|
|
|
|
pgstattuple README 2002/08/29 Tatsuo Ishii
|
|
|
|
|
|
|
|
|
|
1. Functions supported:
|
|
|
|
|
|
|
|
|
|
pgstattuple
|
|
|
|
|
-----------
|
|
|
|
|
pgstattuple() returns the relation length, percentage of the "dead"
|
|
|
|
|
tuples of a relation and other info. This may help users to determine
|
|
|
|
|
whether vacuum is necessary or not. Here is an example session:
|
|
|
|
|
|
|
|
|
|
test=> \x
|
|
|
|
|
Expanded display is on.
|
|
|
|
|
test=> SELECT * FROM pgstattuple('pg_catalog.pg_proc');
|
|
|
|
|
-[ RECORD 1 ]------+-------
|
|
|
|
|
table_len | 458752
|
|
|
|
|
tuple_count | 1470
|
|
|
|
|
tuple_len | 438896
|
|
|
|
|
tuple_percent | 95.67
|
|
|
|
|
dead_tuple_count | 11
|
|
|
|
|
dead_tuple_len | 3157
|
|
|
|
|
dead_tuple_percent | 0.69
|
|
|
|
|
free_space | 8932
|
|
|
|
|
free_percent | 1.95
|
|
|
|
|
|
|
|
|
|
Here are explanations for each column:
|
|
|
|
|
|
|
|
|
|
table_len -- physical relation length in bytes
|
|
|
|
|
tuple_count -- number of live tuples
|
|
|
|
|
tuple_len -- total tuples length in bytes
|
|
|
|
|
tuple_percent -- live tuples in %
|
|
|
|
|
dead_tuple_len -- total dead tuples length in bytes
|
|
|
|
|
dead_tuple_percent -- dead tuples in %
|
|
|
|
|
free_space -- free space in bytes
|
|
|
|
|
free_percent -- free space in %
|
|
|
|
|
|
|
|
|
|
pg_relpages
|
|
|
|
|
-----------
|
|
|
|
|
pg_relpages() returns the number of pages in the relation.
|
|
|
|
|
|
|
|
|
|
pgstatindex
|
|
|
|
|
-----------
|
|
|
|
|
pgstatindex() returns an array showing the information about an index:
|
|
|
|
|
|
|
|
|
|
test=> \x
|
|
|
|
|
Expanded display is on.
|
|
|
|
|
test=> SELECT * FROM pgstatindex('pg_cast_oid_index');
|
|
|
|
|
-[ RECORD 1 ]------+------
|
|
|
|
|
version | 2
|
|
|
|
|
tree_level | 0
|
|
|
|
|
index_size | 8192
|
|
|
|
|
root_block_no | 1
|
|
|
|
|
internal_pages | 0
|
|
|
|
|
leaf_pages | 1
|
|
|
|
|
empty_pages | 0
|
|
|
|
|
deleted_pages | 0
|
|
|
|
|
avg_leaf_density | 50.27
|
|
|
|
|
leaf_fragmentation | 0
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2. Installing pgstattuple
|
|
|
|
|
|
|
|
|
|
$ make
|
|
|
|
|
$ make install
|
|
|
|
|
$ psql -e -f /usr/local/pgsql/share/contrib/pgstattuple.sql test
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
3. Using pgstattuple
|
|
|
|
|
|
|
|
|
|
pgstattuple may be called as a relation function and is
|
|
|
|
|
defined as follows:
|
|
|
|
|
|
|
|
|
|
CREATE OR REPLACE FUNCTION pgstattuple(text) RETURNS pgstattuple_type
|
|
|
|
|
AS 'MODULE_PATHNAME', 'pgstattuple'
|
|
|
|
|
LANGUAGE C STRICT;
|
|
|
|
|
|
|
|
|
|
CREATE OR REPLACE FUNCTION pgstattuple(oid) RETURNS pgstattuple_type
|
|
|
|
|
AS 'MODULE_PATHNAME', 'pgstattuplebyid'
|
|
|
|
|
LANGUAGE C STRICT;
|
|
|
|
|
|
|
|
|
|
The argument is the relation name (optionally it may be qualified)
|
|
|
|
|
or the OID of the relation. Note that pgstattuple only returns
|
|
|
|
|
one row.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
4. Notes
|
|
|
|
|
|
|
|
|
|
pgstattuple acquires only a read lock on the relation. So concurrent
|
|
|
|
|
update may affect the result.
|
|
|
|
|
|
|
|
|
|
pgstattuple judges a tuple is "dead" if HeapTupleSatisfiesNow()
|
|
|
|
|
returns false.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
5. History
|
|
|
|
|
|
|
|
|
|
2007/05/17
|
|
|
|
|
|
|
|
|
|
Moved page-level functions to contrib/pageinspect.
|
|
|
|
|
|
|
|
|
|
2006/06/28
|
|
|
|
|
|
|
|
|
|
Extended to work against indexes.
|
