We have a requirement to create a histogram on a specified column (release_flag) using FND_STATS.LOAD_HISTOGRAM_COLS(). This column has only two values ‘N’ and ‘Y’. We need to create the histogram on this column for the value of Flag status ‘N’.

Please share your views, syntax and advice to create the histogram.

This would be a great help to me.

Regards,

Srinivas vangari.

Hence a lot of parameters are hidden (parameter name starts with ‘_’ ) you cannot retrieve them using the V$PARAMETER View. With Oracle 10G about 80 Parameters (hidden + not hidden) are defined for example matching the pattern ‘%optim%’;

The – Script is a short variant of Pete Finnigan’s hidden parameter Script:
http://www.petefinnigan.com/check_parameter.sql

SELECT
  x.ksppinm name,
  y.ksppstvl VALUE,
  decode(ksppity,
    1,   'BOOLEAN',
    2,   'STRING',
    3,   'INTEGER',
    4,   'PARAMETER FILE',
    5,   'RESERVED',
    6,   'BIG INTEGER',
    'UNKNOWN') typ,
  decode(ksppstdf,
    'TRUE',   'DEFAULT VALUE',
    'FALSE',   'INIT.ORA') isdefault,
  decode(bitand(ksppiflg / 256,   1),
    1,   'IS_SESS_MOD(TRUE)',
    'FALSE') isses_modifiable,
  decode(bitand(ksppiflg / 65536,   3),
    1,   'MODSYS(NONDEFERED)',
    2,   'MODSYS(DEFERED)',
    3,   'MODSYS(*NONDEFERED*)',
    'FALSE') issys_modifiable,
  decode(bitand(ksppstvf,   7),
    1,   'MODIFIED_BY(SESSION)',
    4,   'MODIFIED_BY(SYSTEM)',
    'FALSE') is_modified,
  decode(bitand(ksppstvf,   2),
    2,   'ORA_STARTUP_MOD(TRUE)',
    'FALSE') is_adjusted,
  ksppdesc description,
  ksppstcmnt update_comment
FROM x$ksppi x,
  x$ksppcv y
WHERE x.inst_id = userenv('Instance')
 AND y.inst_id = userenv('Instance')
 AND x.indx = y.indx
 AND x.ksppinm LIKE '%optim%';

Talking about hidden parameters, I must include the following section:

!! DO NOT CHANGE HIDDEN PARAMETERS WITHOUT THE RECOMMENDATION OF ORACLE SUPPORT !!

HTH
Karl

PS.: Thanks Pete for this great hidden parameter script!

The actual dynamic performance views are identified by the prefix V_$. Public synonyms for these views have the prefix V$. You should access only the V$ objects, not the V_$ objects.

For almost every V$ view, Oracle has a corresponding GV$ (global V$) view. In addition to the V$ information, each GV$ view contains an extra column named INST_ID of datatype NUMBER. The INST_ID column displays the instance number from which the associated V$ view information was obtained.

Related documentation.

At customer sites very often I can see the transaction load via the amount of redo which was generated.

For best overview I like to query the amount of redo generated per hour:

SELECT Start_Date,
       Start_Time,
       Num_Logs,
       Round(Num_Logs * (Vl.Bytes / (1024 * 1024)),
             2) AS Mbytes,
       Vdb.NAME AS Dbname
  FROM (SELECT To_Char(Vlh.First_Time,
                       'YYYY-MM-DD') AS Start_Date,
               To_Char(Vlh.First_Time,
                       'HH24') || ':00' AS Start_Time,
               COUNT(Vlh.Thread#) Num_Logs
          FROM V$log_History Vlh
         GROUP BY To_Char(Vlh.First_Time,
                          'YYYY-MM-DD'),
                  To_Char(Vlh.First_Time,
                          'HH24') || ':00') Log_Hist,
       V$log Vl,
       V$database Vdb
 WHERE Vl.Group# = 1
 ORDER BY Log_Hist.Start_Date,
          Log_Hist.Start_Time;

Sample output:

START_DATE START_TIME NUM_LOGS               MBYTES                 DBNAME
---------- ---------- ---------------------- ---------------------- ---------
2006-01-24 11:00      1                      100                    MYDB
2006-01-24 14:00      2                      200                    MYDB
2006-01-24 16:00      1                      100                    MYDB
2006-01-24 18:00      1                      100                    MYDB
2006-01-24 20:00      5                      500                    MYDB
2006-01-24 21:00      14                     1400                   MYDB
2006-01-24 22:00      11                     1100                   MYDB
2006-01-25 00:00      1                      100                    MYDB
...

