Finding large historic granules

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ClearSCADA is not designed to handle individual historic granules that are larger than about 1.3MB for Historic Data and 5MB for Alarm and Event Data (see the online help article "Operational Limitations - Server").
Exceeding this limitation may cause extended read locking when the historic granules are loaded, particularly on slower media such as magnetic disks.

Where possible, such granules should be identified and the cause of the abnormally high historic storage rate rectified. It may be advisable to remove the affected granules from the system to prevent performance degradation when searching. An alternative is to alter the stream size, although changing this may require downtime.

The largest granule for each stream can be seen at a glance in the Server Status tool or DBSnapshot in the Historic/Historian page, check the Largest File column.

This article covers a few approaches to identifying large historic granules.

SQL Query

These queries will list the granule sizes and approximate file locations ordered by size including an approximate "% Rated Maximum Size".
The queries select data from the historic index tables CDBHISTORICFILE and CDBEVENTFILE without having to load the granules themselves.

Find large historic granules in the Raw Historic stream.

SELECT TOP( 50 )    RECORDCOUNT AS "_RECORDCOUNT", FORMATVALUE( RECORDCOUNT / 40320.0 * 100.0 USING '0.00' ) || '%' AS PERCENTRATEDMAXSIZE, 'Hd' || 'I' || FORMATVALUE( ( OBJECTID / 256 ) USING '00000' ) || '\' || FORMATVALUE( OBJECTID USING '000000' ) || '\WK' || FORMATVALUE( GRANULE USING '0000000' ) || '.HRD' AS RELATIVEHISTORICPATH, OBJECTID AS OBJECTID, STARTTIME AS PERIODSTARTING, FORMATVALUE( ( ( RECORDCOUNT * 32 ) / 1024.0 ) USING '0' ) || ' KB' AS FILESIZE, CDBPOINT.FULLNAME, CDBPOINT.IDFROM    CDBHISTORICFILE LEFT JOIN CDBPOINT ON CDBHISTORICFILE.OBJECTID = CDBPOINT.IDORDER BY    "_RECORDCOUNT" DESC

Find large historic granules in the Event stream (assuming 256 objects per stream).

SELECT TOP( 50 )    RECORDCOUNT AS "_RECORDCOUNT", FORMATVALUE( RECORDCOUNT / 6825.0 * 100.0 USING '0.00' ) || '%' AS PERCENTRATEDMAXSIZE, 'Jn' || 'I' || FORMATVALUE( STREAM USING '00000' ) || '\H' || FORMATVALUE( GRANULE USING '0000000' ) || '.HRD' AS RELATIVEHISTORICPATH, CAST( ( STREAM * 256 ) AS STRING ) || ' - ' || CAST( ( ( STREAM + 1 ) * 256 - 1 ) AS STRING ) AS OBJECTIDRANGE, STARTTIME AS PERIODSTARTING, FORMATVALUE( ( ( RECORDCOUNT * 768 ) / 1024.0 ) USING '0' ) || ' KB' AS FILESIZEFROM    CDBEVENTFILEORDER BY    "_RECORDCOUNT" DESC

To analyse the distribution of event files per stream:

SELECT  MIN( STREAM ) AS "STREAM No.", COUNT( RECORDCOUNT ) AS "TotalFiles", SUM( RECORDCOUNT ) AS "TotalRecords", SUM( CASE  WHEN RECORDCOUNT > 7500 THEN 1 ELSE 0 END ) AS "7500 plus", SUM( CASE  WHEN RECORDCOUNT > 15000 THEN 1 ELSE 0 END ) AS "15000 plus", SUM( CASE  WHEN RECORDCOUNT > 30000 THEN 1 ELSE 0 END ) AS "30000 plus", SUM( CASE  WHEN RECORDCOUNT > 60000 THEN 1 ELSE 0 END ) AS "60000 plus"FROM CDBEVENTFILEGROUP BY STREAMORDER BY "STREAM No." ASC

To analyse the distribution of event files over time (day base):

SELECT  MIN( FORMATVALUE( STARTTIME USING 'YYYY-MM-dd' ) ) AS "Date", COUNT( RECORDCOUNT ) AS "TotalFiles", SUM( RECORDCOUNT ) AS "TotalRecords", SUM( CASE  WHEN RECORDCOUNT > 7500 THEN 1 ELSE 0 END ) AS ">7500", SUM( CASE  WHEN RECORDCOUNT > 15000 THEN 1 ELSE 0 END ) AS ">15000", SUM( CASE  WHEN RECORDCOUNT > 30000 THEN 1 ELSE 0 END ) AS ">30000", SUM( CASE  WHEN RECORDCOUNT > 60000 THEN 1 ELSE 0 END ) AS ">60000"FROM CDBEVENTFILEGROUP BY FORMATVALUE( STARTTIME USING 'YYYY-MM-dd' )ORDER BY "Date" ASC

Batch Program

The following batch program can be used to find large historic granules.
It will search through a specified directory and all subdirectories for files that are larger than a specific size.

:bof@echo off & setlocal enableextensionsREMREM Recursively finds all files larger than a specified number of bytes within a specified path.REMREM Usage:REM   findlarge.bat "" REMREM Example 1:REM   findlarge.bat "c:\Database\Historic" 2097152REM Example 2:REM   findlarge.bat "c:\Database\Historic" 2097152 > output.txtREMREM:init  for /f "tokens=*" %%f in ('dir "%~1" /b /s /o-d') do (    if %%~zf GEQ %~2 echo %%~zf - %%~ff    )  endlocal & goto :end:end

This is an example of the batch file being run.

C:\utilities\findlarge>findlarge.bat "c:\Users\All Users\Control Microsystems\ClearSCADA\Database\History" 20971525047040 - c:\Users\All Users\ControlMicrosystems\ClearSCADA\Database\History\Historic\HdI000017325184- c:\Users\All Users\ControlMicrosystems\ClearSCADA\Database\History\Historic\HdI00000

"DIR /s"

"DIR /s" can be used to achieve similar results. Use the "DIR /s" command from the root of the historic folders and pipe the output to files. You end up with something like

Directory of C:\ProgramData\Schneider Electric\ClearSCADA\Database\History\Historic\HdI00000\00004003/05/2015  01:44 PM              .03/05/2015  01:44 PM              ..10/08/2014  10:27 AM               160 WK021589.HRD03/05/2015  01:43 PM                32 WK021610.HRD               2 File(s)            192 bytesDirectory of C:\ProgramData\Schneider Electric\ClearSCADA\Database\History\Historic\HdI00000\00004910/08/2014  10:18 AM              .10/08/2014  10:18 AM              ..10/08/2014  10:17 AM                96 WK021589.HRD               1 File(s)             96 bytes

This could be searched to identify large files.

"FORFILES"

"Forfiles" can be used to get a listing from files modified before / after a certain date. Use the "Forfiles" command from the root of the historic folders and pipe the output to files. 

C:\>  forfiles /P "ProgramData\Schneider Electric\ClearSCADA\Database\Journal" /S /D +01/03/2015 /C "cmd /c echo @path,@fsize" > JournalFilesSince0103215.csv

This could be used in case you can't use a SQL query.

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