Append tool stalling and failing

[Mark24]

Hi,

I have an ongoing task where I need to load data into a table from an oracle database using a SQL expression.

We used to use the Simple Data Loader in ArcMap and the process worked fine, if a little slow (2-3 hours). I'm currently migrating our processes to ArcGIS Pro and have encountered a problem with the Append tool. After setting up the parameters and hitting 'Run,' the process jumps to 5% complete and then stalls. It then sits at 5% for several hours until eventually crashing Pro.

I've tried appending to data to both a table and to an empty feature class but get the same result.  I've also tried using the Table-to-Table tool and got the old 'ERROR: 999999: Something unexpected cause the tool to fail' message. I'm not overly technical, but I've been trying to work out the issue and have come up empty.

Has anyone else encountered a similar problem when using the tool?

Is it something to do with trying to load data from an sde?

I thought it might have been a compatibility issue with oracle, but we have recently upgrade to 19c and the issue is still occurring. 

I'm currently using Pro 2.9.11

Any thoughts or ideas are greatly appreciated!

[Ed_]

I think for an issue like this it's better to open a ticket with ESRI support.

[EmmaHatcher]

Is your target dataset participating in a relationship class?

I'm running into the same problem in ArcGIS Pro 3.2, but trying to append to a table that participates in multiple many-to-many relationship classes. I verified the unique IDs for the records I am attempting to append don't yet have any related records in other tables. I'm working purely in a local file geodatabase.

Trying to cancel the tool takes even longer (classic...). To resolve, I had to delete the relationship classes from the file geodatabase, and then the append was successful and took less than 30 seconds.