HTH

Karl

1 – ( physical reads / ( consistent gets + db block gets ) )

A better formula is:

1 – ( ( physical reads – (physical reads direct + physical reads direct (lob)) ) /
( db block gets + consistent gets – (physical reads direct + physical reads direct (lob)) )

In Oracle8.0 onwards it is possible to use multiple buffer pools. The hit ratios for each pool can be calculated using:

SELECT
    name,
    1-(physical_reads / (consistent_gets + db_block_gets ) )  "HIT_RATIO"
FROM V$BUFFER_POOL_STATISTICS
WHERE ( consistent_gets + db_block_gets ) !=0

except for 8.1.7 where due to a bug one must resort to the previous formula.

Vadim Bobrov
Oracle Database Tools
http://www.fourthelephant.com

declare
  res varchar2(1);
begin
  for i in 1..10000000 loop
    select dummy into res from dual;
  end loop;
end;

Don’t do it on production!! (test in development first)

Vadim Bobrov
Oracle Database Tools
http://www.fourthelephant.com

• Slow joins (Full Table Scans) between parent/child tables
• Deadlocks when updating or deleting a parent key.

The following script is by Thomas Kyte and was very helpfull in locating unindexed foreign keys:

http://asktom.oracle.com/~tkyte/unindex/unindex.sql

column columns format a20 word_wrapped
column table_name format a30 word_wrapped

select decode( b.table_name, NULL, '****', 'ok' ) Status,
    a.table_name, a.columns, b.columns
from
( select substr(a.table_name,1,30) table_name,
   substr(a.constraint_name,1,30) constraint_name,
      max(decode(position, 1,     substr(column_name,1,30),NULL)) ||
      max(decode(position, 2,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position, 3,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position, 4,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position, 5,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position, 6,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position, 7,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position, 8,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position, 9,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position,10,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position,11,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position,12,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position,13,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position,14,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position,15,', '||substr(column_name,1,30),NULL)) ||
      max(decode(position,16,', '||substr(column_name,1,30),NULL)) columns
    from user_cons_columns a, user_constraints b
   where a.constraint_name = b.constraint_name
     and b.constraint_type = 'R'
   group by substr(a.table_name,1,30), substr(a.constraint_name,1,30) ) a,
( select substr(table_name,1,30) table_name, substr(index_name,1,30) index_name,
      max(decode(column_position, 1,     substr(column_name,1,30),NULL)) ||
      max(decode(column_position, 2,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position, 3,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position, 4,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position, 5,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position, 6,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position, 7,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position, 8,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position, 9,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position,10,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position,11,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position,12,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position,13,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position,14,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position,15,', '||substr(column_name,1,30),NULL)) ||
      max(decode(column_position,16,', '||substr(column_name,1,30),NULL)) columns
    from user_ind_columns
   group by substr(table_name,1,30), substr(index_name,1,30) ) b
where a.table_name = b.table_name (+)
  and b.columns (+) like a.columns || '%'
/

Related Oracle documentation.

HTH Karl

SELECT Rownum AS Rank,
       Seg_Lio.*
  FROM (SELECT St.Owner,
               St.Obj#,
               St.Object_Type,
               St.Object_Name,
               St.VALUE,
               'LIO' AS Unit
          FROM V$segment_Statistics St
         WHERE St.Statistic_Name = 'logical reads'
         ORDER BY St.VALUE DESC) Seg_Lio
 WHERE Rownum <= 10
UNION ALL
SELECT Rownum AS Rank,
       Seq_Pio_r.*
  FROM (SELECT St.Owner,
               St.Obj#,
               St.Object_Type,
               St.Object_Name,
               St.VALUE,
               'PIO Reads' AS Unit
          FROM V$segment_Statistics St
         WHERE St.Statistic_Name = 'physical reads'
         ORDER BY St.VALUE DESC) Seq_Pio_r
 WHERE Rownum <= 10
UNION ALL
SELECT Rownum AS Rank,
       Seq_Pio_w.*
  FROM (SELECT St.Owner,
               St.Obj#,
               St.Object_Type,
               St.Object_Name,
               St.VALUE,
               'PIO Writes' AS Unit
          FROM V$segment_Statistics St
         WHERE St.Statistic_Name = 'physical writes'
         ORDER BY St.VALUE DESC) Seq_Pio_w
 WHERE Rownum <= 10;

HTH Karl

Works with >= 9.2

create index synopsis_idx on documents(synopsis)
  indextype is ctxsys.context
  parameters ('sync (every "FREQ=MINUTELY INTERVAL=5" memory 20M)');

The user creating the index must have the ‘ctxapp’ role and the ‘create job’ privilege. The values supplied for the ‘every’ parameter must be an Oracle Scheduler Calendaring Syntax expression or a PL/SQL expression that evaluates to a date or timestamp.

I had to bump up the number of buffer_gets because the above statement returned a LOT of rows.