topic Re: Problems with locking tables in File Geodatabase API Questions

Problems with locking tables

teamIgal — Thu, 02 May 2013 07:18:47 GMT

Hello,

I am using file geodatabase api 1.3.
I am not sure what is the proper way to use SetWriteLock() on tables in the GDB.

we are using one instance of the table in the code, and on that instance we read and write data on different places.

before i preform an insert or update on the table i set "SetWriteLock() " and after that "FreeWriteLock()", and still i get exception of "Cannot aquire a lock" when i reach to this line.

Why is that happening?

Thanks,
Igal team

Re: Problems with locking tables

VinceAngelo — Thu, 02 May 2013 10:15:39 GMT

Please provide the smallest possible code sample that exhibits the problem
(preferably using the data samples provided with the API).

- V

Re: Problems with locking tables

LanceShipman — Thu, 02 May 2013 14:43:18 GMT

SetWriteLock and FreeWriteLock modifies locking behavior. If they are not used, a write lock will be set and released for each insert or update. In a loading situation this is very slow. SetWriteLock sets a write lock until the free is called. This is much faster when doing bulk loads. As Vince indicates we need to see a short as possible piece of code that reproduces your issue.

Re: Problems with locking tables

teamIgal — Mon, 13 May 2013 11:58:45 GMT

Thanks for the quick reply.
I was trying to solve the issue by myself but with no luck.

I have difficulties providing code samples, but i will try to explain the situation:

We have MPK file that references a GDB file called Layers.GDB
In the solution we have a mapControl that loads the MPK and shows the layers.

Then we have a singleton class that Opens some of the tables from the GDB. most of the tables are not feature classes and dont contain geography objects.

In the code i have a few table.insert(NewRow) commands. sometimes (Not always) we are getting an exception in these lines with the exception:
FileGDBException was caught
Cannot aquire a lock

Re: Problems with locking tables

teamIgal — Sun, 26 May 2013 05:21:34 GMT

Hi, i am still having the same problems, with no idea how to solve this.

Can you please provide any help?

Thanks,
Team Igal

Re: Problems with locking tables

VinceAngelo — Sun, 26 May 2013 14:53:59 GMT

Please make it possible for us to help you by providing the requested code
(not your application, but a sample using the same calling sequence which
produces the same error with existing [or very simple] data).

- V

Re: Problems with locking tables

AmitSaini — Mon, 09 Sep 2013 09:53:39 GMT

Hi

1) I am opening a feature class as a table to update,
2) Setting the lock,
3) Updating table,
4) Freeing the lock,
5) Closing the table.

There is no issue in this operation.
But to check my updates when I am opening the feature class in Arc Catalog ( in Arc Map also) , Some error is coming.
However after closing the geo database and freeing the objects used , I am able to see the data in both applications.

Is it possible by any means to check the updates in between ?

Re: Problems with locking tables

LanceShipman — Mon, 09 Sep 2013 15:17:34 GMT

What versions of the API and ArcGIS are you using? Can you post your code?

Re: Problems with locking tables

AmitSaini — Tue, 10 Sep 2013 04:42:46 GMT

Esri.FileGDB.Table parcelTable = null;

   parcelTable = geodatabase.OpenTable(argParcelFeatureClassName);

   parcelTable.SetWriteLock();

   rowsParcels = parcelTable.Search(firstColumn, parcelTableWhereClause, RowInstance.Recycle);


   foreach (Esri.FileGDB.Row parcelRow in rowsParcels)
   {

   parcelRow.SetString"ColumnName1","Value1");

   parcelRow.SetDouble("ColumnName2", "Value2");

   parcelTable.Update(parcelRow);

   }

   parcelTable.FreeWriteLock();

         FileGDB API Versions (According to dll properties in Visual Studio 2010)--

Version : 1.3.0.143

         Run Time Version : v4.0.30319

ArcGIS Version : 10.1

Re: Problems with locking tables

AmitSaini — Thu, 26 Sep 2013 12:41:44 GMT

Hello Lance

Do you need more information to answer my question ?

Re: Problems with locking tables

LanceShipman — Sun, 12 Dec 2021 00:06:01 GMT

Try setting the write lock after running the search.

rowsParcels = parcelTable.Search(firstColumn, parcelTableWhereClause, RowInstance.Recycle);

parcelTable.SetWriteLock();