Heikki Linnakangas wrote:
Alvaro Herrera wrote:
Was this revisited?

Arranging the tests has taken me longer than I thought, but I now finally have the hardware and DBT-2 set up. I just finished a pair of 2h tests with autovacuum off, and continuous vacuum of the stock table. I'm trying to get the results uploaded on some public website so we can all see and discuss them.

I finally got around looking at this again.

I ran two 24h test runs with DBT-2, one with the patch and one without. To get comparable, predictable results, I turned autovacuum off and run a manual vacuum in a loop on the stock-table alone.

As expected, the steady-state of the stock table is smaller with the patch. But only by ~2%, that's slightly less than I expected.

But what surprises me is that response times went up a with the patch. I don't know why.

The full test results are here:


92 was run with the patch, 93 without it.

BTW: The iostat chart clearly shows the vacuum WAL flush problem. The WAL utilization jumps from ~20% to ~40% during the 2nd vacuum pass.

  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com

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