$

The Details

The default 'basic' privilege value for the resource control process.max-file-descriptor is 256. This control represents the soft ulimit for file descriptors per process. The default 'privileged' privilege is set to 65535, which represents the hard ulimit. A non-root user can adjust the soft limit down or up to the hard limit. Unless it has PRIV_SYS_RESOURCE a …