diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/IgniteCacheOffheapManagerImpl.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/IgniteCacheOffheapManagerImpl.java
index bfcdd05db3f2f..923eb153bef7c 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/IgniteCacheOffheapManagerImpl.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/IgniteCacheOffheapManagerImpl.java
@@ -949,7 +949,7 @@ private long allocateForTree() throws IgniteCheckedException {
 
         Set<Integer> missing = new HashSet<>();
 
-        for (Integer p : parts.full()) {
+        for (Integer p : parts.fullSet()) {
             GridCloseableIterator<CacheDataRow> partIter = reservedIterator(p, topVer);
 
             if (partIter == null) {
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionDemander.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionDemander.java
index 87dd49a93221e..5ee97669c93c8 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionDemander.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionDemander.java
@@ -407,7 +407,7 @@ else if (!oldFut.isDone())
                     metrics.clearRebalanceCounters();
 
                     for (GridDhtPartitionDemandMessage msg : assignments.values()) {
-                        for (Integer partId : msg.partitions().full())
+                        for (Integer partId : msg.partitions().fullSet())
                             metrics.onRebalancingKeysCountEstimateReceived(grp.topology().globalPartSizes().get(partId));
 
                         CachePartitionPartialCountersMap histMap = msg.partitions().historicalMap();
@@ -1063,13 +1063,13 @@ public static class RebalanceFuture extends GridFutureAdapter<Boolean> {
                 HashSet<Integer> parts = new HashSet<>(v.partitions().size());
 
                 parts.addAll(v.partitions().historicalSet());
-                parts.addAll(v.partitions().full());
+                parts.addAll(v.partitions().fullSet());
 
                 rebalancingParts.put(k.id(), parts);
 
                 historical.addAll(v.partitions().historicalSet());
 
-                Stream.concat(v.partitions().historicalSet().stream(), v.partitions().full().stream())
+                Stream.concat(v.partitions().historicalSet().stream(), v.partitions().fullSet().stream())
                     .forEach(
                         p -> {
                             queued.put(p, new LongAdder());
@@ -1182,11 +1182,11 @@ public void requestPartitions() {
                     // Make sure partitions scheduled for full rebalancing are cleared first.
                     // Clearing attempt is also required for in-memory caches because some partitions can be switched
                     // from RENTING to MOVING state in the middle of clearing.
-                    final int fullSetSize = d.partitions().full().size();
+                    final int fullSetSize = d.partitions().fullSet().size();
 
                     AtomicInteger waitCnt = new AtomicInteger(fullSetSize);
 
-                    for (Integer partId : d.partitions().full()) {
+                    for (Integer partId : d.partitions().fullSet()) {
                         GridDhtLocalPartition part = grp.topology().localPartition(partId);
 
                         // Due to rebalance cancellation it's possible for a group to be already partially rebalanced,
@@ -1214,7 +1214,7 @@ public void requestPartitions() {
                     }
 
                     // The special case for historical only rebalancing.
-                    if (d.partitions().full().isEmpty() && !d.partitions().historicalSet().isEmpty())
+                    if (d.partitions().fullSet().isEmpty() && !d.partitions().historicalSet().isEmpty())
                         ctx.kernalContext().closure().runLocalSafe((GridPlainRunnable)() -> requestPartitions0(node, parts, d));
                 }
             }
@@ -1238,7 +1238,7 @@ private void requestPartitions0(
                     log.info("Starting rebalance routine [" + grp.cacheOrGroupName() +
                         ", topVer=" + topVer +
                         ", supplier=" + supplierNode.id() +
-                        ", fullPartitions=" + S.toStringSortedDistinct(parts.full()) +
+                        ", fullPartitions=" + S.toStringSortedDistinct(parts.fullSet()) +
                         ", histPartitions=" + S.toStringSortedDistinct(parts.historicalSet()) +
                         ", rebalanceId=" + rebalanceId + ']');
 
@@ -1677,7 +1677,7 @@ public boolean compatibleWith(GridDhtPreloaderAssignments newAssignments) {
                 p0.addAll(partitions);
 
             for (GridDhtPartitionDemandMessage msg : newAssignments.values()) {
-                p1.addAll(msg.partitions().full());
+                p1.addAll(msg.partitions().fullSet());
                 p1.addAll(msg.partitions().historicalSet());
             }
 
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionSupplier.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionSupplier.java
index 85180dff2ef03..3c4a09e671830 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionSupplier.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionSupplier.java
@@ -268,7 +268,7 @@ public void handleDemandMessage(int topicId, UUID nodeId, GridDhtPartitionDemand
             if (sctx == null) {
                 if (log.isDebugEnabled())
                     log.debug("Starting supplying rebalancing [" + supplyRoutineInfo(topicId, nodeId, demandMsg) +
-                        ", fullPartitions=" + S.toStringSortedDistinct(demandMsg.partitions().full()) +
+                        ", fullPartitions=" + S.toStringSortedDistinct(demandMsg.partitions().fullSet()) +
                         ", histPartitions=" + S.toStringSortedDistinct(demandMsg.partitions().historicalSet()) + "]");
             }
             else
@@ -276,7 +276,7 @@ public void handleDemandMessage(int topicId, UUID nodeId, GridDhtPartitionDemand
 
             if (sctx == null || sctx.iterator == null) {
 
-                remainingParts = new HashSet<>(demandMsg.partitions().full());
+                remainingParts = new HashSet<>(demandMsg.partitions().fullSet());
 
