Hi, On 2018-09-25 01:47:49 -0700, Andres Freund wrote: > Forcing parallelism and JIT to be on, I get: > > postgres[20216][1]=# EXPLAIN (ANALYZE, VERBOSE, BUFFERS) SELECT count(*) FROM > pg_class; > > Finalize Aggregate (cost=15.43..15.44 rows=1 width=8) (actual > time=183.282..183.282 rows=1 loops=1) > Output: count(*) > Buffers: shared hit=13 > -> Gather (cost=15.41..15.42 rows=2 width=8) (actual > time=152.835..152.904 rows=2 loops=1) > Output: (PARTIAL count(*)) > Workers Planned: 2 > Workers Launched: 2 > JIT for worker 0: > Functions: 2 > Options: Inlining true, Optimization true, Expressions true, > Deforming true > Timing: Generation 0.480 ms, Inlining 78.789 ms, Optimization 5.797 > ms, Emission 5.554 ms, Total 90.620 ms > JIT for worker 1: > Functions: 2 > Options: Inlining true, Optimization true, Expressions true, > Deforming true > Timing: Generation 0.475 ms, Inlining 78.632 ms, Optimization 5.954 > ms, Emission 5.900 ms, Total 90.962 ms > Buffers: shared hit=13 > -> Partial Aggregate (cost=15.41..15.42 rows=1 width=8) (actual > time=90.608..90.609 rows=1 loops=2) > Output: PARTIAL count(*) > Buffers: shared hit=13 > Worker 0: actual time=90.426..90.426 rows=1 loops=1 > Buffers: shared hit=7 > Worker 1: actual time=90.791..90.792 rows=1 loops=1 > Buffers: shared hit=6 > -> Parallel Seq Scan on pg_catalog.pg_class (cost=0.00..14.93 > rows=193 width=0) (actual time=0.006..0.048 rows=193 loops=2) > Output: relname, relnamespace, reltype, reloftype, > relowner, relam, relfilenode, reltablespace, relpages, reltuples, > relallvisible, reltoastrelid, relhasindex, relisshared, relpersistence, > relkind, relnatts, relchecks, relhasoids, relhasrules, relhastriggers, > relhassubclass, relrowsecurity, relfo > Buffers: shared hit=13 > Worker 0: actual time=0.006..0.047 rows=188 loops=1 > Buffers: shared hit=7 > Worker 1: actual time=0.006..0.048 rows=198 loops=1 > Buffers: shared hit=6 > Planning Time: 0.152 ms > JIT: > Functions: 4 > Options: Inlining true, Optimization true, Expressions true, Deforming true > Timing: Generation 0.955 ms, Inlining 157.422 ms, Optimization 11.751 ms, > Emission 11.454 ms, Total 181.582 ms > Execution Time: 184.197 ms
With parallelism on, this is the aggregated cost of doing JIT compilation. I wonder if, in VERBOSE mode, we should separately display the cost of JIT for the leader. Comments? - Andres
