Oracle Tables - Indexes

Tabs w/ Questionable Inds

TABLES WITH QUESTIONABLE INDEX(ES) NOTES:

  Owner - Owner of the table

  Table Name - Name of the table

  Column - Name of the column in question

  The above query shows all tables that have more than one index with the same leading column. These indexes can cause queries to use an inappropriate indexes; in other words, Oracle will use the index that was created most recently if two indexes are of equal ranking. This can cause different indexes to be used from one environment to the next (e.g., from DEV to TEST to PROD).

  The information does not automatically indicate that an index is incorrect; however, you may need to justify the existence of each of the indexes above.

select   

TABLE_OWNER,

   TABLE_NAME,

   COLUMN_NAME

from  dba_ind_columns

where COLUMN_POSITION=1

and  TABLE_OWNER not in ('SYS','SYSTEM')

group by TABLE_OWNER, TABLE_NAME, COLUMN_NAME

having  count(*) > 1

              

Tabs With More Than 5 Inds

TABLES WITH MORE THAN 5 INDEXES NOTES:

  Owner - Owner of the table

  Table Name - Name of the table

  Index Count - Number of indexes

select    OWNER,

   TABLE_NAME,

   COUNT(*) index_count

from  dba_indexes

where     OWNER not in ('SYS','SYSTEM')

group     by OWNER, TABLE_NAME

having  COUNT(*) > 5

order by COUNT(*) desc, OWNER, TABLE_NAME

Tables With No Indexes

TABLES WITHOUT INDEXES NOTES:

  Owner - Owner of the table

  Table Name - Name of the table

select    OWNER,

   TABLE_NAME

from

(

select    OWNER,

   TABLE_NAME

from dba_tables

minus

select    TABLE_OWNER,

   TABLE_NAME

from dba_indexes

)

orasnap_noindex

where OWNER not in ('SYS','SYSTEM')

order by OWNER,TABLE_NAME

Tables With No PK

NO PRIMARY KEY NOTES:

  Table Owner - Owner of the table

  Table Name - Name of the table

select  OWNER,

   TABLE_NAME

from    dba_tables dt

where   not exists (

        select  'TRUE'

        from    dba_constraints dc

        where   dc.TABLE_NAME = dt.TABLE_NAME

        and     dc.CONSTRAINT_TYPE='P')

and   OWNER not in ('SYS','SYSTEM')

order by OWNER, TABLE_NAME

Disabled Constraints

DISABLED CONSTRAINT NOTES:

  Owner - Owner of the table

  Table Name - Name of the table

  Constraint Name - Name of the constraint

  Constraint Type - Type of constraint

  Status - Current status of the constraint

select  OWNER,

        TABLE_NAME,

        CONSTRAINT_NAME,

        decode(CONSTRAINT_TYPE, 'C','Check',

                                'P','Primary Key',

                                'U','Unique',

                                'R','Foreign Key',

                                'V','With Check Option') type,

        STATUS

from dba_constraints

where STATUS = 'DISABLED'

order by OWNER, TABLE_NAME, CONSTRAINT_NAME

FK Constraints

FOREIGN KEY CONSTRAINTS NOTES:

  Table Owner - Owner of the table

  Table Name - Name of the table

  Constraint Name - Name of the constraint

  Column Name - Name of the column

  Referenced Table - Name of the referenced table

  Reference Column - Name of the referenced column

  Position - Position of the column

select    c.OWNER,

   c.TABLE_NAME,

   c.CONSTRAINT_NAME,

   cc.COLUMN_NAME,

   r.TABLE_NAME,

   rc.COLUMN_NAME,

   cc.POSITION

from dba_constraints c,

   dba_constraints r,

   dba_cons_columns cc,

   dba_cons_columns rc

where c.CONSTRAINT_TYPE = 'R'

and   c.OWNER not in ('SYS','SYSTEM')

and   c.R_OWNER = r.OWNER

and   c.R_CONSTRAINT_NAME = r.CONSTRAINT_NAME

and   c.CONSTRAINT_NAME = cc.CONSTRAINT_NAME

and   c.OWNER = cc.OWNER

and   r.CONSTRAINT_NAME = rc.CONSTRAINT_NAME

and   r.OWNER = rc.OWNER

and   cc.POSITION = rc.POSITION

order by c.OWNER, c.TABLE_NAME, c.CONSTRAINT_NAME, cc.POSITION

FK Index Problems

FK CONSTRAINTS WITHOUT INDEX ON CHILD TABLE NOTES:

