diff --git a/engine/table/src/main/java/io/deephaven/engine/table/impl/remote/ConstructSnapshot.java b/engine/table/src/main/java/io/deephaven/engine/table/impl/remote/ConstructSnapshot.java
index 1f72098d501..fdbb01bedac 100644
--- a/engine/table/src/main/java/io/deephaven/engine/table/impl/remote/ConstructSnapshot.java
+++ b/engine/table/src/main/java/io/deephaven/engine/table/impl/remote/ConstructSnapshot.java
@@ -1173,6 +1173,18 @@ public static long callDataSnapshotFunction(
      * Invokes the snapshot function in a loop until it succeeds with provably consistent results, or until
      * {@code MAX_CONCURRENT_ATTEMPTS} or {@code MAX_CONCURRENT_ATTEMPT_DURATION_MILLIS} are exceeded. Falls back to
      * acquiring a shared update graph lock for a final attempt.
+     * <p>
+     * The supplied {@link SnapshotControl}'s {@link SnapshotControl#usePreviousValues usePreviousValues} will be
+     * invoked at the start of any snapshot attempt, and its {@link SnapshotControl#snapshotCompletedConsistently
+     * snapshotCompletedConsistently} will be invoked at the end of any snapshot attempt that is not provably
+     * inconsistent.
+     * <p>
+     * If the supplied {@link SnapshotControl} provides a null {@link SnapshotControl#getUpdateGraph UpdateGraph}, then
+     * this method will perform a static snapshot without locks or retrying. In this case, the {@link SnapshotControl}'s
+     * {@link SnapshotControl#usePreviousValues usePreviousValues} must return {@code false},
+     * {@link SnapshotControl#snapshotCompletedConsistently snapshotCompletedConsistently} must return {@code true}, and
+     * the {@link LogicalClock#NULL_CLOCK_VALUE NULL_CLOCK_VALUE} will be supplied to {@code usePreviousValues} and
+     * {@code snapshotCompletedConsistently}.
      *
      * @param logPrefix A prefix for our log messages
      * @param control A {@link SnapshotControl} to define the parameters and consistency for this snapshot
@@ -1190,13 +1202,27 @@ public static long callDataSnapshotFunction(
 
         if (updateGraph == null) {
             // This is a snapshot of static data. Just call the function with no frippery.
+            final boolean controlUsePrev = control.usePreviousValues(LogicalClock.NULL_CLOCK_VALUE);
+            if (controlUsePrev) {
+                throw new SnapshotUnsuccessfulException("Static snapshot requested previous values");
+            }
+
             final boolean functionSuccessful = function.call(false, LogicalClock.NULL_CLOCK_VALUE);
-            Assert.assertion(functionSuccessful, "functionSuccessful");
+            if (!functionSuccessful) {
+                throw new SnapshotUnsuccessfulException("Static snapshot failed to execute snapshot function");
+            }
             if (log.isDebugEnabled()) {
                 final long duration = System.currentTimeMillis() - overallStart;
                 log.debug().append(logPrefix)
                         .append(" Static snapshot function elapsed time ").append(duration).append(" ms").endl();
             }
+
+            // notify control of successful snapshot
+            final boolean controlSuccessful =
+                    control.snapshotCompletedConsistently(LogicalClock.NULL_CLOCK_VALUE, false);
+            if (!controlSuccessful) {
+                throw new SnapshotUnsuccessfulException("Static snapshot function succeeded but control failed");
+            }
             return LogicalClock.NULL_CLOCK_VALUE;
         }
 
diff --git a/server/src/main/java/io/deephaven/server/barrage/BarrageMessageProducer.java b/server/src/main/java/io/deephaven/server/barrage/BarrageMessageProducer.java
index c8ad8192fed..33b48e654dc 100644
--- a/server/src/main/java/io/deephaven/server/barrage/BarrageMessageProducer.java
+++ b/server/src/main/java/io/deephaven/server/barrage/BarrageMessageProducer.java
@@ -501,18 +501,19 @@ public void addSubscription(final StreamObserver<MessageView> listener,
             final Subscription subscription =
                     new Subscription(listener, options, cols, initialViewport, reverseViewport);
 
-            log.debug().append(logPrefix)
-                    .append(subscription.logPrefix)
-                    .append("subbing to columns ")
-                    .append(FormatBitSet.formatBitSet(cols))
-                    .endl();
+            if (log.isDebugEnabled()) {
+                log.debug().append(logPrefix)
+                        .append(subscription.logPrefix)
+                        .append("subbing to columns ")
+                        .append(FormatBitSet.formatBitSet(cols))
+                        .append(" and scheduling update immediately, for initial snapshot.")
+                        .endl();
+            }
 
             subscription.hasPendingUpdate = true;
             pendingSubscriptions.add(subscription);
 
             // we'd like to send the initial snapshot as soon as possible
-            log.debug().append(logPrefix).append(subscription.logPrefix)
-                    .append("scheduling update immediately, for initial snapshot.").endl();
             updatePropagationJob.scheduleImmediately();
         }
     }
@@ -528,6 +529,10 @@ private boolean findAndUpdateSubscription(final StreamObserver<MessageView> list
                         pendingSubscriptions.add(sub);
                     }
 
+                    if (log.isDebugEnabled()) {
+                        log.debug().append(logPrefix).append("Find and update subscription scheduling immediately.")
+                                .endl();
+                    }
                     updatePropagationJob.scheduleImmediately();
                     return true;
                 }
@@ -570,16 +575,20 @@ public boolean updateSubscription(final StreamObserver<MessageView> listener, @N
             }
 
             sub.pendingColumns = cols;
-            log.debug().append(logPrefix).append(sub.logPrefix)
-                    .append("scheduling update immediately, for viewport and column updates.").endl();
+            if (log.isDebugEnabled()) {
+                log.debug().append(logPrefix).append(sub.logPrefix)
+                        .append("scheduling update immediately, for viewport and column updates.").endl();
+            }
         });
     }
 
     public void removeSubscription(final StreamObserver<MessageView> listener) {
         findAndUpdateSubscription(listener, sub -> {
             sub.pendingDelete = true;
-            log.debug().append(logPrefix).append(sub.logPrefix)
-                    .append("scheduling update immediately, for removed subscription.").endl();
+            if (log.isDebugEnabled()) {
+                log.debug().append(logPrefix).append(sub.logPrefix)
+                        .append("scheduling update immediately, for removed subscription.").endl();
+            }
         });
     }
 
@@ -587,7 +596,7 @@ public void removeSubscription(final StreamObserver<MessageView> listener) {
     // Update Processing and Data Recording Methods //
     //////////////////////////////////////////////////
 
-    public DeltaListener constructListener() {
+    public InstrumentedTableUpdateListener constructListener() {
         return parentIsRefreshing ? new DeltaListener() : null;
     }
 
@@ -1340,7 +1349,7 @@ private void updateSubscriptionsSnapshotAndPropagate() {
                 long elapsed = System.nanoTime() - start;
                 recordMetric(stats -> stats.snapshot, elapsed);
 
-                if (SUBSCRIPTION_GROWTH_ENABLED && snapshot.rowsIncluded.size() > 0) {
+                if (SUBSCRIPTION_GROWTH_ENABLED && !snapshot.rowsIncluded.isEmpty()) {
                     // very simplistic logic to take the last snapshot and extrapolate max number of rows that will
                     // not exceed the target UGP processing time percentage
                     PeriodicUpdateGraph updateGraph = parent.getUpdateGraph().cast();
@@ -1364,7 +1373,7 @@ private void updateSubscriptionsSnapshotAndPropagate() {
         }
 
         synchronized (this) {
-            if (growingSubscriptions.size() == 0 && pendingDeltas.isEmpty() && pendingError == null) {
+            if (growingSubscriptions.isEmpty() && pendingDeltas.isEmpty() && pendingError == null) {
                 return;
             }
 
@@ -1450,6 +1459,10 @@ private void updateSubscriptionsSnapshotAndPropagate() {
         if (snapshot != null) {
             try (final BarrageStreamGenerator<MessageView> snapshotGenerator =
                     streamGeneratorFactory.newGenerator(snapshot, this::recordWriteMetrics)) {
+                if (log.isDebugEnabled()) {
+                    log.debug().append(logPrefix).append("Sending snapshot to ").append(activeSubscriptions.size())
+                            .append(" subscriber(s).").endl();
+                }
                 for (final Subscription subscription : growingSubscriptions) {
                     if (subscription.pendingDelete) {
                         continue;
@@ -1488,6 +1501,10 @@ private void updateSubscriptionsSnapshotAndPropagate() {
         }
 
         if (numGrowingSubscriptions > 0) {
+            if (log.isDebugEnabled()) {
+                log.info().append(logPrefix).append("Have ").append(numGrowingSubscriptions)
+                        .append(" growing subscriptions; scheduling next snapshot immediately.").endl();
+            }
             updatePropagationJob.scheduleImmediately();
         }
 
@@ -1882,7 +1899,7 @@ final class ColumnInfo {
                     delta.update.shifted().unapply(modifiedRemaining);
                 }
 
-                if (unfilledAdds.size() > 0) {
+                if (!unfilledAdds.isEmpty()) {
                     Assert.assertion(false, "Error: added:" + coalescer.added + " unfilled:" + unfilledAdds
                             + " missing:" + coalescer.added.subSetForPositions(unfilledAdds));
                 }
@@ -2024,6 +2041,13 @@ private void finalizeSnapshotForSubscriptions(final List<Subscription> subscript
                     || subscription.growingRemainingViewport.firstRowKey() >= parentTableSize
                     || isBlinkTable;
 
+            if (log.isDebugEnabled()) {
+                log.debug().append(logPrefix)
+                        .append(subscription.logPrefix)
+                        .append("finalizing snapshot isComplete=").append(isComplete)
+                        .endl();
+            }
+
             if (isComplete) {
                 // this subscription is complete, remove it from the growing list
                 subscription.isGrowingViewport = false;
@@ -2195,14 +2219,15 @@ public boolean snapshotCompletedConsistently(final long afterClockValue, final b
             }
             if (log.isDebugEnabled()) {
                 log.debug().append(logPrefix)
-                        .append("success=").append(success).append(", validStep=").append(resultValidStep).endl();
+                        .append("success=").append(success).append(", validStep=").append(resultValidStep)
+                        .append(", numSnapshotSubscriptions=").append(snapshotSubscriptions.size()).endl();
             }
             return success;
         }
 
         @Override
         public UpdateGraph getUpdateGraph() {
-            return parent.getUpdateGraph();
+            return parent.isRefreshing() ? parent.getUpdateGraph() : null;
         }
     }