local machine vs. qa database execution timing

local-vs-remote-query-timing.md

Same query EXPLAIN plan run from my local machine vs. from shell on qa.iadops.com

My laptop:

oao_trial=> explain analyze insert into test values (7418880);
                                         QUERY PLAN
--------------------------------------------------------------------------------------------
 Insert on test  (cost=0.00..0.01 rows=1 width=0) (actual time=0.280..0.280 rows=0 loops=1)
   ->  Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.002..0.004 rows=1 loops=1)
 Planning time: 0.183 ms
 Execution time: 0.502 ms
(4 rows)

Time: 25.366 ms

On QA machine:

oao_trial=# explain analyze insert into test values (7418880);
                                         QUERY PLAN
--------------------------------------------------------------------------------------------
 Insert on test  (cost=0.00..0.01 rows=1 width=0) (actual time=0.055..0.055 rows=0 loops=1)
   ->  Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.002..0.004 rows=1 loops=1)
 Planning time: 0.026 ms
 Execution time: 0.086 ms
(4 rows)

Time: 1.433 ms

Note that "Execution time" is the query planner's record of actual time on server. The "Time:" line at the end of each is elapsed time as recorded client-side. The 24ms difference corresponds very closely to the avg latency between my laptop and qa as reported by mtr.