Mladen Gogala wrote:
With all due respect, I don't see how does the issue of hints fall into this category? As I explained, the mechanisms are already there, they're just not elegant enough.
You're making some assumptions about what a more elegant mechanism would look to develop that are simplifying the actual situation here. If you take a survey of everyone who ever works on this area of the code, and responses to this thread are already approaching a significant percentage of such people, you'll discover that doing what you want is more difficult--and very much "not elegant enough" from the perspective of the code involved--than you think it would be.
It's actually kind of funny...I've run into more than one person who charged into the PostgreSQL source code with the goal of "I'm going to add good hinting!" But it seems like the minute anyone gets enough understanding of how it fits together to actually do that, they realize there are just plain better things to be done in there instead. I used to be in the same situation you're in--thinking that all it would take is a better UI for tweaking the existing parameters. But now that I've actually done such tweaking for long enough to get a feel for what's really wrong with the underlying assumptions, I can name 3 better uses of development resources that I'd rather work on instead. I mentioned incorporating cache visibility already, Robert has talked about improvements to the sensitivity estimates, and the third one is improving pooling of work_mem so individual clients can get more of it safely.
Well, those two databases are also used much more widely than Postgres, which means that they're doing something better than Postgres.
"Starting earlier" is the only "better" here. Obviously Oracle got a much earlier start than either open-source database. The real divergence in MySQL adoption relative to PostgreSQL was when they released a Windows port in January of 1998. PostgreSQL didn't really match that with a fully native port until January of 2005.
Check out http://www.indeed.com/jobtrends?q=postgres%2C+mysql%2C+oracle&relative=1&relative=1 if you want to see the real story here. Oracle has a large installed base, but it's considered a troublesome legacy product being replaced whenever possible now in every place I visit. Obviously my view of the world as seen through my client feedback is skewed a bit toward PostgreSQL adoption. But you would be hard pressed to support any view that suggests Oracle usage is anything other than flat or decreasing at this point. When usage of one product is growing at an expontential rate and the other is not growing at all, eventually the market share curves always cross too.
-- Greg Smith 2ndQuadrant US greg@xxxxxxxxxxxxxxx Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us "PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
