Databricks upon inserting delta table data inserts into folders in Dev

[NandaKishoreI]

We have a Delta Table in Databricks. When we are inserting data into the Delta Table, in the storage account, it creates folders like: 05, 0H, 0F, 0O, 1T,1W, etc... and adds the parquet files there.

We have not defined any partitions. We are inserting data using following code:

df.write\

                    .mode('append')\

                    .option("mergeSchema", "true")\

                    .option("ignoreLeadingWhiteSpace","false") \

                    .option("ignoreTrailingWhiteSpace","false") \

                    .format('delta').save(prepped_path)

The Table Properties are:

delta.columnMapping.mode=name
delta.minReaderVersion=2
delta.minWriterVersion=6

delta.columnMapping.maxColumnId=18

[Kaniz_Fatma · Accepted solution]

Hi @NandaKishoreI, 

• The folder structure you’re observing is typical for Delta tables. Each folder corresponds to a specific transaction log or checkpoint. These folders contain the Parquet files that represent the data at different points in time.
• The alphanumeric folder names are based on the hexadecimal representation of the transaction log version or checkpoint.
• Even without explicitly defining partitions, Delta Tables automatically organize data into these folders to support efficient query execution and time travel features.

[Rishabh_Tiwari]

Hi @NandaKishoreI ,

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