Tom Lane <tgl@sss.pgh.pa.us> ezt írta (időpont: 2020. júl. 20., H, 15:38):
There are -j threads in the pgbench process, and -c connections to the server (hence -c backend processes on the server side). Each of the pgbench threads is responsible for sending queries to a subset of the connections. Setting -j more than -c is useless (I forget if it's actually an error). If you set -j to, say, half of -c then each thread has exactly two connections to manage. If -j is too small compared to -c then pgbench itself tends to become the bottleneck.
Without -j, we have N connections, but one thread. So this thread serves all of the connections one by one? The 1. and 2. and 3. connection while others do nothing (standing by)? Or like Round Robin: a job from C1, next job from C2, .... job from CN - then job from C1.... and no more jobs?
And if J = C means realtime parallel test? Because each thread has only one connection, and they work concurrently as real users do?
Then if I want to simulate 500 users heavy work, I need to set J=C=500?
