How to index an option field and filter by option value?

[CorrM]

#[table(name = account_session)]
pub struct AccountSession {
    #[primary_key]
    pub connection_id: ConnectionId,
    #[unique]
    pub identity: Identity,
    // Multi session allowed to link to same account(Game client, webclient, etc) at same time.
    #[index(btree)]
    pub account_id: Option<u64>,
    // Currently logged in character, if any.
    pub character_id: Option<u64>,
    pub connected_at: Timestamp,
    pub disconnected_at: Option<Timestamp>,
}

db.account_session().account_id().filter(Some(55u64));:

`Option<u64>` cannot appear as an argument to an index filtering operation
the trait `FilterableValue` is not implemented for `Option<u64>`
The allowed set of types are limited to integers, bool, strings, `Identity`, `ConnectionId`, `Hash` and no-payload enums which derive `SpacetimeType`

db.account_session().account_id().filter(55u64);:

type mismatch resolving `<u64 as FilterableValue>::Column == Option<u64>`
expected enum `Option<u64>`
   found type `u64`
required for `u64` to implement `IndexScanRangeBounds<(Option<u64>,), SingleBound>`

[egormanga]

• Resolves by Implemented FilterableValue for Option<FilterableValue> #4013

[Centril]

Sidenote re. performance: You are pessimizing the index performance of account_id quite bit by adding an Option around it. If you can, it is much preferable from a perf POV to use a sentinel value, e.g., 0 to mean None.

[CorrM]

yes i did that as a workaround. but i think i will stick to your advice for performance.
Thanks for the advice.