-

 


Findings – Step 1 (Cursor Cache: Recent Executions)



  1. Plan stability
    • Both p011aor and p012aor used the same plan hash (517933086).
    • Confirms this is not a plan regression issue.

  3. Execution volume
    • p011aor: ~6.2K executions.
    • p012aor: ~13.9K executions (2× higher).
    • Suggests heavier workload routed here (possibly service routing) or repeated runs.

  5. Elapsed time profile
    • p011aor: elapsed ~6,210s, dominated by CPU time (65%), very low IO waits.
    • p012aor: elapsed ~13,860s, dominated by IO waits (94%), very little CPU work.
    • Clear shift: p012aor performance is IO-bound, not CPU-bound.

  7. Rows processed
    • p011aor: ~18.7M rows.
    • p012aor: ~32.6M rows (~75% more).
    • Indicates either different bind values or different data distribution leading to more row access.

  9. Logical & physical IO
    • Buffer gets: 293M vs 421M (+43%).
    • Disk reads: 5.6M vs 11.9M (2× higher).
    • Reinforces that p012aor is performing heavier IO work.






✅ Step 1 Conclusion



  • Not a plan issue (same hash).
  • p012aor slowness is tied to IO: more rows processed, more disk reads, longer elapsed dominated by IO waits.
  • Likely next culprits:
    • Bind values (Step 2).
    • Object/data skew (Step 9).
    • Storage/TEMP IO latency (Steps 10–11).


Popular posts from this blog

-
Image
How to shutdown a Single Instance Database in Oracle 19c Overview Shutdown is an operation performed when a command is issued by the Administrator to bring down the Database or when it receives a signal to bring down the Database incase of a failure/malfunction or due to SHUTDOWN ABORT comm and execution. The options used by t he Administrator to bring down the Database is called as Shutdown Modes and the Database Server follows a sequence to shutdown a Database . Let's check how does that happen. Concepts The following are the shutdown Modes. Shutdown Modes A database administrator with SYSDBA or SYSOPER privileges can shut down the database using the SQL*Plus SHUTDOWN command or Enterprise Manager. The SHUTDOWN command has the following options that determine the shutdown behavior. Now let's look into each SHUTDOWN option in detail. SHUTDOWN ABORT  This mode is used for emergency situations, such as when shutdown with "IMMEDIATE" option doesn't work. This mode o...
Read more
-
How to startup a Single Instance Database in Oracle 19c Overview An Oracle Database goes through various stages until it is made available to the users. They are categorized into the below stages. Concepts The following are the stages of the startup sequence. Nomount   The instance is started, but is not yet associated with a database. The stages are as follows:  1. Searches for a server parameter file in a platform-specific default location and, if not found, for a text initialization parameter file (specifying STARTUP with the SPFILE or PFILE parameters overrides the default behavior)  2. Reads the parameter file to determine the values of initialization parameters  3. Allocates the SGA based on the initialization parameter settings  4. Starts the Oracle background processes  5. Opens the alert log and trace files and writes all explicit parameter settings to the alert log in valid parameter syntax At this stage, no database is associated with the instanc...
Read more
-
 PROMPT [STEP 11] I/O Latency during periods this SQL appeared COLUMN filetype_id   FORMAT 999 HEADING 'TYPE_ID' COLUMN ms_per_read   FORMAT 999.999 COLUMN ms_per_write  FORMAT 999.999 WITH r AS (   SELECT MIN(snap_id) b, MAX(snap_id) e   FROM   dba_hist_sqlstat   WHERE  sql_id='&sql_id' ) SELECT f.filetype_id,        ROUND(f.readtim  / DECODE(NULLIF(f.phyrds ,0),0,1,f.phyrds ),3) AS ms_per_read,        ROUND(f.writetim / DECODE(NULLIF(f.phywrts,0),0,1,f.phywrts),3) AS ms_per_write FROM   dba_hist_filestatxs f, r WHERE  f.snap_id BETWEEN r.b AND r.e GROUP  BY f.filetype_id, f.readtim, f.phyrds, f.writetim, f.phywrts ORDER  BY ms_per_read DESC NULLS LAST;
Read more