From bc6fb5436fa423aebb8616b1eb7d55d2c09d6300 Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Fri, 9 Feb 2007 03:43:22 +0000 Subject: Update FAQ for new 24-byte header, down from 28. --- doc/src/FAQ/FAQ.html | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'doc/src') diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html index fdcced96bf9..61e386aa3de 100644 --- a/doc/src/FAQ/FAQ.html +++ b/doc/src/FAQ/FAQ.html @@ -10,7 +10,7 @@ alink="#0000ff">
Last updated: Tue Feb 6 22:16:17 EST 2007
+Last updated: Thu Feb 8 22:43:13 EST 2007
Current maintainer: Bruce Momjian (bruce@momjian.us) @@ -720,25 +720,25 @@ table?
- 28 bytes: each row header (approximate) + 24 bytes: each row header (approximate) 24 bytes: one int field and one text field + 4 bytes: pointer on page to tuple ---------------------------------------- - 56 bytes per row + 52 bytes per row The data page size in PostgreSQL is 8192 bytes (8 KB), so: 8192 bytes per page - ------------------- = 146 rows per database page (rounded down) - 56 bytes per row + ------------------- = 158 rows per database page (rounded down) + 52 bytes per row 100000 data rows - -------------------- = 685 database pages (rounded up) - 146 rows per page + -------------------- = 633 database pages (rounded up) + 158 rows per page -685 database pages * 8192 bytes per page = 5,611,520 bytes (5.6 MB) +633 database pages * 8192 bytes per page = 5,185,536 bytes (5.2 MB)
Indexes do not require as much overhead, but do contain the data -- cgit v1.2.3