8 Monitoring

Source chapter 3.6 for PostgreSQL 10.

Beta 1Source pages: PDF 58-59Original PDF on GitHub

PDF page 58

3.6.1 Monitor wait events

Wait events that are shown in the wait_event_type and wait_event columns of the pg_stat_activity catalog have been added. LWLockNamed and LWLockTranche that were output in the wait_event_type column in PostgreSQL 9.6 have been renamed to LWLock.

wait_event_type	Description	Change
column
LWLockLockBufferPin	Light weight lock wait Lock wait Waiting for buffer	Renamed
Activity	Waiting for processing acceptance of background processes	Added
Client	A state in which the client is waiting for processing	Added
Extension	Wait for background worker	Added
IPC	A state waiting for processing from another process	Added
Timeout	Waiting for timeout	Added
IO	Waiting for I / O	Added

Table 23 Value to be output to the wait_event_type column

3.6.2 EXPLAIN SUMMARY statement

A SUMMARY clause has been added to the EXPLAIN statement to output only the execution plan generation time.

Example 60 EXPLAIN SUMMARY

postgres=> EXPLAIN (SUMMARY) SELECT * FROM data1 ;
                           QUERY PLAN
----------------------------------------------------------------
 Seq Scan on data1  (cost=0.00..15406.00 rows=1000000 width=11)
 Planning time: 0.072 ms
(2 rows)

3.6.3 VACUUM VERBOSE statement

Oldest xmin and frozen pages are now output as the output of the VACUUM VERBOSE statement.

PDF page 59

Example 61 Execute VACUUM VERBOSE statement

postgres=> VACUUM VERBOSE data1 ;
NFO:  vacuuming "public.data1"
…
DETAIL:  0 dead row versions cannot be removed yet, oldest xmin: 587
There were 0 unused item pointers.
Skipped 0 pages due to buffer pins, 0 frozen pages.
0 pages are entirely empty.
…