# `AshScylla.Search.Storage`
[🔗](https://github.com/ohhi-vn/ash_scylla/blob/main/lib/ash_scylla/search/storage.ex#L1)

CQL schema definitions for the inverted index tables used by the search engine.

Provides functions to create and drop the required tables for the inverted
index. The tables are:

  * `search_post_terms` — maps terms to post IDs with term frequency (TF)
  * `search_post_fields` — stores the analyzed field text for update/delete diffing

## Usage

    AshScylla.Search.Storage.create_tables(MyApp.Repo, "my_keyspace")
    AshScylla.Search.Storage.drop_tables(MyApp.Repo, "my_keyspace")

# `create_post_fields_cql`

```elixir
@spec create_post_fields_cql(String.t()) :: String.t()
```

Returns the CQL statement to create the `search_post_fields` table.

Stores the raw analyzed text per field for each post. Used during updates
to diff old vs new terms and compute additions/removals.

# `create_post_terms_cql`

```elixir
@spec create_post_terms_cql(String.t()) :: String.t()
```

Returns the CQL statement to create the `search_post_terms` table.

This is the primary inverted index table. Each row maps a term to a post_id
with term frequency for ranking.

Partition key: `(term, shard)` to avoid hotspot partitions for common terms.
Clustering key: `post_id` for ordered retrieval.

# `create_tables`

```elixir
@spec create_tables(module(), String.t()) :: :ok | {:error, term()}
```

Creates all search engine tables in the given keyspace.

Returns `:ok` on success or `{:error, reason}` on failure.

# `drop_tables`

```elixir
@spec drop_tables(module(), String.t()) :: :ok | {:error, term()}
```

Drops all search engine tables from the given keyspace.

Returns `:ok` on success or `{:error, reason}` on failure.

# `shard_for`

```elixir
@spec shard_for(String.t(), non_neg_integer()) :: non_neg_integer()
```

Computes the shard number for a given term.

Uses `:erlang.phash2/2` to distribute terms across the configured number
of shards. This prevents hotspot partitions for high-frequency terms.

---

*Consult [api-reference.md](api-reference.md) for complete listing*