  Owner - Owner of the table

  Constraint Name - Name of the constraint

  Column Name - Name of the column

  Position - Position of the index

  Problem - Nature of the problem

  It is highly recommended that an index be created if the Foreign Key column is used in joining, or often used in a WHERE clause. Otherwise a table level lock will be placed on the parent table.

select    acc.OWNER,

   acc.CONSTRAINT_NAME,

   acc.COLUMN_NAME,

   acc.POSITION,

   'No Index' Problem

from      dba_cons_columns acc,

   dba_constraints ac

where     ac.CONSTRAINT_NAME = acc.CONSTRAINT_NAME

and   ac.CONSTRAINT_TYPE = 'R'

and     acc.OWNER not in ('SYS','SYSTEM')

and     not exists (

        select  'TRUE'

        from    dba_ind_columns b

        where   b.TABLE_OWNER = acc.OWNER

        and     b.TABLE_NAME = acc.TABLE_NAME

        and     b.COLUMN_NAME = acc.COLUMN_NAME

        and     b.COLUMN_POSITION = acc.POSITION)

order   by acc.OWNER, acc.CONSTRAINT_NAME, acc.COLUMN_NAME, acc.POSITION

Inconsistent Column Names

INCONSISTENT COLUMN DATATYPE NOTES:

  Owner - Owner of the table

  Column - Name of the column

  Table Name - Name of the table

  Datatype - Datatype of the column

select    OWNER,

   COLUMN_NAME,

   TABLE_NAME,

   decode(DATA_TYPE, 'NUMBER', DATA_PRECISION, DATA_LENGTH) datatype

from dba_tab_columns

where     (COLUMN_NAME, OWNER) in

      (select   COLUMN_NAME,

          OWNER

       from dba_tab_columns

       group by COLUMN_NAME, OWNER

      having   min(decode(DATA_TYPE, 'NUMBER', DATA_PRECISION, DATA_LENGTH)) <

         max(decode(DATA_TYPE, 'NUMBER', DATA_PRECISION, DATA_LENGTH)) )

and   OWNER not in ('SYS', 'SYSTEM')

order by COLUMN_NAME,DATA_TYPE

Object Extent Warning

TABLES THAT CANNOT EXTEND NOTES:

  Owner - Owner of the object

  Object Name - Name of the object

  Object Type - Type of object

  Tablespace - Name of the tablespace

  Next Extent - Size of next extent (bytes)

select    OWNER,

   SEGMENT_NAME,

   SEGMENT_TYPE,

   TABLESPACE_NAME,

   NEXT_EXTENT

from (

   select    seg.OWNER,

      seg.SEGMENT_NAME,

          seg.SEGMENT_TYPE,

      seg.TABLESPACE_NAME,

          t.NEXT_EXTENT

   from dba_segments seg,

          dba_tables t

   where (seg.SEGMENT_TYPE = 'TABLE'

   and   seg.SEGMENT_NAME = t.TABLE_NAME

   and   seg.owner = t.OWNER

   and    NOT EXISTS (

          select    TABLESPACE_NAME

             from dba_free_space free

             where free.TABLESPACE_NAME = t.TABLESPACE_NAME

             and   BYTES >= t.NEXT_EXTENT))

   union

   select    seg.OWNER,

      seg.SEGMENT_NAME,

          seg.SEGMENT_TYPE,

      seg.TABLESPACE_NAME,

          c.NEXT_EXTENT

   from dba_segments seg,

          dba_clusters c

   where     (seg.SEGMENT_TYPE = 'CLUSTER'

   and        seg.SEGMENT_NAME = c.CLUSTER_NAME

   and        seg.OWNER = c.OWNER

   and       NOT EXISTS (

          select    TABLESPACE_NAME

          from dba_free_space free

          where free.TABLESPACE_NAME = c.TABLESPACE_NAME

          and   BYTES >= c.NEXT_EXTENT))

   union

   select    seg.OWNER,

      seg.SEGMENT_NAME,

          seg.SEGMENT_TYPE,

      seg.TABLESPACE_NAME,

          i.NEXT_EXTENT

   from dba_segments seg,

          dba_indexes  i

   where     (seg.SEGMENT_TYPE = 'INDEX'

   and        seg.SEGMENT_NAME = i.INDEX_NAME

   and        seg.OWNER        = i.OWNER

   and        NOT EXISTS (

          select    TABLESPACE_NAME

                from dba_free_space free

                where free.TABLESPACE_NAME = i.TABLESPACE_NAME

          and   BYTES >= i.NEXT_EXTENT))

   union

   select    seg.OWNER,

      seg.SEGMENT_NAME,

          seg.SEGMENT_TYPE,

      seg.TABLESPACE_NAME,

          r.NEXT_EXTENT

   from dba_segments seg,

          dba_rollback_segs r

   where     (seg.SEGMENT_TYPE = 'ROLLBACK'

   and        seg.SEGMENT_NAME = r.SEGMENT_NAME

   and        seg.OWNER        = r.OWNER

   and        NOT EXISTS (

          select TABLESPACE_NAME

                from dba_free_space free

                where free.TABLESPACE_NAME = r.TABLESPACE_NAME

                and   BYTES >= r.NEXT_EXTENT))

