Only superusers can change this setting.įor clients using extended query protocol, durations of the Parse,īind, and Execute steps are logged independently. But it's a little heavy-handed as you have to be superuser, have to adjust the server configuration, cannot just target the execution of a single query, and you have to read the server logs (unless you redirect to stdout).Ĭauses the duration of every completed statement to be logged. This has probably the least overhead per measurement and produces the least distorted timings. This can be a negligible difference or huge depending on connection and volume of returned data. Important difference: psql measures on the client using local time from the local OS, so the time includes network latency. Second are also shown in minutes:seconds format, with hours and days The display is in milliseconds intervals longer than 1 Without a parameter, toggles the display between onĪnd off. With a parameter, turns displaying of how long each SQL statement But EXPLAIN adds some overhead to also output the query plan. ĮXPLAIN ANALYZE measures on the server, using server time from the server OS, excluding network latency. When node-level timing is turned off with this option. Run time of the entire statement is always measured, even Parameter to FALSE when only actual row counts, and not exact times,Īre needed. Query significantly on some systems, so it may be useful to set this The overhead of repeatedly reading the system clock can slow down the Include actual startup time and time spent in each node in the output. While mainly interested in total execution time, make it: EXPLAIN (ANALYZE, COSTS OFF, TIMING OFF) Several options are available to adjust the level of detail. JOIN died_on d1 USING (name) - name must be unique!Įxecute a couple of times to get more comparable times with warm cache. To check whether my adapted version of your query is, in fact, faster: EXPLAIN ANALYZE EXPLAIN ANALYZE not working with ALTER TABLE.Works for all DDL commands and some others. The query is actually executed (with all side -effect, if any!). You can prepend EXPLAIN ANALYZE, which reports the whole query plan with estimated costs actually measured times. I.e., measuring itself may distort the result. But whatever you do, some degree of the observer effect applies. There are various ways to measure execution time, each has pros and cons.
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