Skip to main content

Sessions generating more redo or SQL queries generate heavy archive logs

Many times customer would ask us  that why more number of archive logs are being generated & flash recovery area (FRA) is getting filled with archive logs?  What are the queries or sessions involved in generating more archive logs?

below we can see the sql query to find which sessions and sql statements are generating more redo or more number of archive logs....

current sessions generating redo
=================================
set lines 2000
set pages 1000
col sid for 99999
col name for a09
col username for a14
col PROGRAM for a21
col MODULE for a25
select s.sid,sn.SERIAL#,n.name, round(value/1024/1024,2) redo_mb, sn.username,sn.status,substr (sn.program,1,21) "program", sn.type, sn.module,sn.sql_id
from v$sesstat s join v$statname n on n.statistic# = s.statistic#
join v$session sn on sn.sid = s.sid where n.name like 'redo size' and s.value!=0 order by
redo_mb desc;

From the above query we can have the session and sql id which generates redo currently in a descending order.

Output:
current sessions generating redo









The above method is for current situation.

Sometimes customer would ask the sql query which generated more archive logs sometimes before or days before (not for current archive logs generation which is explained in this post).  We'll see the steps for this scenario in the next post...

Comments

Post a Comment

Popular posts from this blog

Export and import multiple schema using expdp/impdp (Data Pump utility)

Use the below sql query to export and import multiple schema: expdp schemas=schema1,schema2,schema3 directory=DATA_PUMP_DIR dumpfile=schemas120514bkp.dmp exclude=statistics logfile=expdpschemas120514.log impdp schemas=schema1,schema2,schema3 directory=DATA_PUMP_DIR dumpfile=schemas120514bkp.dmp logfile=impdpschemas120514.log sql query to export and import a schema: expdp schemas=schema directory=DATA_PUMP_DIR dumpfile=schema120514bkp.dmp exclude=statistics logfile=expdpschema120514.log impdp schemas=schema directory=DATA_PUMP_DIR dumpfile=schema120514bkp.dmp logfile=expdpschema120514.log Parameter STATISTICS=NONE can either be used in export or import. No need to use the parameter in both. To export meta data only to get ddl of the schemas: expdp schemas=schema1,schema2,schema3 directory=TEST_DIR dumpfile=content.dat content=METADATA_ONLY exclude=statistics To get the DDL in a text file: impdp directory=TEST_DIR sqlfile=sql.dat logfile=sql.log dumpfil...
3 comments
Read more

Pinning execution plan for a sql_id using 'SQL Profile' to consistently reproduce a good plan

Deal all, Below post content is not my own. It is taken from MOSC document but the example shown below is taken from our environment. I got to know the below topic when we had experienced the bad SQL query performance in one of our production environment during daily batch running time. Hence we had implemented the same mentioned in the title "Pinning execution plan for a sql_id using 'SQL Profile' to consistently reproduce a good plan". Introduction The "cost-based optimizer (CBO or just optimizer) is the part of database software that determines the most efficient means of accessing the specified data (or at least what it "calculates" as the most efficient). The optimizer determines which execution plan is most efficient by considering several sources of information, including query conditions, available access paths, statistics gathered for the system, and hints. Some changes in those conditions may affect the calculations of the plan...
9 comments
Read more

Metrics Process Limit Usage percentage (%) is critical or warning in OEM or Cloud Control 12c or Cloud Control 13c

Please run the below queries to trace details during Metric alert "Process Limit % is >= 75" in OEM or Cloud Control 12c or Cloud Control 13c To check the Metrics Process Limit Usage (%): ***************************************************** set lines 300 col INITIAL_ALLOCATION for a17 col LIMIT_VALUE for a12 select resource_name,current_utilization,max_utilization, INITIAL_ALLOCATION,LIMIT_VALUE,((current_utilization*100)/(INITIAL_ALLOCATION)) as "Process limit %" from v$resource_limit where resource_name in ('processes'); The below query will give you all connected sessions (ACTIVE and INACTIVE) to instance: ******************************************************************************************************* set pages 100 set lines 1000 col SPID heading 'PID' for a06 col SID for 99999 col SERIAL# heading 'serial' for 999999 col SQL_ID for a14 col USERNAME for a10 col PROGRAM for a20 col MODULE for a18 col OSU...
Post a Comment
Read more