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Basically the same results as for Postgres 10 below. (I added a test without the new parallelism.)

Basically the same results as for Postgres 10 below. (I also added a test without the new parallelism to the fiddle, to compare apples with apples.)

Since Postgres 9.4 there's also the FILTER clause. Details:

Which is the true king of performance, even without index.
With an applicable index it can be faster by orders of magnitude, especially with index-only scans.

Postgres 10

Since Postgres 9.4 there's also the aggregate FILTER clause. See:

... which is the true king of performance, even without index.
With an applicable index it can be faster by orders of magnitude, especially with index-only scans.

Postgres 13

db<>fiddle here

Basically the same results as for Postgres 10 below. (I added a test without the new parallelism.)

Postgres 10

##Benchmarks

###Old test for Postgres 9.1 To verify I ran a quick test with EXPLAIN ANALYZE on a real life table in PostgreSQL 9.1.6.

Benchmarks

Old test for Postgres 9.1

To verify I ran a quick test with EXPLAIN ANALYZE on a real life table in PostgreSQL 9.1.6.