---
type: concept
x-llmwiki:
  schemaVersion: "0.1"
  contentHash: f5ceeab320f9b6548b2f6a211c80acb2ea0307f31413aa27c452de95e3a41fa6
  pageDirectory: concepts
  sources:
    - delta_concurrent_append-error-condition-databricks-on-aws.md
  confidence: 0.95
  provenanceState: extracted
  freshnessStatus: unverified
  aliases:
    - allotted-time-exceeded-in-delta-lake
    - ATEIDL
  citations:
    - file: delta_concurrent_append-error-condition-databricks-on-aws.md
title: Allotted Time Exceeded in Delta Lake
description: A sub-error of DELTA_CONCURRENT_APPEND indicating row-level conflict resolution exceeded the allowed time limit, requiring a retry.
tags:
  - delta-lake
  - timeout
  - error-handling
timestamp: "2026-06-19T18:23:15.314Z"
---

# Allotted Time Exceeded in Delta Lake

**Allotted Time Exceeded** is an error condition within the `DELTA_CONCURRENT_APPEND` error class that occurs when Delta Lake's row-level conflict resolution mechanism takes longer than the permitted time limit to resolve a transaction conflict. ^[delta_concurrent_append-error-condition-databricks-on-aws.md]

## Overview

The `ALLOTTED_TIME_EXCEEDED` sub-error is triggered when a concurrent transaction adds data to a Delta table and Delta Lake's automatic conflict resolution logic exceeds the maximum allowed time for processing. This timeout prevents the system from hanging indefinitely during conflict resolution and forces the operation to fail gracefully. ^[delta_concurrent_append-error-condition-databricks-on-aws.md]

## Error Details

This error belongs to the `DELTA_CONCURRENT_APPEND` error class, which has SQLSTATE `2D521` (Invalid Transaction Termination). The full error message indicates:

> Row-level conflict resolution exceeded the allotted time. Please retry the operation.

^[delta_concurrent_append-error-condition-databricks-on-aws.md]

## Common Causes

The `ALLOTTED_TIME_EXCEEDED` error typically occurs under the following conditions:

- **High concurrent write volume:** Multiple transactions attempting to write to the same table simultaneously can overwhelm the conflict resolution mechanism.
- **Large or complex tables:** Tables with many partitions or complex merge conditions may require more time for row-level conflict detection.
- **Resource contention:** Insufficient cluster resources or network latency can prolong conflict resolution times beyond the allotted window.

## Resolution

The primary recommended action when encountering this error is to **retry the operation**. Since the conflict is often transient, a simple retry may succeed on the next attempt. ^[delta_concurrent_append-error-condition-databricks-on-aws.md]

Additional mitigation strategies include:

- **Reducing concurrent writes:** Batch or serialize write operations to the same table when possible.
- **Optimizing queries:** Narrow the scope of write operations using filters or partition hints.
- **Scaling compute resources:** Ensure sufficient cluster capacity to handle the write workload.

## Related Error Conditions

The `DELTA_CONCURRENT_APPEND` error class includes several other sub-errors that may occur in similar scenarios:

- ROW_LEVEL_CHANGES — Concurrent operation modified the same rows
- [WHOLE_TABLE_READ](/concepts/whole-table-readreplace-conflicts.md) — Transaction attempted to read the entire table
- PREDICATES_NEED_REWRITE — Filter predicates could not be applied for conflict detection
- [PARTITIONED_TABLE_WITHOUT_MERGE_SOURCE](/concepts/partitioned-table-merge-conflicts-in-delta-lake.md) — Partitioned table without merge source
- PROTOCOL_CHANGE — Concurrent operation upgraded table protocol

## Related Concepts

- Delta Lake Transaction Conflicts — Overview of concurrency control in Delta Lake
- [Row-Level Conflict Resolution](/concepts/row-level-conflict-resolution.md) — How Delta Lake resolves conflicting writes
- [Optimistic Concurrency Control](/concepts/delta-lake-optimistic-concurrency-control.md) — The underlying concurrency model used by Delta Lake
- DELTA_CONCURRENT_APPEND — The parent error class for concurrent append conflicts

## Sources

- delta_concurrent_append-error-condition-databricks-on-aws.md

# Citations

1. [delta_concurrent_append-error-condition-databricks-on-aws.md](/references/delta_concurrent_append-error-condition-databricks-on-aws-47a87778.md)
