How add partitions on Glue Job without update table schema?

Question

I created a Glue Table and added description and comments in the columns. I know the schema and it will not change.
I have a Glue Job ETL that adds partitions to this table. I'm trying to do this in two ways, according to the documentation ([https://docs.aws.amazon.com/glue/latest/dg/update-from-job.html]()):

**write_dynamic_frame_from_catalog
**
```
additionalOptions = {"enableUpdateCatalog": True}
additionalOptions["partitionKeys"] = ["region", "year", "month", "day"]
sink = glueContext.write_dynamic_frame_from_catalog(frame=last_transform, database=, table_name=, transformation_ctx="write_sink", additional_options=additionalOptions)
```
**getSink
**
```
sink = glueContext.getSink(
    connection_type="s3", 
    path="",
    enableUpdateCatalog=True,
    partitionKeys=["region", "year", "month", "day"])
sink.setFormat("json")
sink.setCatalogInfo(catalogDatabase=, catalogTableName=)
sink.writeFrame(last_transform)
```

The problem is: the table is updated with the new partitions, but the column comments have been deleted, including the table description.

How to keep the original description and column comments?

Fabrizio · Answer

Hi ,

please note that , as by the documentation page you linked, what you are experiencing is the default behaviuor:

***You can also set the ***`updateBehavior`*** value to ***`LOG`*** if you want to prevent your table schema from being overwritten, but still want to add the new partitions. The default value of ***`updateBehavior`*** is ***`UPDATE_IN_DATABASE`***, so if you don’t explicitly define it, then the table schema will be overwritten.***

The code should look like:

```
additionalOptions = {
    "enableUpdateCatalog": True, 
    "updateBehavior": "LOG"}
additionalOptions["partitionKeys"] = ["partition_key0", "partition_key1"]

sink = glueContext.write_dynamic_frame_from_catalog(frame=last_transform, database=,
    table_name=, transformation_ctx="write_sink",
    additional_options=additionalOptions)
job.commit()
```

How add partitions on Glue Job without update table schema?

Add your answer

Relevant content