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Modification Log - GM Geoworkspace command processing performance gets slower / degrades over time

by Technical Evangelist on ‎09-26-2019 07:59 AM (94 Views)

Symptoms

Geoworkspace commands running slower than usual taking longer to process.

For example:

Opening/closing a geoworkspace

Updating the map window display.

Query processing

Editing geometry or feature records

Diagnosis

In a geoworkspace  when all insert, delete, and update command activities are executed, a record of that activity is stored in the “ModificationLog” table which is a GM metadata table. Overtime, this table grows larger(additional records) with each new activity which causes more processing time for the geoworkspace, thus the need to Clear the Modification Log(table).

 

An example of managing the modification log growth when running a command is in this article “Update Attributes performance improved by unchecking the "Enable undo and logging" option.

 

https://community.hexagongeospatial.com/t5/GeoMedia-Q-A/Update-Attributes-performance-improved-by-un...

Solution

Run GM Database Utilities and Clear Modification Log.

 

For Access, SQL Server(including SQL Azure), SQL Server Spatial(including SQL Azure),PostGIS, and GeoPackage databases.

 

Clear Modification Log - Clears all of the entries in the ModificationLog table and in the ModifiedTables table. ModifiedTables stores the names of the tables that have been modified, and ModificationLog stores all insert, delete, and update events that have taken place on these tables. Over time, these two tables (particularly the ModificationLog table) can become large enough to degrade performance. Thus, run this tool periodically in order to ensure optimal performance. This operation is not undoable.

 

For the Oracle Spatial Object Model

 

Clear Modification Log - Clears all of the entries in the GDOSYS.MODIFICATIONLOG table and in the GDOSYS.MODIFIEDTABLES table. GDOSYS.MODIFIEDTABLES stores the names of the tables that have been modified, and GDOSYS.MODIFICATIONLOG stores all insert, delete, and update events that have taken place on these tables. Over time, these two tables (particularly the MODIFICATIONLOG) can become large enough to degrade performance. Thus, run this tool periodically in order to ensure optimal performance. This operation is not undoable. For best results, you should handle this at the database level by scheduling a job to truncate the GDOSYS.MODIFICATIONLOG at regular intervals.

 

 

Best practice recommendation:

 

Set a scheduled time to run the "Clear Modification Log"  consistently to prevent the Modification Log table from growing too big impacting GeoMedia processing performance.

 

Depending on all insert, delete, and update command activities in a geoworkspce the Modification Log table should be cleared as often as every week to once a month etc..

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