That's some great starting advice there. I have a couple of final exams in the next 36 hours. Will get to work almost immediately after that. I will definitely take small steps before going for some of the tougher tasks. I would of-course like this conversation to go on, so I can see a more comprehensive TODO list. One of my first tasks on GSoC is to make sure I create a good project specification document. So there can be definite expectations and targets. This conversation helps me do that! Regards, Shiv
On Thu, Apr 28, 2011 at 9:50 AM, Greg Smith <g...@2ndquadrant.com> wrote: > Shiv wrote: > >> On the program I hope to learn as much about professional software >> engineering principles as PostgreSQL. My project is aimed towards extending >> and hopefully improving upon pgtune. If any of you have some ideas or >> thoughts to share. I am all ears!! >> > > Well, first step on the software engineering side is to get a copy of the > code in a form you can modify. I'd recommend grabbing it from > https://github.com/gregs1104/pgtune ; while there is a copy of the program > on git.postgresql.org, it's easier to work with the one on github instead. > I can push updates over to the copy on postgresql.org easily enough, and > that way you don't have to worry about getting an account on that server. > > There's a long list of suggested improvements to make at > https://github.com/gregs1104/pgtune/blob/master/TODO > > Where I would recommend getting started is doing some of the small items on > there, some of which I have already put comments into the code about but > just not finished yet. Some examples: > > -Validate against min/max > -Show original value in output > -Limit shared memory use on Windows (see notes on shared_buffers at > http://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server for more > information) > -Look for postgresql.conf file using PGDATA environment variable > -Look for settings files based on path of the pgtune executable > -Save a settings reference files for newer versions of PostgreSQL (right > now I only target 8.4) and allow passing in the version you're configuring. > > A common mistake made by GSOC students is to dive right in to trying to > make big changes. You'll be more successful if you get practice at things > like preparing and sharing patches on smaller changes first. > > At the next level, there are a few larger features that I would consider > valuable that are not really addressed by the program yet: > > -Estimate how much shared memory is used by the combination of settings. > See Table 17-2 at > http://www.postgresql.org/docs/9.0/static/kernel-resources.html ; those > numbers aren't perfect, and improving that table is its own useful project. > But it gives an idea how they fit together. I have some notes at the end > of the TODO file on how I think the information needed to produce this needs > to be passed around the inside of pgtune. > > -Use that estimate to produce a sysctl.conf file for one platform; Linux is > the easiest one to start with. I've attached a prototype showing how to do > that, written in bash. > > -Write a Python-TK or web-based front-end for the program. > > Now that I know someone is going to work on this program again, I'll see > what I can do to clean some parts of it up. There are a couple of things > it's easier for me to just fix rather than to describe, like the way I > really want to change how it adds comments to the settings it changes. > > -- > Greg Smith 2ndQuadrant US g...@2ndquadrant.com Baltimore, MD > PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us > > > > #!/bin/bash > > # Output lines suitable for sysctl configuration based > # on total amount of RAM on the system. The output > # will allow up to 50% of physical memory to be allocated > # into shared memory. > > # On Linux, you can use it as follows (as root): > # > # ./shmsetup >> /etc/sysctl.conf > # sysctl -p > > # Early FreeBSD versions do not support the sysconf interface > # used here. The exact version where this works hasn't > # been confirmed yet. > > page_size=`getconf PAGE_SIZE` > phys_pages=`getconf _PHYS_PAGES` > > if [ -z "$page_size" ]; then > echo Error: cannot determine page size > exit 1 > fi > > if [ -z "$phys_pages" ]; then > echo Error: cannot determine number of memory pages > exit 2 > fi > > shmall=`expr $phys_pages / 2` > shmmax=`expr $shmall \* $page_size` > > echo \# Maximum shared segment size in bytes > echo kernel.shmmax = $shmmax > echo \# Maximum number of shared memory segments in pages > echo kernel.shmall = $shmall > >
