---
title: Scripts Painless Regex Enabled
description: Describes what AutoOps detects and surfaces with the Scripts Painless Regex Enabled insight: Painless scripts are allowed to use regular expressions, which Elasticsearch turns off by default because some patterns are extremely CPU- and memory-heavy.
url: https://docs-v3-preview.elastic.dev/elastic/autoops-insights/tree/main/elasticsearch/scripts_painless_regex_enabled
products:
  - Elastic Cloud Enterprise
  - Elastic Cloud Hosted
  - Elastic Cloud on Kubernetes
  - Elasticsearch
applies_to:
  - Elastic Cloud Hosted: Generally available
  - Elastic Cloud on Kubernetes: Generally available
  - Elastic Cloud Enterprise: Generally available
  - Self-managed Elastic deployments: Generally available
---

# Scripts Painless Regex Enabled
Painless scripts are allowed to use regular expressions, which Elasticsearch turns off by default because some patterns are extremely CPU- and memory-heavy. A poorly written regex in an ingest pipeline, update-by-query, or runtime field can slow the whole node and amplify search or indexing latency.
<note>
  For a complete list of insights, refer to [AutoOps insights](https://docs-v3-preview.elastic.dev/elastic/autoops-insights/tree/main/elasticsearch).
</note>


## Insight details


| Field     | Value                        |
|-----------|------------------------------|
| Component | Elasticsearch                |
| Severity  | Medium                       |
| Scope     | Cluster                      |
| Domains   | performance, security-safety |


## Example: What you might see in AutoOps

The following is an example of what you might see when this insight is triggered. Real insights use live data and links from your deployment or cluster.

### Regular expressions are allowed to run in Painless scripts


#### What was detected

_No description available._

#### Recommendations

<note>
  AutoOps shows different recommendations depending on how their conditions match your deployment or cluster.
</note>

<dropdown title="Disable Painless regex scripting">
  **Condition**: Always shown for this insight.Set `script.painless.regex.enabled` to `false` in `elasticsearch.yml` on every node, then restart each node. The default is `limited`, which restricts regex complexity.
</dropdown>


#### Background and impact

Impact: Some scripts containing regular expressions can be extremely slow and require a great deal of resources to run, which can cause performance issues.
Regex (short for regular expression) refers to a technique for searching using a sequence of characters defining a search pattern.
Regex must be used with care in painless scripts, since some expressions can be extremely slow and require a great deal of resources to run. For this reason regex is turned off by default in painless scripts. Keep in mind that the use of regex — if properly implemented — is perfectly legitimate. Since 7.10, it is also possible to keep regular expression enabled but limit their complexity to prevent consuming too many resources.