## Persistent Indexes
FlexSearch provides a new Storage Adapter where indexes are delegated through persistent storages.
Supported:
- [IndexedDB (Browser)](persistent-indexeddb.md)
- [Redis](persistent-redis.md)
- [SQLite](persistent-sqlite.md)
- [Postgres](persistent-postgres.md)
- [MongoDB](persistent-mongodb.md)
- [Clickhouse](persistent-clickhouse.md)
The `.export()` and `.import()` methods are still available for non-persistent In-Memory indexes.
All search capabilities are available on persistent indexes like:
- Context-Search
- Suggestions
- Cursor-based Queries (Limit/Offset)
- Scoring (supports a resolution of up to 32767 slots)
- Document-Search
- Partial Search
- Multi-Tag-Search
- Boost Fields
- Custom Encoder
- Resolver
- Tokenizer (Strict, Forward, Reverse, Full)
- Document Store (incl. enrich results)
- Worker Threads to run in parallel
- Auto-Balanced Cache (top queries + last queries)
All persistent variants are optimized for larger sized indexes under heavy workload. Almost every task will be streamlined to run in batch/parallel, getting the most out of the selected database engine. Whereas the InMemory index can't share their data between different nodes when running in a cluster, every persistent storage can handle this by default.
Examples Node.js:
- [nodejs-commonjs](../example/nodejs-commonjs):
- [basic-persistent](../example/nodejs-commonjs/basic-persistent)
- [document-persistent](../example/nodejs-commonjs/document-persistent)
- [nodejs-esm](../example/nodejs-esm):
- [basic-persistent](../example/nodejs-esm/basic-persistent)
- [document-persistent](../example/nodejs-esm/document-persistent)
Examples Browser:
- [browser-legacy](../example/browser-legacy):
- [basic-persistent](../example/browser-legacy/basic-persistent)
- [document-persistent](../example/browser-legacy/document-persistent)
- [browser-module](../example/browser-module):
- [basic-persistent](../example/browser-module/basic-persistent)
- [document-persistent](../example/browser-module/document-persistent)
```js
import FlexSearchIndex from "./index.d.ts";
import Database from "./db/indexeddb/index.js";
// create an index
const index = new FlexSearchIndex();
// create db instance with optional prefix
const db = new Database("my-store");
// mount and await before transfering data
await flexsearch.mount(db);
// update the index as usual
index.add(1, "content...");
index.update(2, "content...");
index.remove(3);
// changes are automatically committed by default
// when you need to wait for the task completion, then you
// can use the commit method explicitely:
await index.commit();
```
Alternatively mount a store by index creation:
```js
const index = new FlexSearchIndex({
db: new Storage("my-store")
});
// await for the db response before access the first time
await index.db;
// apply changes to the index
// ...
```
Query against a persistent storage just as usual:
```js
const result = await index.search("gulliver");
```
Auto-Commit is enabled by default and will process changes asynchronously in batch.
You can fully disable the auto-commit feature and perform them manually:
```js
const index = new FlexSearchIndex({
db: new Storage("my-store"),
commit: false
});
// update the index
index.add(1, "content...");
index.update(2, "content...");
index.remove(3);
// transfer all changes to the db
await index.commit();
```
You can call the commit method manually also when `commit: true` option was set.
### Benchmark
The benchmark was measured in "terms per second".
| Store |
Add |
Search 1 |
Search N |
Replace |
Remove |
Not Found |
Scaling |
|
terms per sec |
terms per sec |
terms per sec |
terms per sec |
terms per sec |
terms per sec |
|
| IndexedDB |
123,298 |
83,823 |
62,370 |
57,410 |
171,053 |
425,744 |
No |
| Redis |
1,566,091 |
201,534 |
859,463 |
117,013 |
129,595 |
875,526 |
Yes |
| Sqlite |
269,812 |
29,627 |
129,735 |
174,445 |
1,406,553 |
122,566 |
No |
| Postgres |
354,894 |
24,329 |
76,189 |
324,546 |
3,702,647 |
50,305 |
Yes |
| MongoDB |
515,938 |
19,684 |
81,558 |
243,353 |
485,192 |
67,751 |
Yes |
| Clickhouse |
1,436,992 |
11,507 |
22,196 |
931,026 |
3,276,847 |
16,644 |
Yes |
__Search 1:__ Single term query
__Search N:__ Multi term query (Context-Search)
The benchmark was executed against a single client.