Monthly Archives: March 2009

The v$osstat view shows certain OS-level metics such as number of CPUs, current system load, accumulated IO time, etc. Starting in 10gR2, it also records PHYSICAL_MEMORY_BYTES, which is the total size of physical memory on the server. See the documentation. … Continue reading →

I had a little excitement with the cursor: pin S wait on X wait event when a client’s website came grinding to a halt. The first thing I checked was blocking sessions… col username form a12 col event form a25 … Continue reading →

Sometimes I find the need to test disk IO rates, especially in the context of one of those delightful intra-office debates where the DBAs are blaming the lousy hardware for bad database performance and the sysadmins are blaming the lousy … Continue reading →

In Oracle, the standard way to calculate the difference (delta) between two values is using the LAG() analytic function. For example… Suppose you’ve got a table of numeric values– create table t as select rownum id, value from v$sesstat where … Continue reading →