---
title: Copy/export large tables
description: "When a table is copied or exported, the plugin needs to read and write all table rows. For large tables this might result in a fatal error: ***Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 4096…"
url: "https://docs.legacy.wpdataaccess.com/docs/copy-export-large-tables/"
updated: "2026-03-28"
category: "Data Explorer / Problems & Solutions"
---

# Copy/export large tables

When a table is copied or exported, the plugin needs to read and write all table rows. For large tables this might result in a fatal error:

***Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 4096 bytes)***

One way to solve this issue is to increase **WP_MAX_MEMORY_LIMIT**. But no matter how high you set this value, tables can grow bigger.

To solve this issue and allow the plugin to read and write rows in batches the **query buffer size** was introduced in version 5.2. The **query buffer size** can be defined per table from the **Data Explorer** > **Settings** > **Table Settings** (see image below – click to enlarge).

![](https://docs.legacy.wpdataaccess.com/wp-content/uploads/2026/03/wpda-query-buffer-size.png)

This value is empty by default, which leads to a full table read and write. Enter a sufficient value if you experience issues when copying or exporting large tables. A higher value increases the change of a fatal error. A lower value might increase execution time. There is no **one size fits all**. It depends on the amount of storage used per table row.

When the **query buffer size** is defined, the copy table user interface looks different. A page is presented showing the copy process (see image below – click to enlarge). The number of rows copied will be updated each time a buffer was processed.

![](https://docs.legacy.wpdataaccess.com/wp-content/uploads/2026/03/wpda-copy-in-progress.png)

**Notes**

- Do not close your browser or tab while a copy table or table export is in progress. This is will terminate the process.
- You can cancel a copy table or export job any time. Data already copied or exported is not deleted automatically.
- My largest test was a table containing more then 12.5 million rows. My laptop needed about 5 hours to copy all rows. It worked like a charm. 😉