Exasol-to-Exasol Import Fails with Parallel Session Token Expiry on Exasol Versions > 8.32+
Details
| Detail name | Value |
|---|---|
| Changelog Number | 26665 |
| Type | Bug |
| Status | Resolved |
| Affected Versions | Exasol 8.32.0 |
| Fix Versions | Exasol 2025.1.2, Exasol 2025.2.0 |
| Resolution Date | 2025-08-20 |
Description
The Exasol-to-Exasol import fails due to the expiration of the parallel session token. This issue arises when both the Source Database (DB A) and Destination Database (DB B) are running versions greater than Exasol 8.32+ (includes Exasol 2025.1+). The token expires if its default lifetime (60 seconds) is exceeded before the required subconnection can be established. The following error message is logged:
Connection exception - Parallel session has expired
Workaround
To bypass the issue temporarily, limit the Exasol-to-Exasol connection string to a single host. For example:
CREATE CONNECTION "EXASOL_TEST" TO 'test.exasol.com:8563' USER '******' IDENTIFIED BY '******';
This assumes that test.exasol.com is not a DNS entry, and the involved Exasol databases are running on multiple nodes.
Fix
The issue has been resolved through an update. However, the fix's implementation depends on your database setup:
Source Database (DB A) refers to DB in which the IMPORT / EXPORT is triggered.
Scenario 1: Fix applied only to the Source Database (DB A)
If the fix is applied to the Source Database (DB A) alone, the issue may persist. To address this:
- Set the database parameter -exaToExaLegacyConnection=1 on DB A.
- Alternatively, update the SQL connection queries to include the parameter LegacyConnection=1.
For detailed guidance, refer to CHANGELOG: Introducing Configurable Legacy Parallel Connection Mode for Exa-to-Exa Operation.
Scenario 2: Fix applied to both Source Database (DB A) and Destination Database (DB B)
If both databases are updated with the fix, the issue will be resolved entirely. As part of this update, the timeout for the parallel session token can be adjusted or disabled using the database parameter parallelSessionTokenTimeout on DB B.
Refer to CHANGELOG: Configurable Parallel Session Token Timeout for Enhanced Subconnection Flexibility for additional details.
