Paging¶

Automatic paging uses ClusterConfig.PageSize, or the value set by Query.PageSize. Very small pages increase round trips; the default is 5000.

For manual paging, keep the returned page state opaque and pass it only to the same query and protocol version:

var pageState []byte
var eventID gocql.UUID
var payload string

for {
	iter := session.Query(
		"SELECT event_id, payload FROM events WHERE account_id = ?",
		accountID,
	).PageSize(100).PageState(pageState).Iter()

	nextPageState := iter.PageState()
	for iter.Scan(&eventID, &payload) {
		// Process the row.
	}
	if err := iter.Close(); err != nil {
		return err
	}
	if len(nextPageState) == 0 {
		break
	}
	pageState = nextPageState
}

A server can return an empty intermediate page for range or ALLOW FILTERING queries. Use Iter.Scan, Iter.LastPage, or the returned page state instead of treating an empty page as completion.

Page state contains primary-key data. Protect it with authenticated encryption before exposing it in a URL or another untrusted location. Never modify it or reuse it with a different statement or protocol version.