Are you receiving the following error: “Lock request conflicts with an established lock.” or unable to change any properties of your data via ArcCatalog?
This is a common occurrence that occurs when you are making schema changes such as:
a) Renaming a Feature class / table
b) Deleting a Feature class / table
c) Adding a new Feature class to a Feature dataset
d) Register as Versioned…
e) Deleting / Adding a Field
f) Applying geodatabase behaviour (Eg. Domains, Subtypes, Relationship classes)
When making any of the above changes, you are making a change to the structure of the dataset, in essence, a change to the schema of the database object. The most common cause of a schema lock is displaying or viewing a dataset in ArcMap. A schema lock error or issue occurs when schema changes to a database object (Feature class / Table / Feature Dataset) is attempted to be made via ArcCatalog, *while* another user or application (ArcMap) is accessing the data at the same time.
In ArcSDE geodatabases, more than one user can be viewing and editing the same data at the same time. To be able to work with data in a geodatabase for applications such as ArcMap, the application must work on the principle that the geodatabase schema remains fixed and is not changing at any time that you are working with the geodatabase contents. For example, while adding a feature class from a geodatabase to your map, its schema cannot be altered by you or another user. Once you have removed the feature class from your map and no other users are querying or editing that feature class, its schema can be altered.
Thus, in order to make a schema change (such as adding a new field to a feature class, or even adding a new feature class to a feature dataset), the feature class cannot be accessed by another ArcGIS application such as ArcMap – even for viewing.
A schema lock is applied on the feature class even when the feature class is just opened for viewing in ArcMap. This ensures the integrity of the data.
ArcSDE geodatabases supports multiple users editing and viewing the same dataset. However, when a schema change is being made, the software applies strict rules, in that only *one* user can be accessing the feature class, table or feature dataset (being changed) in order to make that change. Once the schema change is implemented, all users can continue to view and edit the data simultaneously again.
Other applications that also place a schema lock on the data are:
a) ArcIMS map services
b) ArcGIS Server map services
c) Dekho map services
Thus, in order to make any schema changes to the SDE data, these map services will either need to be stopped or the map service schema lock disabled.
To stop the SOC and SOM services, which in turn will stop all map services, you can manually stop each service via ArcCatalog or the ArcGIS Server Manager.
Or secondly, you can disable the map service schema lock, by setting the tag to false. This tag can be added to the services configuration file (.cfg) for the map service found in
C:\Program Files (x86)\ArcGIS\Server10.0\server\user\cfg
More information can be found via the following ESRI Australia technical blog.
Thus, to get around the “Lock request conflicts with an established lock.” error, it is recommended to perform *all* schema changes after hours when there are less chances of other users editing or viewing the SDE data you are attempting to change.
More information regarding the above can be found via the following ArcGIS Desktop topic: “Schema Locking”: