Table of Contents

Materialised view options

Part of Configuration.

Materialised views are configured per view name on a separate options type, LatticeViewOptions, not on LatticeOptions. Set a per-view override with ConfigureLatticeView(viewName, ...). There is no no-name overload: each view resolves its options by its view name, so a default for every view goes through the standard options API as siloBuilder.Services.ConfigureAll<LatticeViewOptions>(...) (a plain Configure<LatticeViewOptions>(...) reaches only the unnamed instance):

siloBuilder.ConfigureLatticeView("adults", options =>
{
    options.BatchSize = 512;
    options.CoalesceWindow = TimeSpan.FromMilliseconds(100);
});
Option Default Meaning
BatchSize 256 Maximum WAL entries read from each source partition per drain pass. Must be positive.
CoalesceWindow 50 ms Period of the background drain timer. Must be greater than zero and at most 0xFFFFFFFE milliseconds (about 49.7 days), the longest period a grain timer accepts.
SourceIdentityBackstopInterval 30 s Safety-net interval after which the maintainer re-resolves its source tree's physical identity from the registry when no alias-change notification has arrived. In steady state the source binding is event-driven, so this backstop only covers a missed push. Must be greater than zero.
AggregationFanout 1 Aggregation views only: shards each group's accumulator into this many sub-accumulators hashed on the source key, merged at read. Must be at least 1.
AggregationMaxGroupEntries 0 Aggregation views only: when greater than zero, bounds each Min / Max / SetUnion group shard (approximate mode). 0 keeps every group exact. Must not be negative.
MaxStagedTransactions 1024 Maximum in-flight atomic-write transactions buffered before the backstop forces a rebuild. Must be at least 1.
MaxStagedBytes 64 MiB Maximum buffered prepared-entry payload before the backstop forces a rebuild. Must be at least 1.
ReadHandleCacheTtl 1 s How long an ILatticeView handle caches the resolved live view tree id. Bounds the post-swap read-staleness window. Must be greater than zero.
OldGenerationReclaimGrace 5 s How long a swapped-out view tree is retained before reclamation. Must exceed ReadHandleCacheTtl.
CrossTreeReadinessTimeout 5 s Cross-tree atomic visibility only: how long a completed cross-tree batch waits for every present participant view before degrading to per-tree atomicity. Must be greater than zero.
ReplicationMode DeriveLocally How the view tree is made available across clusters. ShipView requires the replication package.
ShipViewProducerClusterId null Required only when ShipView replicates both source and view trees. The stable, case-sensitive replication cluster id of the single producer. When set it must be non-empty and ReplicationMode must be ShipView (enforced by the options validator); the replication topology guards also reject a value on a view whose source tree is not replicated.
MaxLagBudget 0 Maximum committed-but-unapplied source entries before the view is force-evicted (WAL unpinned and rebuilt). 0 disables eviction. Must not be negative.
LagEvictionCooldown 30 s Minimum interval between two lag-budget evictions of the same view. Has no effect when MaxLagBudget is 0.
ObeySourceBackpressure true Whether the maintainer throttles its own drain when the source tree's WAL is under saturation back-pressure (smaller batch + deferred ticks). The maintainer reads the signal under the source tree id the view was declared with, while the signal is sampled under the id of the write-ahead log the source's writes land in, so on an aliased source tree (after a resize, a shadow-cutover restore, a schema remediation or an operator-set alias) it never sees back-pressure and drains at full rate (see Resolution and scope). Set to false to always drain at full rate.
ThrottledBatchRatio 0.5 Fraction of BatchSize drained per pass while the source is Throttled. Must be within [0, 1] (enforced by the options validator); the effective batch is clamped to [1, BatchSize].
ThrottledPauseMs 50 Milliseconds background drain ticks are skipped after a pass that saw a Throttled source. <= 0 disables the deferral.
SaturatedBatchSize 16 Drip-feed batch drained per pass while the source is Saturated. Must be at least 1 (enforced by the options validator); the effective batch is clamped to BatchSize.
SaturatedPauseMs 500 Milliseconds background drain ticks are skipped after a pass that saw a Saturated source. <= 0 disables the deferral.
HistoryHybridFullValueWindow 5 minutes Durable history views under HistoryRetentionMode.Hybrid only: the maximum apply-time age of a revision for which full LWW value bytes are kept; an older revision (drained from a backlog or a catch-up replay) is shaped to metadata only. A non-positive value degrades hybrid to metadata-only. See History views.

See Materialised views for the full behaviour of each option, including what registrations a view needs (AddLattice + AddLatticeViews, the latter folding in AddWalCursorRegistry).