Exadata and System Statistics

Question

Hi, there,
This might be a dumb question – but is it necessary to gather system statistics on Exadata machines?
I (fairly) recently migrated my Production EDW from a V2 quarter-rack to an X3-2 quarter-rack. On a “normal” system, if I migrated the database to a different (faster) server, I would look at regathering the system statistcs.
Is this something that’s sensible or worthwhile with Exadata?
Mark

Answer 1

Hi Mark,
Before you gather system stats you can run the following sql to get your current values.
SET SERVEROUTPUT ON
DECLARE
  STATUS VARCHAR2(20);
  DSTART DATE;
  DSTOP DATE;
  PVALUE NUMBER;
  PNAME VARCHAR2(30);
BEGIN
   PNAME := 'CPUSPEEDNW';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('cpuspeednw                  : '||pvalue);
   PNAME := 'IOSEEKTIM';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('ioseektime in ms            : '||pvalue);
   PNAME := 'IOTFRSPEED';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('iotfrspeef                  : '||pvalue);
   PNAME := 'SREADTIM';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('single block readtime in ms : '||pvalue);
   PNAME := 'MREADTIM';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('multi block readtime in ms  : '||pvalue);
   PNAME := 'CPUSPEED';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('cpuspeed                    : '||pvalue);
   PNAME := 'MBRC';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('multiblock read count       : '||pvalue);
   PNAME := 'MAXTHR';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('max threads                 : '||pvalue);
   PNAME := 'SLAVETHR';
   DBMS_STATS.GET_SYSTEM_STATS(status, dstart, dstop, pname, pvalue);
   DBMS_OUTPUT.PUT_LINE('slave threads               : '||pvalue);
  END;
Best advice I can give would be to check Doc ID 1274318.1 and search for dbms_stats.
Regards,
Tycho