I passed PROVE_FLAGS="--timer -v" to get the timings and run under --format=directory.
Without new test: ok 23400 ms ( 0.00 usr 0.00 sys + 2.84 cusr 1.53 csys = 4.37 CPU) ok 23409 ms ( 0.00 usr 0.01 sys + 2.81 cusr 1.53 csys = 4.35 CPU) With new test, under --format=directory: -j2 (parallel, default gzip compression) ok 27517 ms ( 0.00 usr 0.00 sys + 3.92 cusr 1.86 csys = 5.78 CPU) ok 27772 ms ( 0.01 usr 0.00 sys + 3.96 cusr 1.86 csys = 5.83 CPU) ok 27654 ms ( 0.00 usr 0.00 sys + 3.81 cusr 1.94 csys = 5.75 CPU) ok 27663 ms ( 0.00 usr 0.00 sys + 4.11 cusr 1.71 csys = 5.82 CPU) -j2 --compress=0 ok 27710 ms ( 0.00 usr 0.00 sys + 3.79 cusr 1.86 csys = 5.65 CPU) ok 27567 ms ( 0.01 usr 0.00 sys + 3.67 cusr 1.96 csys = 5.64 CPU) ok 27582 ms ( 0.00 usr 0.00 sys + 3.60 cusr 1.90 csys = 5.50 CPU) ok 27519 ms ( 0.01 usr 0.00 sys + 3.71 cusr 1.80 csys = 5.52 CPU) -j2 --compress=zstd ok 27240 ms ( 0.01 usr 0.00 sys + 3.65 cusr 2.10 csys = 5.76 CPU) ok 27301 ms ( 0.01 usr 0.00 sys + 3.77 cusr 1.97 csys = 5.75 CPU) -j2 --compress=zstd:1 ok 27695 ms ( 0.01 usr 0.00 sys + 3.66 cusr 2.05 csys = 5.72 CPU) ok 27671 ms ( 0.01 usr 0.00 sys + 3.76 cusr 1.95 csys = 5.72 CPU) --compress=zstd:1 (no parallelism) ok 28417 ms ( 0.01 usr 0.00 sys + 3.90 cusr 1.75 csys = 5.66 CPU) ok 28388 ms ( 0.00 usr 0.00 sys + 3.74 cusr 1.81 csys = 5.55 CPU) --compress=zstd (no parallelism) ok 28310 ms ( 0.00 usr 0.01 sys + 3.81 cusr 1.83 csys = 5.65 CPU) ok 28277 ms ( 0.01 usr 0.00 sys + 3.71 cusr 1.87 csys = 5.59 CPU) So apparently, zstd if available is a bit better than gzip and parallelism is better than no. But the differences are small -- half a second or so. The total increase in runtime in the best case is about four seconds. In all cases I used the same parallelism in pg_restore than pg_dump; not sure if that could cause a difference. -- Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
