CassandraQuery
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Defined in: src/persistence/query/CassandraQuery.ts:47
Cassandra/Scylla query. By default, inherits the journal-walking
currentEventsByTag from InMemoryQuery — correct for any
volume but only fast for small-to-medium event corpora because the
default Cassandra schema has no secondary index on the tags
column.
When the journal was constructed with useTagIndex: true, append
dual-writes every (event, tag) pair into an events_by_tag side
table partitioned by (tag) and ordered by (timestamp, persistence_id, sequence_nr). This class overrides
currentEventsByTag to walk that side table — a single
tag-partition scan instead of a full client-side journal sweep
(#44).
Multi-tag filters. The TagFilter operators (all / any /
not, see TagFilter) translate into the side-table query
the same way SqliteQuery does:
allnon-empty → walk the side-table partition forall[0], JS-refine the rest of the filter against the per-rowtagsset carried in the side table. Bounded scan even when the final result is the intersection of several tags.anynon-empty (noall) → walk one partition peranytag and merge by(persistence_id, sequence_nr). N partition scans, sequential, JS-refinesnot.- Only
not(or fully empty) → fall back to the inherited journal scan; only-notqueries don’t have a selective tag to seed the index walk anyway.
Extends
Section titled “Extends”Constructors
Section titled “Constructors”Constructor
Section titled “Constructor”new CassandraQuery(
cassandra):CassandraQuery
Defined in: src/persistence/query/CassandraQuery.ts:51
Parameters
Section titled “Parameters”cassandra
Section titled “cassandra”Returns
Section titled “Returns”CassandraQuery
Overrides
Section titled “Overrides”Methods
Section titled “Methods”allPersistenceIds()
Section titled “allPersistenceIds()”allPersistenceIds(
options?):AsyncIterable<string>
Defined in: src/persistence/query/InMemoryQuery.ts:149
Live stream of every persistence id the journal has ever seen, plus
each new one as it first appears. The stream never completes on
its own — break out of the loop or call return() on the iterator.
This is the fan-out primitive: start a per-entity projection as its
entity shows up, instead of polling currentPersistenceIds and
diffing the result yourself.
Once per stream, not once per journal. A fresh subscription re-emits every id, so a consumer that must not act twice across a restart needs its own checkpoint — the same at-least-once posture the event queries have.
Memory. “Once per stream” is enforced with an in-process set of the ids emitted so far, so a stream over a journal with a million ids holds a million strings for as long as it runs. A lexicographic watermark would be cheaper and wrong: ids are not created in sorted order, so an id that sorts below the mark would be skipped forever, and a fan-out projection that silently never starts is the worst failure this API could have. The catch-up sweep is paged, so the peak is the set plus one page — and a one-shot enumeration that needs no set at all is currentPersistenceIdsPaginated.
Parameters
Section titled “Parameters”options?
Section titled “options?”LiveQueryOptions = {}
Returns
Section titled “Returns”AsyncIterable<string>
Inherited from
Section titled “Inherited from”InMemoryQuery.allPersistenceIds
currentEventsByPersistenceId()
Section titled “currentEventsByPersistenceId()”currentEventsByPersistenceId<
E>(persistenceId,fromSeq,toSeq?):Promise<PersistentEvent<E>[]>
Defined in: src/persistence/query/InMemoryQuery.ts:61
One-shot read of every event for persistenceId whose
sequenceNr >= fromSeq (and <= toSeq if given). Resolves
once with the events known at call time.
Type Parameters
Section titled “Type Parameters”E
Parameters
Section titled “Parameters”persistenceId
Section titled “persistenceId”string
fromSeq
Section titled “fromSeq”number
toSeq?
Section titled “toSeq?”number
Returns
Section titled “Returns”Promise<PersistentEvent<E>[]>
Inherited from
Section titled “Inherited from”InMemoryQuery.currentEventsByPersistenceId
currentEventsByTag()
Section titled “currentEventsByTag()”currentEventsByTag<
E>(filter,fromOffset):Promise<TaggedEvent<E>[]>
Defined in: src/persistence/query/CassandraQuery.ts:56
One-shot read of every event matching filter whose offset is
>= fromOffset. See TagFilter for the operator semantics.
