topic Re: Delta table cannot be previewed in the Data UI in Data Engineering

Delta table cannot be previewed in the Data UI

chanansh — Sun, 15 Jan 2023 11:49:30 GMT

I have saved a delta table which I can read using `spark.table(table_name)`. However, when I go to the "Data" panel in databricks I get an error when I choose that table.

An error occurred while fetching table: <table_name>

com.databricks.backend.common.rpc.DatabricksExceptions$SQLExecutionException: org.apache.spark.sql.AnalysisException: Incompatible format detected.

A transaction log for Databricks Delta was found at `<path>/_delta_log`,

but you are trying to read from `<path>` using format("parquet"). You must use

'format("delta")' when reading and writing to a delta table.

To disable this check, SET spark.databricks.delta.formatCheck.enabled=false

To learn more about Delta, see https://docs.databricks.com/delta/index.html

Re: Delta table cannot be previewed in the Data UI

chanansh — Tue, 17 Jan 2023 09:43:26 GMT

I don't know. The way I have saved the table was with autoloader as follows:

I am saving a structure stream into a table using:

```

.writeStream

.format("delta") # <-----------

.option("checkpointLocation", checkpoint_path)

.option("path", output_path)

.trigger(availableNow=True)

.toTable(table_name, format='delta'))

```

Yet the produced table seems not to be a delta one as I cannot read it in Redash, nor the Data preview feature in databricks. Moreover if I run delta.DeltaTable.isDeltaTable(spark, TABLE_NAME) it returns False.

Re: Delta table cannot be previewed in the Data UI

jose_gonzalez — Tue, 25 Apr 2023 23:02:06 GMT

did you wrote any data? did your micro-batch process any data? you can check if you do "%sql describe extended <delta_table_name>" in the output you will find the path to the location in which your data is located. Then you can try to list the data in that path. You need to have a _delta_log file in there

Re: Delta table cannot be previewed in the Data UI

Debayan — Tue, 17 Jan 2023 05:40:31 GMT

Hi, It can be an issue with Hive Metastore. Could you please recheck the configuration and also let us know if you are using external metastore?