Re: [DOCS] Translate Postgresql FAQ into Chinese
gee, my last mail bounced back because the size of attachement. repost here: I've Just catch this thread. The attachement is a plain text version convert using firefox. Wish it could be add to the repository. It's a little bit old, but we've just build a PostgreSQL i18n Chinese team, so, I think we could update the FAQ with the main postgresql version. and we'll very happy if Mr. Zhou could help it. Thianks and regards laser postgresFAQ-zh_CN.txt.gz Description: Unix tar archive ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
[DOCS] Possible copy error in explain example
I was looking at: http://candle.pha.pa.us/main/writings/pgsql/sgml/performance-tips.html And noticed in the first example that it is claimed the cost estimate is 233 disk block reads. However, "233" doesn't appear in the explain output shown. I think that "233" is supposed to match the "333" in the explain output, but I am not 100% sure. ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
[DOCS] My oops (Was: possible copy error in explain docs)
I saw a comma as a period and missed that the page reads estimate was only part of the cost. So I was wrong and the example is correct. ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [DOCS] Possible copy error in explain example
On Mon, Apr 11, 2005 at 11:40:01PM -0500, Bruno Wolff III wrote: > I was looking at: > http://candle.pha.pa.us/main/writings/pgsql/sgml/performance-tips.html > > And noticed in the first example that it is claimed the cost estimate > is 233 disk block reads. However, "233" doesn't appear in the explain > output shown. I think that "233" is supposed to match the "333" in > the explain output, but I am not 100% sure. This part? This is about as straightforward as it gets. If you do SELECT * FROM pg_class WHERE relname = 'tenk1'; you will find out that tenk1 has 233 disk pages and 1 rows. So the cost is estimated at 233 page reads, defined as costing 1.0 apiece, plus 1 * cpu_tuple_cost which is currently 0.01 (try SHOW cpu_tuple_cost). Doesn't that work out to (233 * 1.0) + (1 * 0.01) = 233.0 + 100.0 = 333.0 or am I missing something? -- Michael Fuhr http://www.fuhr.org/~mfuhr/ ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [DOCS] Possible copy error in explain example
On Mon, Apr 11, 2005 at 22:34:21 -0600, Michael Fuhr <[EMAIL PROTECTED]> wrote: > On Mon, Apr 11, 2005 at 11:40:01PM -0500, Bruno Wolff III wrote: > > I was looking at: > > http://candle.pha.pa.us/main/writings/pgsql/sgml/performance-tips.html > > > > And noticed in the first example that it is claimed the cost estimate > > is 233 disk block reads. However, "233" doesn't appear in the explain > > output shown. I think that "233" is supposed to match the "333" in > > the explain output, but I am not 100% sure. > > This part? > > This is about as straightforward as it gets. If you do > > SELECT * FROM pg_class WHERE relname = 'tenk1'; > > you will find out that tenk1 has 233 disk pages and 1 rows. > So the cost is estimated at 233 page reads, defined as costing > 1.0 apiece, plus 1 * cpu_tuple_cost which is currently 0.01 > (try SHOW cpu_tuple_cost). > > Doesn't that work out to > > (233 * 1.0) + (1 * 0.01) = 233.0 + 100.0 = 333.0 > > or am I missing something? No, I was. I misread a comma as a period and when I scanned ahead to see if I could find something similar in other examples I missed the part where it added in the cpu cost. After I sent the message I looked some more and spotted what I missed. I didn't have a copy back yet of the original message, so my oops message wasn't threaded with the original. ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
