Limit VS Adapter Note Size to 2 million characters

Detail name	Value
Changelog Number	20710
Type	Bug
Status	Resolved
Affected Versions	Exasol 7.1.0, Exasol 8.0.0
Fix Versions	Exasol 8.29.0, Exasol 7.1.29
Resolution Date	2024-07-12

Description

There are limitations of a virtual schema response. Adapter Notes are limited to two million characters. See: https://docs.exasol.com/db/latest/database_concepts/virtual_schema/user_guide.htm#VirtualSchemaLimitations

If adapter notes value in response violates this limitation access to adapter_notes on exa_all_virtual_schemas and exa_dba_virtual_schemas leads to an ‘Internal Server Error’.

Workaround

There are two possibilities:

1. Drop virtual schema
2. Fix the adapter and recreate virtual schema

Fix

• Check the two million characters limit and refuse to create virtual schema if limit is reached.
• There is no change to existing virtual schema adapter and virtual schema. Access to adapter_notes on exa_all_virtual_schemas and exa_dba_virtual_schemas remains corrupted and leads to ‘Internal Server Error’.
• For any newly created virtual schemas from this adapter, exception is triggered.
• After correcting the adapter code, virtual schema can be created and access to adapter_notes on exa_all_virtual_schemas and exa_dba_virtual_schemas works as expected.

SQL_EXA> create virtual schema test_vs2 using test.vs_adapter;
EXA: create virtual schema test_vs2 using test.vs_adapter;
Error: [04000] Maximum adapterNotes length exceeded (2000000) (Session: 1802101755703721984)

Changed behavior