Keyspace Notification

Precautions

• The keyspace notification function is disabled by default because it consumes CPU resources if enabled.
• Do not enable the keyspace notification in high-pressure scenarios. Enabling this function will affect instance performance, and some event notifications may be missed.

Differences from Open-source Redis

1. Configuration methods

   Run CONFIG SET to enable or disable the keyspace notification.

   Config set notify-keyspace-events Ex

   • The keyspace notification is disabled if notify-keyspace-events is empty or does not contain K and E.
     

     • Double quotation marks indicate that the parameter is an empty string.
     • The GeminiDB Redis console client does not allow you to disable the keyspace notification by setting notify-keyspace-events to an empty string.
   • The keyspace notification is enabled if notify-keyspace-events is not empty and is correctly configured. For details, see Table 1.
2. Notification Types

   Table 1 Supported notification types

   Character	Notification	Supported by GeminiDB Redis
   K	Keyspace notification. All notifications are prefixed by __keyspace@__.	Yes
   E	Key event notification. All notifications are prefixed by __keyevent@<db>__ .	Yes
   g	Notifications for generic commands such as DEL, EXPIRE, and RENAME	Yes
   $	Notifications for string commands	Yes
   l	Notifications for list commands	Yes
   s	Notifications for set commands	Yes
   h	Notifications for hash commands	Yes
   z	Notifications for sorted set commands	Yes
   x	EXPIRED event notifications	Yes
   e	EVICT event notifications	N/A
   A	Alias for parameter g$lshzxe	Yes

   As shown in Table 1, EVICT event notifications are not applicable for the current version of GeminiDB Redis.

   The parameter value must contain either K or E. Otherwise, no notifications are issued.

   For example, if you want to subscribe only list-related keyspace notifications, set notify-keyspace-events to Kl.

   The value AKE means all types of notifications are issued.