Steve, > When we restore the postmaster process tries to use 100% of the CPU. > > The questions we have are: > > 1) What is postmaster doing that it needs so much CPU? Parsing mostly, and attribute conversion from text to DBMS native formats. > 2) How can we get our system to go faster? Use Postgres 8.1 or Bizgres. Get a faster CPU. These two points are based on our work to improve COPY speed, which led to a near doubling in Bizgres, and in the 8.1 version it's about 60-70% faster than in Postgres 8.0. There are currently two main bottlenecks in COPY, one is parsing + attribute conversion (if the postgres CPU is nailed at 100% that's what your limit is) and the other is the write speed through the WAL. You can roughly divide the write speed of your disk by 3 to get that limit, e.g. if your disk can write 8k blocks at 100MB/s, then your COPY speed might be limited to 33MB/s. You can tell which of these limits you've hit using "vmstat 1" on Linux or iostat on Solaris and watch the blocks input/output on your disk while you watch your CPU. > Note: We've tried adjusting the checkpoint_segements > parameter to no effect. No surprise. - Luke
