[DERBY-4537] Update on tables with blob columns streams blobs into memory even when the blobs are not updated/accessed.

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Not A Problem
• Affects Version/s: 10.6.1.0
• Component/s: SQL
• Issue & fix info: Repro attached
• Assignee: Mamta A. Satoor
• Reporter: Mamta A. Satoor
• Created: 05/Feb/10 03:21
• Updated: 05/Feb/10 19:17
• Resolved: 05/Feb/10 19:17

Description

While investigating DERBY-1482, I wrote a simple program to see the behavior of a simple update (without any triggers) of a table with blob columns.

The update is on a non-blob column of a table with blob volumns.

When this update is made with limited heap memory, Derby runs into OOM error.

I tried another table similar to earlier table but with no blob column. An update on that table does not run into OOM when run with same limited heap memory.

I would have expected the update to pass for table with blob column since we are not referencing/updating the blob column. But it appears that we might be streaming in blob column even though it is untouched by the update sql.

I wonder if working on this jira first will make the work for DERBY-1482 any easier or better yet, will it make the problem with DERBY-1482 go away? Will attach a reproducible program for this soon.

Issue Links

• relates to: DERBY-1482 Update triggers on tables with blob columns stream blobs into memory even when the blobs are not referenced/accessed.