)

orasnap_objext_warn

order by OWNER,SEGMENT_NAME

Segment Fragmentation

OBJECTS WITH MORE THAN 50% OF MAXEXTENTS NOTES:

  Owner - Owner of the object

  Tablespace Name - Name of the tablespace

  Segment Name - Name of the segment

  Segment Type - Type of segment

  Size - Size of the object (bytes)

  Extents - Current number of extents

  Max Extents - Maximum extents for the segment

  Percentage - Percentage of extents in use

  As of v7.3.4, you can set MAXEXTENTS=UNLIMITED to avoid ORA-01631: max # extents (%s) reached in table $s.%s.

  To calculate the MAXEXTENTS value on versions < 7.3.4 use the following equation: DBBLOCKSIZE / 16 - 7

  Here are the MAXEXTENTS for common blocksizes: 1K=57, 2K=121, 4K=249, 8K=505, and 16K=1017

  Multiple extents in and of themselves aren't bad. However, if you also have chained rows, this can hurt performance.

select    OWNER,

   TABLESPACE_NAME,

   SEGMENT_NAME,

   SEGMENT_TYPE,

   BYTES,

   EXTENTS,

   MAX_EXTENTS,

   (EXTENTS/MAX_EXTENTS)*100 percentage

from dba_segments

where SEGMENT_TYPE in ('TABLE','INDEX')

and   EXTENTS > MAX_EXTENTS/2

order by (EXTENTS/MAX_EXTENTS) desc

Extents reaching maximum

TABLES AND EXTENTS WITHIN 3 EXTENTS OF MAXIMUM :

  Owner - Owner of the segment

  Segment Name - Name of the segment

select owner "Owner",

       segment_name "Segment Name",

       segment_type "Type",

       tablespace_name "Tablespace",

       extents "Ext",

       max_extents "Max"

from dba_segments

where ((max_extents - extents) <= 3)

and owner not in ('SYS','SYSTEM')

order by owner, segment_name

Analyzed Tables

ANALYZED TABLE NOTES:

  Owner - Owner of the table

  Analyzed - Number of analyzed tables

  Not Analyzed - Number of tables that have not be analyzed

  Total - Total number of tables owned by user

  The ANALYZE statement allows you to validate and compute statistics for an index, table, or cluster. These statistics are used by the cost-based optimizer when it calculates the most efficient plan for retrieval. In addition to its role in statement optimization, ANALYZE also helps in validating object structures and in managing space in your system. You can choose the following operations: COMPUTER, ESTIMATE, and DELETE. Early version of Oracle7 produced unpredicatable results when the ESTIMATE operation was used. It is best to compute your statistics.

  A COMPUTE will cause a table-level lock to be placed on the table during the operation.

select OWNER,

   sum(decode(nvl(NUM_ROWS,9999), 9999,0,1)) analyzed,

   sum(decode(nvl(NUM_ROWS,9999), 9999,1,0)) not_analyzed,

   count(TABLE_NAME) total

from dba_tables

where OWNER not in ('SYS', 'SYSTEM')

group by OWNER

Recently Analyzed Tables

LAST ANALYZED TABLE NOTES:

  Owner - Owner of the table

  Table Name - Name of the table

  Last Analyzed - Last analyzed date/time

select    OWNER,

   TABLE_NAME,

   to_char(LAST_ANALYZED,'MM/DD/YYYY HH24:MI:SS') last_analyzed

from dba_tab_columns

where OWNER not in ('SYS','SYSTEM')

and   LAST_ANALYZED is not null

and COLUMN_ID=1

and   (SYSDATE-LAST_ANALYZED) < 30

order by (SYSDATE-LAST_ANALYZED)

Cached Tables

CACHED TABLE NOTES:

  Owner - Owner of the table

  Table Name - Name of the table

  Cache - Cached?

  Oracle 7.1+ provides a mechanism for caching table in the buffer cache. Caching tables will speed up data access and improve performance by finding the data in memory and avoiding disk reads.

select    OWNER,

   TABLE_NAME,

   CACHE

from dba_tables

where OWNER not in ('SYS','SYSTEM')

and CACHE like '%Y'

order by OWNER,TABLE_NAME