Apache Doris Weekly Troubleshooting Digest: SQL, DDL, and Cluster Operations

SQL Execution

Error E-3113 on long string columns in 2.1.x

Symptom
SELECT statements fail with [E-3113] string column length after upgrading to 2.1.0 or 2.1.1.

Fix
Raise the session variable parallel_pipeline_task_num. On a 32-core / 256 GB node:

SET parallel_pipeline_task_num = 16;  -- or 32

JDBC catalog connection exhaustion

Symptom
Can not connect to jdbc due to error: wait millis 5000, active 10, maxActive 10, creating 0

Fix
Increase the pool size or recreate the catalog:

ALTER CATALOG <catalog_name> 
SET PROPERTIES ('connection_pool_max_size' = '100');

Data Definition

varchar vs. string

Use case Recommendation
Key column Use VARCHAR; STRING is not allowed
Non-key column ≤ 65 533 chars VARCHAR(65533)
Non-key column > 65 533 chars STRING

VARCHAR(65533) reserves at most 65 533 UTF-8 code points; actual storage equals the real data length.

Multi-statement jobs

CREATE JOB in 2.1 supports only one SQL statement per job. A DAG-style task orchestration is on the roadmap.

Asynchronous materialized views

Refresh granularity is currently minute-level. Sub-second refresh is planned via synchronous multi-table materialized views.

Arrow Flight port

The Arrow Flight SQL port can differ from the FE port; any free port is acceptable.

DECIMAL versions after 1.2 → 2.0 upgrade

New tables always use DECIMAL V3. Legacy tables retain their original type; alter the column manually to migrate.

Administration

information_schema restrictions

information_schema exposes virtual views only—no physical files exist—so DROP, ALTER, or INSERT are rejected.

priority_networks with VIP (keepalived)

Given:

  • Physical IP range: 10.0.0.0/24
  • VIP: 10.0.0.10 (managed by nginx+keepalived)
  • Desired subnet mask: 10.0.0.128/25

FE selects the first IP matching priority_networks. If no IP in 10.0.0.128/25 is present, the FE exits. Ensure at least one server IP falls inside the new subnet; otherwise adjust the mask or add a interface.

Replication

Raising the replica count from 3 to 5 on a 5-BE cluster increases fault tolerance (survives two simultaneous BE failures) but does not linearly improve query speed. Use extra replicas primarily for availability, not performance.

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Tags: apache-doris troubleshooting sql DDL cluster-ops

Posted on Sun, 31 May 2026 00:16:23 +0000 by tmharrison