Re: [PERFORM] [PERFORMANCE] Insights: fseek OR read_cluster?

2011-09-27 Thread Antonio Rodriges
Thank you, Marti, Is there any comprehensive survey of (at least most, if not all) modern features of operating systems, for example I/O scheduling, extent-based filesytems, etc.? -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription:

[PERFORM] [PERFORMANCE] Insights: fseek OR read_cluster?

2011-09-26 Thread Antonio Rodriges
Hello, It is interesting how PostgreSQL reads the tablefiie. Whether its indexes store/use filesystem clusters locations containing required data (so it can issue a low level cluster read) or it just fseeks inside a file? Thank you -- Sent via pgsql-performance mailing list (pgsql-performance@p

Re: [PERFORM] [PERFORMANCE] Insights: fseek OR read_cluster?

2011-09-26 Thread Antonio Rodriges
Thank you, Craig, your answers are always insightful > What is read_cluster()  ? Are you talking about some kind of async and/or I meant that if you want to read a chunk of data from file you (1) might not call traditional fseek but rather memorize hard drive cluster numbers to boost disk seeks a

[PERFORM] [PERFORMANCE] Insights: fseek OR read_cluster?

2011-09-23 Thread Antonio Rodriges
Hello, It is interesting how PostgreSQL reads the tablefiie. Whether its indexes store/use filesystem clusters locations containing required data (so it can issue a low level cluster read) or it just fseeks inside a file? Thank you -- Sent via pgsql-performance mailing list (pgsql-performance@p

Re: [PERFORM] PostgreSQL insights: does it use DMA?

2011-09-10 Thread Antonio Rodriges
Thank you a lot, Craig, that's really insightful and exhaustively complete explanation I've expected! 2011/9/10 Craig Ringer : > On 10/09/2011 1:55 AM, Antonio Rodriges wrote: >> >> Hello, >> >> Does anyone know whether PostgreSQL uses DMA (Direct Memory A

Re: [PERFORM] PostgreSQL insights: does it use DMA?

2011-09-09 Thread Antonio Rodriges
http://www.ibm.com/developerworks/library/j-zerocopy/ 2011/9/9 Scott Marlowe : > On Fri, Sep 9, 2011 at 11:55 AM, Antonio Rodriges > wrote: >> Hello, >> >> Does anyone know whether PostgreSQL uses DMA (Direct Memory Access) in >> certain cases to improve networking I

[PERFORM] PostgreSQL insights: does it use DMA?

2011-09-09 Thread Antonio Rodriges
to devise the best logic for the system with PostgreSQL as a layer. Certainly I could study PostgreSQL sources or test it with a simple application but I hope PostgreSQL experts are aware of this feature. Thank you. -- Kind regards, Antonio Rodriges -- Sent via pgsql-performance mailin