[HIVE-18887] Improve preserving column stats for alter table commands

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.0.0
• Component/s: Metastore
• Assignee: Aihua Xu
• Reporter: Aihua Xu
• Created: 07/Mar/18 00:49
• Updated: 21/Mar/18 19:01

Description

We are trying to preserve column stats for certain alter table commands, while seems that current generic approach which compare the old columns against the new columns and update for all the columns may not be efficient . e.g., if we just rename the table, we should be able to update the name itself. COL_STATS table somehow contains DB_Name and Table_Name. If those tables don't have these columns, certain commands don't even need to update these tables.