Type Parameters
Section titled “Type Parameters”E
Parameters
Section titled “Parameters”filter
Section titled “filter”fromOffset
Section titled “fromOffset”Returns
Section titled “Returns”Promise<TaggedEvent<E>[]>
Overrides
Section titled “Overrides”InMemoryQuery.currentEventsByTag
currentPersistenceIds()
Section titled “currentPersistenceIds()”currentPersistenceIds():
Promise<string[]>
Defined in: src/persistence/query/InMemoryQuery.ts:127
Snapshot of every persistence id known to the journal, as one array. Resolves once.
Kept, and not deprecated: for a journal with a handful of ids this is simply the convenient shape, and “small journal” is a permanent case rather than a legacy one. It is, however, the only method here with no bound on what it materialises — at a million ids that is a million strings in one allocation. Past the point where the array itself is a cost, use currentPersistenceIdsPaginated, which walks the same data one page at a time.
Returns
Section titled “Returns”Promise<string[]>
Inherited from
Section titled “Inherited from”InMemoryQuery.currentPersistenceIds
currentPersistenceIdsPaginated()
Section titled “currentPersistenceIdsPaginated()”currentPersistenceIdsPaginated(
options?):AsyncIterable<string>
Defined in: src/persistence/query/InMemoryQuery.ts:134
Cursor-paginated snapshot of the persistence ids currently in the
journal, ascending, yielded one at a time. Fetches pageSize ids
per round-trip, so peak memory is one page rather than the whole
set. Completes when the journal is exhausted — unlike
allPersistenceIds it does not wait for new ids.
The cursor is a persistence id, not an opaque token. Resume a
partial walk by passing the last id you handled as
afterPersistenceId. Encoding it would have bought per-backend
freedom that no backend here needs — every one of them enumerates
ids through an index keyed on the id itself — at the price of a
checkpoint no operator can read and no other process can
construct.
Parameters
Section titled “Parameters”options?
Section titled “options?”PaginationOptions = {}
Returns
Section titled “Returns”AsyncIterable<string>
Inherited from
Section titled “Inherited from”InMemoryQuery.currentPersistenceIdsPaginated
eventsByPersistenceId()
Section titled “eventsByPersistenceId()”eventsByPersistenceId<
E>(persistenceId,fromSeq,options?):AsyncIterable<PersistentEvent<E>>
Defined in: src/persistence/query/InMemoryQuery.ts:67
Live stream of every event for persistenceId whose
sequenceNr >= fromSeq. Past events are emitted first
(chronological by sequenceNr), then new events as they are
appended. The stream never completes on its own — break out of
the loop or call return() on the iterator to stop polling.
Type Parameters
Section titled “Type Parameters”E
Parameters
Section titled “Parameters”persistenceId
Section titled “persistenceId”string
fromSeq
Section titled “fromSeq”number
options?
Section titled “options?”LiveQueryOptions = {}
Returns
Section titled “Returns”AsyncIterable<PersistentEvent<E>>
Inherited from
Section titled “Inherited from”InMemoryQuery.eventsByPersistenceId
eventsByTag()
Section titled “eventsByTag()”eventsByTag<
E>(filter,fromOffset,options?):AsyncIterable<TaggedEvent<E>>
Defined in: src/persistence/query/InMemoryQuery.ts:104
Live stream of every event matching filter whose offset is
>= fromOffset. Yields events ordered by (timestamp, persistenceId, sequenceNr). See Offset for offset
semantics — the stream emits the offset alongside the event so
the consumer can persist progress.
filter accepts either a single tag string (back-compat shortcut
for { all: [tag] }) or a TagFilter object that combines
all (intersect), any (union), and not (exclusion) operators.
Type Parameters
Section titled “Type Parameters”E
Parameters
Section titled “Parameters”filter
Section titled “filter”fromOffset
Section titled “fromOffset”options?
Section titled “options?”LiveQueryOptions = {}
Returns
Section titled “Returns”AsyncIterable<TaggedEvent<E>>