Raymond Raymond wrote:
Dear Oystein,
 In one of you former mails, you said:

From: [EMAIL PROTECTED] (Øystein Grøvlen)

   During checkpoint when I/O is slow this creates long queques of
   readers.  In my run with 20 clients, I observed read requests that
   took more than 20 seconds ......


I am coding on autimatic checkpoint and incremental checkpoint as
what we discussed before, I finished party of them and trying to
do some test on it. I am really interested in how you observed :

   I have observed single write
   operations that took almost 12 seconds ......

and

   readers.  In my run with 20 clients, I observed read requests that
   took more than 20 seconds ......


I ran a variant of the TPC-B benchmark with a large database (20 GB) and a large page cache (1 GB). I do not think you need TPC-B transactions to see this, but I think you need update-intensive transactions that frequently needs to load pages from disk. For example, single record updates where an index is used to locate the record. You will also need several connections in parallel (e.g., 20).

--
Øystein

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