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| -rw-r--r-- | doc/FAQ | 14 | ||||
| -rw-r--r-- | doc/src/FAQ/FAQ.html | 14 |
2 files changed, 14 insertions, 14 deletions
@@ -1,7 +1,7 @@ Frequently Asked Questions (FAQ) for PostgreSQL - Last updated: Mon Jul 19 16:28:37 EDT 2004 + Last updated: Mon Jul 26 23:27:08 EDT 2004 Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) @@ -735,23 +735,23 @@ twenty bytes in length. The flat file would be 2.8 MB. The size of the PostgreSQL database file containing this data can be estimated as 6.4 MB: - 36 bytes: each row header (approximate) + 32 bytes: each row header (approximate) 24 bytes: one int field and one text field + 4 bytes: pointer on page to tuple ---------------------------------------- - 64 bytes per row + 60 bytes per row The data page size in PostgreSQL is 8192 bytes (8 KB), so: 8192 bytes per page - ------------------- = 128 rows per database page (rounded down) - 64 bytes per row + ------------------- = 136 rows per database page (rounded down) + 60 bytes per row 100000 data rows - -------------------- = 782 database pages (rounded up) + -------------------- = 735 database pages (rounded up) 128 rows per page -782 database pages * 8192 bytes per page = 6,406,144 bytes (6.4 MB) +735 database pages * 8192 bytes per page = 6,021,120 bytes (6 MB) Indexes do not require as much overhead, but do contain the data that is being indexed, so they can be large also. diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html index c3e305c4255..2272703f3c5 100644 --- a/doc/src/FAQ/FAQ.html +++ b/doc/src/FAQ/FAQ.html @@ -10,7 +10,7 @@ alink="#0000ff"> <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1> - <P>Last updated: Mon Jul 19 16:28:37 EDT 2004</P> + <P>Last updated: Mon Jul 26 23:27:08 EDT 2004</P> <P>Current maintainer: Bruce Momjian (<A href= "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> @@ -927,23 +927,23 @@ The size of the PostgreSQL database file containing this data can be estimated as 6.4 MB:</P> <PRE> - 36 bytes: each row header (approximate) + 32 bytes: each row header (approximate) 24 bytes: one int field and one text field + 4 bytes: pointer on page to tuple ---------------------------------------- - 64 bytes per row + 60 bytes per row The data page size in PostgreSQL is 8192 bytes (8 KB), so: 8192 bytes per page - ------------------- = 128 rows per database page (rounded down) - 64 bytes per row + ------------------- = 136 rows per database page (rounded down) + 60 bytes per row 100000 data rows - -------------------- = 782 database pages (rounded up) + -------------------- = 735 database pages (rounded up) 128 rows per page -782 database pages * 8192 bytes per page = 6,406,144 bytes (6.4 MB) +735 database pages * 8192 bytes per page = 6,021,120 bytes (6 MB) </PRE> <P>Indexes do not require as much overhead, but do contain the data |