Troubleshooting¶

Alation Cloud Service Applies to Alation Cloud Service instances of Alation

Customer Managed Applies to customer-managed instances of Alation

Core Connector Core connectors are included with all Alation platform tiers (subject to each tier’s connector limits) and are fully supported by Alation.

Log Location¶

Refer to Troubleshoot OCF Connectors.

Connection via Native Network Encryption (NNE) fails¶

Make sure that you have the required permissions.

Grant permission on tables v_$session_connect_info and v_$mystat to the user as these are the corresponding synonyms too.
If you can’t grant permissions directly, run the following commands:
GRANT SELECT ON v_$mystat TO <user> GRANT SELECT ON v_$session_connect_info TO <user>

Run the following commands:

select network_service_banner from v$session_connect_info where sid in (select distinct sid from v$mystat);

Verify the output for the queries mentioned above.

If encryption or checksum is enabled:

TCP/IP NT Protocol Adapter for Linux: Version 19.0.0.0.0 - Production
Encryption service for Linux: Version 19.0.0.0.0 - Production
AES256 Encryption service adapter for Linux: Version 19.0.0.0.0 - Production
Crypto-checksumming service for Linux: Version 19.0.0.0.0 - Production
SHA1 Crypto-checksumming service adapter for Linux: Version 19.0.0.0.0 - Production

If encryption or checksum is disabled:

TCP/IP NT Protocol Adapter for Linux: Version 19.0.0.0.0 - Production
Encryption service for Linux: Version 19.0.0.0.0 - Production
Crypto-checksumming service for Linux: Version 19.0.0.0.0 - Production

MDE Encounters an Error “ORA-01795: Maximum number of expressions in a list is 1000”¶

Metadata extraction (MDE) on an Oracle data source encounters the error ORA-01795: Maximum number of expressions in a list is 1000.

Problem¶

You are running metadata extraction (MDE) on an Oracle data source. You have either:

configured MDE using custom queries, or
enabled selective extraction by choosing specific schemas.

When the user starts MDE, the job encounters this error. On the connector Settings > Metadata Extraction > Job History tab, the job’s run report shows the Oracle database error:

ORA-01795: Maximum number of expressions in a list is 1000

The metadata extraction does not complete, and no metadata updates are ingested into the catalog.

Cause¶

Oracle databases limit the number of expressions allowed in the IN clause to 1,000. This limitation causes the error in either of the following situations:

A custom MDE query includes an IN clause with more than 1,000 values.
Selective extraction includes more than 1,000 schemas, resulting in a query that exceeds Oracle’s expression limit.

This behavior is due to an Oracle database constraint, not an Alation limitation.

Solution¶

Follow the steps below depending on how your MDE is configured:

If using custom extraction queries:

Modify your query to avoid exceeding the 1,000 expression limit. Options include:
1. Split large IN clauses into multiple smaller clauses, each containing 1,000 values or fewer.
2. Replace the IN clause with an alternative pattern such as EXISTS or JOIN.
3. Use other filtering strategies that do not require a long value list.

If using selective extraction:

Reduce the number of selected schemas to 1,000 or fewer.
If you must extract more than 1,000 schemas, consider grouping them and running MDE in multiple batches.

3. Re-run metadata extraction

After correcting the MDE configuration, re-run MDE from the Metadata Extraction tab.