topic Re: ADLS Gen 2 Delta Tables memory allocation in Data Engineering

ADLS Gen 2 Delta Tables memory allocation

kkumar — Tue, 15 Nov 2022 07:36:07 GMT

if i mount a gen2(ADLS 1) to another gen2(ADLS2) account and create a delta table on ADLS2 will it copy the data or just create something link External table.

i don't want to duplicate the the data.

Re: ADLS Gen 2 Delta Tables memory allocation

youssefmrini — Tue, 15 Nov 2022 15:15:58 GMT

Hey You can't have have nested mounts.

Re: ADLS Gen 2 Delta Tables memory allocation

Pat — Tue, 15 Nov 2022 15:16:44 GMT

Hi @keerthi kumar ,

so basically you can CREATE EXTERNAL TABLES on top of the data stored somewhere - in your case ADLS. Data won't be copied, it will stay where it is, by creating external tables you are actually storing the metadata in your metastore (hive, unity catalog) - where the data is stored, table schema, partitions, etc.

Storing data and being able to query it with different engines it's called decoupling. Decoupling storage from compute allows you to manage cost of storage and compute separately.