Struct ReadTxn 

pub struct ReadTxn<'db> { /* private fields */ }

Public read transaction. Acquired by crate::Db::read_transaction.

Carries only the obj-core read-side handle — the writer’s live Catalog is NOT held by a ReadTxn because reads consult the snapshot-pinned catalog root via obj_core::Catalog::lookup_via_snapshot (M6 #53), not the live Catalog.tree.root.

M11 #93: a ReadTxn MAY also carry one AttachedReadCtx per attached database registered on the calling crate::Db. The per-attached snapshots are pinned at txn-begin time and released when the ReadTxn drops; reads against <namespace>.<collection> route through them.

Implementations

impl<'db> ReadTxn<'db>

pub fn collection<T: Document>(&self) -> Result<Collection<'_, T>>

Open a typed handle to the collection T lives in.

Read-only: returns Error::CollectionNotFound if the collection has never been registered AT THE SNAPSHOT’S PINNED LSN.

If T::COLLECTION is of the form <namespace>.<name>, the txn dispatches against the attached database registered under <namespace> instead of the calling Db.

Errors

• Error::CollectionNotFound if T::COLLECTION is not registered in the catalog as-of the snapshot’s pinned LSN.
• Error::CollectionNamespaceUnknown if T::COLLECTION carries a namespace prefix that is not attached.
• Error::Busy if the pager / catalog mutex is poisoned.