# locking modifier

The locking modifier locks an item for
AQL report processing. The purpose of this modifier is to prevent
transient GFEs when using the AQL list or select commands on large
items that are being simultaneously updated by another user/process.

## Syntax

```
{command} {modifiers} locking
```
Note: Depending upon the item size, amount of memory and
the number of users, the locking modifier can have
an impact on performance. As such, this modifier should only be used
when the file contains items large enough to be stored out of group
and the file is often updated while being read.

## Examples

```
select myfile if A5000 = "big file" locking
```

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Source: https://d3codex.com/access/locking-modifier/ - part of the D3Codex reference.