blob: 6a191e9cced316a92f532536d74b67f21cd34a81 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
pgstattuple README 2001/10/01 Tatsuo Ishii
1. What is pgstattuple?
pgstattuple returns the percentage of the "dead" tuples of a
table. This will help users to judge if vacuum is needed.
In addition, pgstattuple prints more detailed information using
NOTICE.
test=# select pgstattuple('tellers');
NOTICE: physical length: 0.08MB live tuples: 20 (0.00MB, 1.17%) dead tuples: 320 (0.01MB, 18.75%) free/reusable space: 0.01MB (18.06%) overhead: 62.02%
pgstattuple
-------------
18.75
(1 row)
Above example shows tellers table includes 18.75% dead tuples.
physical length physical size of the table in MB
live tuples information on the live tuples
dead tuples information on the dead tuples
free/reusable space available space
overhead overhead space
2. Installing pgstattuple
$ make
$ make install
$ psql -e -f /usr/local/pgsql/share/contrib/pgstattuple.sql test
3. Using pgstattuple
pgstattuple can be called as a function:
pgstattuple(NAME) RETURNS FLOAT8
The argument is the table name. pgstattuple returns the percentage
of the "dead" tuples of a table.
4. Notes
pgstattuple acquires only a read lock on the table. So concurrent
update may affect the result.
pgstattuple judges a tuple is "dead" if HeapTupleSatisfiesNow()
returns false.
|
