CassandraJournal
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Defined in: src/persistence/journals/CassandraJournal.ts:48
Journal backed by Apache Cassandra or ScyllaDB — same CQL protocol, one plug-in serves both. Schema:
- composite partition key
(persistence_id, partition_nr)— keeps individual partitions bounded even for long-lived event streams; - clustering column
sequence_nrfor in-stream ordering; - a small metadata row per persistence_id tracking
max_sequence_nr.
Appends are serialized by a lightweight transaction on the metadata
row: the writer claims its sequence range with a conditional statement
before a single event is written, so two writers that both read head N
can never both proceed (#475). A plain read-check would not be enough —
a Cassandra INSERT is an upsert, so the loser of that race would
silently overwrite the winner’s event instead of being rejected the way
the relational backends’ primary key rejects it. Costs one Paxos
round-trip per append; lightweightTransactions: false trades the
guarantee back for the round-trip.
Implements
Section titled “Implements”Constructors
Section titled “Constructors”Constructor
Section titled “Constructor”new CassandraJournal(
options):CassandraJournal
Defined in: src/persistence/journals/CassandraJournal.ts:60
Parameters
Section titled “Parameters”options
Section titled “options”Returns
Section titled “Returns”CassandraJournal
Accessors
Section titled “Accessors”serializer
Section titled “serializer”Get Signature
Section titled “Get Signature”get serializer():
Serializer<unknown> |undefined
Defined in: src/persistence/journals/CassandraJournal.ts:68
The configured payload serializer — read by CassandraQuery so tag reads decode like the journal.
Returns
Section titled “Returns”Serializer<unknown> | undefined
tagIndexTable
Section titled “tagIndexTable”Get Signature
Section titled “Get Signature”get tagIndexTable():
string
Defined in: src/persistence/journals/CassandraJournal.ts:383
Side-table name used when useTagIndex is set — visible so
CassandraQuery can target it directly.
Returns
Section titled “Returns”string
useTagIndex
Section titled “useTagIndex”Get Signature
Section titled “Get Signature”get useTagIndex():
boolean
Defined in: src/persistence/journals/CassandraJournal.ts:385
Whether dual-writes to the tag-index side table are enabled.
Returns
Section titled “Returns”boolean
Methods
Section titled “Methods”append()
Section titled “append()”append<
E>(persistenceId,events,expectedSeq,tags?):Promise<PersistentEvent<E>[]>
Defined in: src/persistence/journals/CassandraJournal.ts:126
Append events to the stream of persistenceId, enforcing optimistic
concurrency: the current highest sequence number MUST equal expectedSeq
or the call throws JournalConcurrencyError. Returns the written events
with their assigned sequence numbers.
Type Parameters
Section titled “Type Parameters”E
Parameters
Section titled “Parameters”persistenceId
Section titled “persistenceId”string
events
Section titled “events”readonly E[]
expectedSeq
Section titled “expectedSeq”number
readonly string[]
Returns
Section titled “Returns”Promise<PersistentEvent<E>[]>
Implementation of
Section titled “Implementation of”close()
Section titled “close()”close():
Promise<void>
Defined in: src/persistence/journals/CassandraJournal.ts:368
Best-effort teardown; idempotent.
Returns
Section titled “Returns”Promise<void>
Implementation of
Section titled “Implementation of”delete()
Section titled “delete()”delete(
persistenceId,toSeq):Promise<void>
Defined in: src/persistence/journals/CassandraJournal.ts:295
Delete events up to and including toSeq — used when compacting past
a snapshot. Only ever a prefix, so what survives is a suffix that
read still returns contiguously, and sequence numbers never rewind:
highestSeq keeps reporting the high-water mark afterwards.
Parameters
Section titled “Parameters”persistenceId
Section titled “persistenceId”string
number
Returns
Section titled “Returns”Promise<void>
Implementation of
Section titled “Implementation of”highestSeq()
Section titled “highestSeq()”highestSeq(
persistenceId):Promise<number>
Defined in: src/persistence/journals/CassandraJournal.ts:290
Current highest sequence number for persistenceId — 0 if no events exist.
Parameters
Section titled “Parameters”persistenceId
Section titled “persistenceId”string
Returns
Section titled “Returns”Promise<number>
Implementation of
Section titled “Implementation of”persistenceIds()
Section titled “persistenceIds()”persistenceIds():
Promise<string[]>
Defined in: src/persistence/journals/CassandraJournal.ts:312
Persistence IDs currently known to the journal (useful for projections).
Returns
Section titled “Returns”Promise<string[]>
Implementation of
Section titled “Implementation of”persistenceIdsPaginated()
Section titled “persistenceIdsPaginated()”persistenceIdsPaginated(
afterPersistenceId,limit):Promise<string[]>
Defined in: src/persistence/journals/CassandraJournal.ts:341
A clustering-column range over the all_persistence_ids partition.
PRIMARY KEY (tag, persistence_id) makes persistence_id the clustering
column of the single '_all' partition, so AND persistence_id > ? LIMIT ? is a seek into that partition’s sorted run — not the
token(persistence_id) scan over events an earlier sketch of this
called for, which would have paid a coordinator fan-out per page and
handed back ids in ring order, in which no cursor is monotonic.
The single partition is itself a scaling limit at very large id counts —
one replica set owns every id — but that is the shape persistenceIds()
already had, and bucketing it is a schema migration rather than a paging
concern.
Parameters
Section titled “Parameters”afterPersistenceId
Section titled “afterPersistenceId”string | undefined
number
Returns
Section titled “Returns”Promise<string[]>
Implementation of
Section titled “Implementation of”Journal.persistenceIdsPaginated
read()
Section titled “read()”read<
E>(persistenceId,fromSeq,toSeq?):Promise<PersistentEvent<E>[]>
Defined in: src/persistence/journals/CassandraJournal.ts:254
Return the events in [fromSeq, …, toSeq], ascending by sequence
number. toSeq defaults to the current highest sequence number.
Both bounds are inclusive — fromSeq is the first event returned,
not an “after” cursor.
Ordering and contiguity are part of the contract, and replay
enforces them (#122). Consecutive entries must differ by exactly
one, every sequenceNr must be a safe integer ≥ 1, and nothing may
fall outside the requested window. delete compacts a prefix,
never a hole in the middle, so a gap inside the returned slice can
only mean a defect — a missing ORDER BY, a half-written append, a
store someone else can write. replayState raises
JournalIntegrityError instead of folding it, because an actor
that recovers from a shuffled or holed stream reaches a state that
never existed and then fails every later persist with a
JournalConcurrencyError that has no visible cause.
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>[]>
Implementation of
Section titled “Implementation of”start()
Section titled “start()”start():
Promise<void>
Defined in: src/persistence/journals/CassandraJournal.ts:75
Explicitly connect + ensure schema. Called lazily on first use. Single-flight: concurrent callers share one in-flight start; a failed start clears the guard so a later call can retry.
Returns
Section titled “Returns”Promise<void>