[receiver/oracledb] Add additional metrics to compute Buffer Cache Hit Ratio

[atoulme]

Component(s)

receiver/oracledb

Is your feature request related to a problem? Please describe.

See https://www.learn-it-with-examples.com/database/oracle/database-tuning/buffer-cache-hit-ratio-oracle-database.html

With this query, users can compute the buffer cache hit ratio:

SELECT round((P1.value + P2.value - P3.value) / 
       (P1.value + P2.value)*100,2) "Cache Hit Ratio (DB)"
         FROM   v$sysstat P1, v$sysstat P2, v$sysstat P3
         WHERE  P1.name = 'db block gets'
         AND    P2.name = 'consistent gets'
         AND    P3.name = 'physical reads';

Describe the solution you'd like

Add 3 additional metrics:

• 'db block gets'
• 'consistent gets'
• 'physical reads'

Users can derive the ratio from those metrics.

Describe alternatives you've considered

No response

Additional context

No response