---
title: NSPersistentStoreConnectionPoolMaxSizeKey
framework: coredata
role: symbol
role_heading: Global Variable
path: coredata/nspersistentstoreconnectionpoolmaxsizekey
---

# NSPersistentStoreConnectionPoolMaxSizeKey

The maximum connection pool size to use on a store that supports concurrent request handling.

## Declaration

```swift
let NSPersistentStoreConnectionPoolMaxSizeKey: String
```

## Discussion

Discussion Values that you specify for this key are of type NSNumber. The connection pool size determines the number of requests a store can handle concurrently, and is a function of how many contexts attempt to access store data at any time. Generally, you don’t set this, and use the default value instead. The default connection pool size is implementation-dependent and may vary by store type or platform.

## See Also

### Constants

- [NSAddedPersistentStoresKey](coredata/nsaddedpersistentstoreskey.md)
- [NSRemovedPersistentStoresKey](coredata/nsremovedpersistentstoreskey.md)
- [NSUUIDChangedPersistentStoresKey](coredata/nsuuidchangedpersistentstoreskey.md)
- [NSPersistentStoreSaveConflictsErrorKey](coredata/nspersistentstoresaveconflictserrorkey.md)
- [NSPersistentStoreUbiquitousTransitionTypeKey](coredata/nspersistentstoreubiquitoustransitiontypekey.md)