>> The whole concept of "lag" with the rate limit is complicated. > > I must agree on that point, their interpretation is subtle. > >> At one point I thought this should be a debugging detail, rather than >> exposing the user to it. The problem is that if you do that, you might >> not notice that your limit failed to work as expected. Maybe it's >> good enough in a case like this that the user will see they tried to >> limit at 10000, but they only got 7135, so something must not have >> worked as expected. > > Yep. As I suggested in answering to Tatsuo, the process can catch up > later, so you could have 10000 in the end even with something amiss.
Fabian, I did another case. First, I run pgbench without -R. $ ./pgbench -p 5433 -S -n -c 10 -T 300 test ./pgbench -p 5433 -S -n -c 10 -T 300 test transaction type: SELECT only scaling factor: 1 query mode: simple number of clients: 10 number of threads: 1 duration: 300 s number of transactions actually processed: 2945652 tps = 9818.741060 (including connections establishing) tps = 9819.389689 (excluding connections establishing) So I thought I could squeeze 10000 TPS from my box. Then I tried with -R 5000 tps. $ ./pgbench -p 5433 -S -n -c 10 -T 300 -R 5000 test ./pgbench -p 5433 -S -n -c 10 -T 300 -R 5000 test transaction type: SELECT only scaling factor: 1 query mode: simple number of clients: 10 number of threads: 1 duration: 300 s number of transactions actually processed: 1510640 average rate limit lag: 0.304 ms (max 19.101 ms) tps = 5035.409397 (including connections establishing) tps = 5035.731093 (excluding connections establishing) As you can see, I got about 5000 tps as expected. But I'm confused by the lag: 0.304 ms * 1510640 = 459.2 seconds, which is longer than 300 seconds (specified by -T). Am I missing something? -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
