SQL Server Index and Statistics Maintenance

https://ola.hallengren.com/sql-server-index-and-statistics-maintenance.html

Oracle waits прозрачно

https://sites.google.com/site/embtdbo/wait-event-documentation/oracle-io-waits

Linux 'screen' command

It is very useful to use screen in the terminal leaving your session at work with a process and return to it at home. Below is example with steps sequence of using the 'screen'. 

$ script -c 'screen' /dev/null

$ screen -ls

There are screens on:

        32156.pts-8.host022     (Attached)

        25681.xdbfix    (Attached)

        3074.pts-8.host022      (Attached)

        25658.pts-2.host022     (Attached)

        1289.pts-11.host022     (Detached)

5 Sockets in /var/run/screen/S-oracle.

$ screen -r 1289.pts-11.host022

Multiple AWR reports with one hour break up

It seems strange, but sometimes Application support asks about AWR Reports on 1-2 days with one hour break up.

In this case it is useful  multiple_awr.sql script from
https://oracle-base.com/dba/script?category=10g&file=generate_multiple_awr_reports.sql

First to identify snap range for the date you can use the following:

set linesize 500

set head off

--col snap_id for a45

col begin_interval_time for a30

select snap_id,begin_interval_time,end_interval_time from dba_hist_snapshot

where trunc(begin_interval_time) = to_date('03/05/2017','DD/MM/YYYY')

order by snap_id;

and then use the multiple_awr.sql script replacing values of the: 

  l_snap_start       NUMBER := 7724;
  l_snap_end         NUMBER := 7730;

------- multiple_awr.sql ----------------------------------------------------------------------------

-- File Name    : http://www.oracle-base.com/dba/10g/generate_multiple_awr_reports.sql
-- Author       : DR Timothy S Hall
-- Description  : Generates AWR reports for all snapsots between the specified start and end point.
-- Requirements : Access to the v$ views, UTL_FILE and DBMS_WORKLOAD_REPOSITORY packages.
-- Call Syntax  : Create the directory with the appropriate path.
--                Adjust the start and end snapshots as required.
--                @generate_multiple_awr_reports.sql
-- Last Modified: 02/08/2007
-- -----------------------------------------------------------------------------------
CREATE OR REPLACE DIRECTORY awr_reports_dir AS '/tmp/awr';

DECLARE
  -- Adjust before use.
  l_snap_start       NUMBER := 7724;
  l_snap_end         NUMBER := 7730;
  l_dir              VARCHAR2(50) := 'AWR_REPORTS_DIR';

  l_last_snap        NUMBER := NULL;
  l_dbid             v$database.dbid%TYPE;
  l_instance_number  v$instance.instance_number%TYPE;
  l_file             UTL_FILE.file_type;
  l_file_name        VARCHAR(50);

BEGIN
  SELECT dbid
  INTO   l_dbid
  FROM   v$database;

  SELECT instance_number
  INTO   l_instance_number
  FROM   v$instance;

  FOR cur_snap IN (SELECT snap_id
                   FROM   dba_hist_snapshot
                   WHERE  instance_number = l_instance_number
                   AND    snap_id BETWEEN l_snap_start AND l_snap_end
                   ORDER BY snap_id)
  LOOP
    IF l_last_snap IS NOT NULL THEN
      l_file := UTL_FILE.fopen(l_dir, 'awr_' || l_last_snap || '_' || cur_snap.snap_id || '.htm', 'w', 32767);

      FOR cur_rep IN (SELECT output
                      FROM   TABLE(DBMS_WORKLOAD_REPOSITORY.awr_report_html(l_dbid, l_instance_number, l_last_snap, cur_snap.snap_id)))
      LOOP
        UTL_FILE.put_line(l_file, cur_rep.output);
      END LOOP;
      UTL_FILE.fclose(l_file);
    END IF;
    l_last_snap := cur_snap.snap_id;
  END LOOP;

EXCEPTION
  WHEN OTHERS THEN
    IF UTL_FILE.is_open(l_file) THEN
      UTL_FILE.fclose(l_file);
    END IF;
    RAISE;
END;
/

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