Avoid Duplicate TXT Records When Replacing TXT Values Through the API

TXT records can contain multiple values for the same host name. 

When replacing TXT record content through the UltraDNS API, use PUT instead of PATCH so the TXT record set is replaced with the values provided in the request.

What This Means

A TXT record is different from record types such as CNAME. 

A CNAME host name must uniquely identify the record, but multiple TXT values can exist under the same host name.

Because more than one TXT value can share the same host name, a request that changes the Points To value or TXT value may not uniquely identify which existing TXT value should be updated.

Why Duplicate TXT Records Can Be Created

If an API request changes the TXT value without replacing the full TXT record set, UltraDNS may treat the submitted value as an additional TXT value for the same host name instead of replacing the existing value.

This can result in multiple TXT entries being present under the same host name.

How to Replace TXT Record Content

When the intent is to replace existing TXT record content, use PUT.

A PUT request replaces the existing TXT record set with the TXT values included in the request.

Do not use PATCH when the intended outcome is to replace an existing TXT value.

TTL-Only Changes

A TTL-only change behaves differently. A TXT RRSet has a single TTL value, so updating only the TTL updates the existing TXT record set instead of adding another TXT value.

Expected Outcome

After using PUT with the intended TXT values, the TXT record set contains the values supplied in the request.

After changing only the TTL, the existing TXT record set remains in place and the TTL value is updated.

Important Notes

• Use PUT when replacing TXT record content through the API.
• Do not use PATCH when the intended result is to replace an existing TXT value.
• Multiple TXT values can share the same host name.
• A TTL-only update changes the TXT RRSet TTL and does not add another TXT value.