Which file size is better 1 GB file size in target or 128 MB or lesser than that

[User16826994223]

Which file size is better 1 GB file size in target or 128 MB or lesser than that , I am interested in knowing concept too.

[sajith_appukutt]

If data is getting appended primarily to the delta table and read ratio is higher than writes ratio - larger file sizes ( 1GB) would be ideal.

However, if your delta table undergoes frequent upserts/merges, having smaller files than the default 1GB can improve MERGE performance as only smaller amounts of data would have to be rewritten.

Check out file size auto tuning for MERGE as well