debasis maity

12+ years of rich experience on Database Administrations and on Infrastructure Solution Architect. AWS Certified Solution Architect and Senior Oracle DBA
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debasis maity 's Posts

Performance monitoring or tuning tool for SQL query taking long time using various tools   In that post,I will explain using various method or tool to investigate performance problem of particular sql query. Let me create a test case first   create table test_c(id number,name char(100),address char(100),create_date date); create table… Continue Reading Performance monitoring or tuning tool for SQL query taking long time using various tools like explain plan,sql monitor,awrsqrpt,sqlhc

1.General Information Memory versions of statistics regularly transferred to disk by MMON. AWR stores base statistics:-counters and value statistics. ASH data is firstly captured first to memory in 1 second interval for active sessions only.ASH data is reduced by 10 times sample in memory data.ASH data is used by ADDM.… Continue Reading AWR setup and configuration

We need to enable DDL logging sometimes to track all DDL operations performed in database level.   Step 1:-Please set ENABLE_DDL_LOGGING to TRUE   Enter user-name: / as sysdba SQL> show parameter ENABLE_DDL_LOGGING; NAME TYPE VALUE ———————————— ———– —————————— enable_ddl_logging boolean FALSE SQL> alter system set ENABLE_DDL_LOGGING=TRUE; System altered. Step… Continue Reading Enable DDL logging in Oracle 12c

You determine the level of statistics collection on the database by setting the value of the STATISTICS_LEVEL parameter. The values for this parameter are: • BASIC: No advisory or other statistical data is collected. You can manually set other statistic collection parameters such as TIMED_STATISTICS and DB_CACHE_ADVICE.Many of the statistics… Continue Reading STATISTICS_LEVEL parameter Oracle 12c

Real time performance tuning using Oracle SQL Developer   SQL developer is free tool can be downloaded from Oracle .I use it frequently as my performance tuning day to day arsenal.It is great tool to analyze both overall system performance as well as particular SQL tuning. Let me go thorugh… Continue Reading Real time performance tuning using Oracle SQL Developer

How to investigate real time over all performance bottleneck (enq: TX – row lock contention) using OS tools like top/sar/vmstat,ASH,AWR,ORATOP and OEM   I will simulate “row lock contention” using following procedure( I will resue my test case mentioned in Test case 4:-Now I will run update in parallel 10… Continue Reading How to investigate real time over all performance bottleneck (enq: TX – row lock contention) using OS tools like top/sar/vmstat,ASH,AWR,ORATOP and OEM

Test case preparation   I am going to create test case to simulate different index test cases   Test case 1:-First we create procedure to parallel insert in 10 sessions.The insert query will insert data based on random values generated from select query.Please note I will run gather stats after… Continue Reading Test case when index size can grow than table size and effect of rebuild index

AWR report analysis 12c in depth-part 2 This document is continuation of AWR report analysis in depth step by step which will provide you an idea to understand AWR report more quickly. Please refer to first part:- http://clouddba.co/awr-report-analysis-depth-part-1/ H.SQL Ordered by Elapsed Time in AWR REPORT For A:- For B:-… Continue Reading AWR report analysis 12c in depth-part 2

1.Let me  create a test case : I will take different OS statistics and run time statistics to compare with AWR report generated after execution. Case A.About test case in lower CPU:- I will create a table first create table t (id number, sometext varchar2(50),my_date date) tablespace data; Now I… Continue Reading AWR report analysis in 12c depth-part 1

First we need to load data SQL> alter session set tracefile_identifier=’ABC’; Session altered. Elapsed: 00:00:00.01 SQL> alter system set events ‘10046 trace name context forever, level 12′; System altered. Elapsed: 00:00:00.18 SQL> create table t1(c1 number,c2 char(2000)); Table created. Elapsed: 00:00:00.03 SQL> set autotrace on; SQL> set autotrace traceonly; SQL>… Continue Reading Comparison between exadata and non-exadata executions test case