Search and query Active-Active databases
Starting with RediSearch 2.x, supported in Redis Enterprise Software (RS) 6.0 and later, you can enable search and query for Active-Active databases at the time of creation.
You can run search operations on any instance of an Active-Active database.
How it works
- Create an Active-Active database with RediSearch 2.x enabled.
- Create the index on each instance of the database.
- If you are using synonyms, you need to add them to each replica.
- The index is maintained by each instance outside of the database keyspace, so only updates to the hashes in the databases are synchronized.
Command compatibility
Active-Active databases do not support the following search and query commands:
Example
Here’s an example to help visualize Active-Active search and query:
| Time | Description | CRDB Instance1 | RediSearch Instance 1 | CRDB Instance 2 | RediSearch Instance 2 |
|---|---|---|---|---|---|
| t0 | Create the index on each instance | FT.CREATE idx …. | FT.CREATE idx …. | ||
| t1 | Add doc1 as a hash on instance 1; RediSearch indexes doc1 on instance 1 | HSET doc1 field1 “a” | (Index doc1 field1 “a”) | ||
| t2 | Add doc2 as a hash on instance 2; RediSearch indexes doc2 on instance 2 | HSET doc1 field2 “b” | (Index doc1 field2 “b”) | ||
| t3 | Searching for “a” in each instance only finds the result in instance 1 | FT.Search idx “a” 1) 1 2) doc1 | FT.Search idx “a” 1) 0 | ||
| t4 | Active-Active synchronization | - Sync - | - Sync - | ||
| t5 | Both hashes are found in each instance | HGETALL doc1 1) “field2” 2) “b” 3) “field1” 4) “a” | HGETALL doc1 1) “field2” 2) “b” 3) “field1” 4) “a” | ||
| t6 | Searching for “a” in each instance finds both documents | FT.Search idx “a” 1) 1 2) doc1 | FT.Search idx “a” 1) 1 2) doc1 |
The practical result is that you have a geo-distributed database with a high level of consistency that can also run search operations on any instance.