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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.