Mark Wong wrote:
On Fri, Jan 07, 2005 at 10:13:52AM -0800, Josh Berkus wrote:
Mark,
All default parameters. Matthew also recommended using theInteresting ... the default parameters are quite conservative, running only when the table has doubled in new rows. So if those spikes are vacuums, then the DBT2 test is updating or adding 100% of the rows in the orders table every 6-8 minutes? Does that seem right?
vacuum_delay setting so I was about to try that.
Some hand-wavey math here:
We start with 18,000,000 rows in the orders table.
Based one 3281 transactions per minute for just the new-order transaction: 288 transactions per minute for delivery
New-order inserts 3281 rows per minute (not counting the 1% of rollbacks.) Delivery updates 288 rows per minute in orders.
So no, we're not change that many rows per minute...
Except the thing pg_autovacuum is actually doing is Analyzing the district table (4800 rows, takes ~15 sec) and vacuuming the warehouse table (66,000, takes ~50sec) which takes about 50 seconds. Since the default vacuum sleep time is 5 minutes, that would explain the dip every 6 minutes.
Matthew
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