How to know whether I use analyze or DBMS_STATS

Automatic statistics gathering should be sufficient for most of the cases. And automatic statistics gathering is done by default during an overnight batch window.
In most cases automatic statistics gather is sufficient but still you may need to gather manually statistics if you do huge insert or update or delete on the table. You might know we can gather statistics by two ways.

1)Analyze command.
2)DBMS_STATS package.

By querying from the dba_tables view you can say by which method you gathered statistics. Let's see it with an example.
I am creating two tables named with_analyze and with_dbms_stats. On table with_analyze use analyze to estimate statistics and on table with_dbms_stats use DBMS_STATS package to gather statistics.

SQL> Create table with_analyze(col1 number);

Table created.

SQL> Create table with_dbms_stats(col1 number);

Table created.

SQL> analyze table with_analyze compute statistics;

Table analyzed.

SQL> exec dbms_stats.gather_table_stats('SYS','WITH_DBMS_STATS');

PL/SQL procedure successfully completed.

Now let's have a look at GLOBAL_STATS column of user_tables(contain only currently user owned table) or dba_tables(contain all table) table or all_tables(contain all tables to which current user has permission).

If you gather statistics on a table with analyze command then GLOBAL_STATS field will be FALSE for that table.

If you gather statistics on a table with DBMS_STATS package then GLOBAL_STATS field will be TRUE for that table.

SQL> select table_name,last_analyzed, GLOBAL_STATS from dba_tables where
table_name in ('WITH_ANALYZE','WITH_DBMS_STATS');

TABLE_NAME                     LAST_ANAL GLO
------------------------------ --------- ---
WITH_ANALYZE                   10-OCT-08 NO
WITH_DBMS_STATS                10-OCT-08 YES

Comments

Post a Comment

Popular posts from this blog

ORA-04062: timestamp of procedure has been changed

Problem Description In the database I have created one procedure named a as below. create or replace procedure a(a number) as begin insert into t1 values(1); commit; end; / Now after creating database link using remote database machine whenever I access this procedure "A" it executes successfully and I get value "1" in table t1. Like below in example where orastdby_m is the database link, shaik is the schema name and value 1 is the argument value though argument value is not used in the procedure. SQL> exec shaik.a@orastdby_m(1); PL/SQL procedure successfully completed. Now in the source database machine I changed the procedure as below. Though you can change anything like any literal; adding space or remove space. I changed value to be inserted from 1 to 2. create or replace procedure a(a number) as begin insert into t1 values(2); commit; end; / Now in the other database whenever I execute the procedure using database link it throws error ORA-04062. But subseq...
Read more

ORA-00939: too many arguments -when case arguments exceed 255

Problem Description In all Oracle 10.1g and oracle 10.2.0.1, 10.2.0.2, 10.2.0.3 whenever there is more than 255 arguments inside CASE statements then following error is returned. ORA-00939: too many arguments for function But surprisingly on Oracle 9.2 database the same code does not return any error. Cause of the Problem As we see the same code return error in 10g but it is well on 9.2. In fact this is problem of oracle 9.2 that it does not return any error. It should return error if there is more than 255 arguments inside CASE statements. In oracle 9.2 this is bug number 2909927 and this bug is fixed in oracle 10.1 and 10.2. That's why in 10.2 and 10.1 error returns if arguments exceed 255. Up to Oracle 10.2.0.3 and earlier version, the arguments of CASE statement is limit to 255 and it does not support exceed over 255 and hence error return if it exceed. However in Oracle 10.2.0.4 and later the arguments limit of CASE statement has increased to 32767. Solution of the Problem Opt...
Read more

ORA-31655: no data or metadata objects selected for job

Problem Description You are going to do data pump export operation in order to export objects based on filtering via EXCLUDE or INCLUDE parameter of expdp. In this example you wanted tables 'ACCOUNT_GROUP','ADDRESS','AREA_GROUP' and all the tables starting with word CV(like 'CV', 'CV_EXPERIENCE', 'CV_EDUCATION' etc) Your parameter file is like below. userid=smilebd/a directory=d dumpfile=b.dmp include =TABLE:"IN('ACCOUNT_GROUP','ADDRESS','AREA_GROUP')" include =TABLE:"LIKE 'CV%' " And you invoke expdp as expdp parfile=d:\parfile.txt from command line. But it fails with below message on my windows PC. C:\>expdp parfile=d:\parfile.txt Export: Release 10.1.0.4.2 - Production on Thursday, 29 January, 2009 14:53 Copyright (c) 2003, Oracle. All rights reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Produc tion With the Partitioning, OLAP and Data Mining ...
Read more