OPTIMIZE VORDER for partitioned tables

[amaaiia]

Hi,

I have a lakehouse with some tables under Tables directory.

Some of the tables are partitioned by YEAR, MONTH, DAY, and other tables are not partitioned.

I've applied OPTIMIZE+VORDER to all the tables and I only see changes in the NOT partitioned tables. I see a new parquet file for theese tables, but partitioned tables have not changes in _delta_log directory nor new parquet file.

Why??

[v-pbandela-msft · Accepted solution]

Hi @amaaiia,

Thank you for reaching out in Microsoft Community Forum.

The reason you’re not seeing changes in partitioned tables after running OPTIMIZE and VORDER is:

OPTIMIZE skips partitions that are already optimized, such as large or non-fragmented files.
VORDER only triggers changes if significant data reorganization is required.

please follow below steps to resolve this error;

1. please Check Partition Size using below code
DESCRIBE DETAIL delta.`/lakehouse_path/partitioned_table`

2.Force Optimization on Specific Partitions
OPTIMIZE delta.`/lakehouse_path/partitioned_table` WHERE YEAR = '2024'

3. Please Verify Optimization History
DESCRIBE HISTORY delta.`/lakehouse_path/partitioned_table`

Please continue using Microsoft community forum.

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Regards,
Pavan.