                 CachePartitionPartialCountersMap histMap = demandMsg.partitions().historicalMap();
 
@@ -457,7 +457,7 @@ else if (iter.isPartitionMissing(p)) {
 
                     // Mark all remaining partitions as missed to trigger full rebalance.
                     if (iter == null && F.isEmpty(remainingParts)) {
-                        remainingParts = new HashSet<>(demandMsg.partitions().full());
+                        remainingParts = new HashSet<>(demandMsg.partitions().fullSet());
                         remainingParts.addAll(demandMsg.partitions().historicalSet());
                     }
 
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionsFullMessage.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionsFullMessage.java
index 5655ba4a028d6..ead64e48bcff9 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionsFullMessage.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPartitionsFullMessage.java
@@ -371,7 +371,7 @@ public void partitionHistorySuppliers(IgniteDhtPartitionHistorySuppliersMap part
     /**
      *
      */
-    public Collection<Integer> partsToReload(UUID nodeId, int grpId) {
+    public Set<Integer> partsToReload(UUID nodeId, int grpId) {
         if (partsToReload == null)
             return Collections.emptySet();
 
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPreloaderAssignments.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPreloaderAssignments.java
index d21f9ffa1b902..73fbce85deeda 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPreloaderAssignments.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/GridDhtPreloaderAssignments.java
@@ -17,8 +17,6 @@
 
 package org.apache.ignite.internal.processors.cache.distributed.dht.preloader;
 
-import java.util.Collection;
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -150,22 +148,22 @@ public void retainMoving(GridDhtPartitionTopology top) {
                 }
             }
 
-            Collection<Integer> curFull = cntrMap.full();
+            Set<Integer> curFullSet = cntrMap.fullSet();
             Set<Integer> newFullSet = null;
 
-            if (!curFull.isEmpty()) {
+            if (!curFullSet.isEmpty()) {
                 int moving = 0;
 
                 // Fast-path check.
-                for (Integer partId : curFull) {
+                for (Integer partId : curFullSet) {
                     if (top.localPartition(partId).state() == MOVING)
                         moving++;
                 }
 
-                if (moving != curFull.size()) {
+                if (moving != curFullSet.size()) {
                     newFullSet = U.newHashSet(moving);
 
-                    for (Integer partId : curFull) {
+                    for (Integer partId : curFullSet) {
                         if (top.localPartition(partId).state() == MOVING)
                             newFullSet.add(partId);
                     }
@@ -177,7 +175,7 @@ public void retainMoving(GridDhtPartitionTopology top) {
                     newHistMap = curHistMap;
 
                 if (newFullSet == null)
-                    newFullSet = new HashSet<>(curFull);
+                    newFullSet = curFullSet;
 
                 IgniteDhtDemandedPartitionsMap newMap = new IgniteDhtDemandedPartitionsMap(newHistMap, newFullSet);
 
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtDemandedPartitionsMap.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtDemandedPartitionsMap.java
index 91004bb83be79..fe88fce8389b2 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtDemandedPartitionsMap.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtDemandedPartitionsMap.java
@@ -45,9 +45,9 @@ public class IgniteDhtDemandedPartitionsMap implements Serializable, Message {
     private CachePartitionPartialCountersMap historical;
 
     /** Set of partitions that require full rebalancing. */
-    @Order(1)
+    @Order(value = 1, method = "fullSet")
     @GridToStringInclude
-    private Collection<Integer> full;
+    private Set<Integer> full;
 
     /**
      * @param historical Historical partition set.
@@ -165,15 +165,15 @@ public void historicalMap(CachePartitionPartialCountersMap historical) {
     }
 
     /** */
-    public Collection<Integer> full() {
+    public Set<Integer> fullSet() {
         if (full == null)
             return Collections.emptySet();
 
-        return Collections.unmodifiableCollection(full);
+        return Collections.unmodifiableSet(full);
     }
 
     /** */
-    public void full(Collection<Integer> full) {
+    public void fullSet(Set<Integer> full) {
         this.full = full;
     }
 
@@ -195,7 +195,7 @@ public Set<Integer> historicalSet() {
 
     /** */
     public Collection<Integer> all() {
-        return F.concat(false, full(), historicalSet());
+        return F.concat(false, fullSet(), historicalSet());
     }
 
 
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtPartitionsToReloadMap.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtPartitionsToReloadMap.java
index bc965a49926d3..7ebc88c6b4786 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtPartitionsToReloadMap.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtPartitionsToReloadMap.java
@@ -18,10 +18,10 @@
 
 package org.apache.ignite.internal.processors.cache.distributed.dht.preloader;
 
-import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Set;
 import java.util.UUID;
 import org.apache.ignite.internal.Order;
 import org.apache.ignite.internal.util.typedef.F;
@@ -42,9 +42,9 @@ public class IgniteDhtPartitionsToReloadMap implements Message {
     /**
      * @param nodeId Node ID.
      * @param cacheId Cache ID.
-     * @return Collection of partitions to reload.
+     * @return Set of partitions to reload.
      */
-    public synchronized Collection<Integer> get(UUID nodeId, int cacheId) {
+    public synchronized Set<Integer> get(UUID nodeId, int cacheId) {
         if (map == null)
             return Collections.emptySet();
 
@@ -58,7 +58,7 @@ public synchronized Collection<Integer> get(UUID nodeId, int cacheId) {
         if (partsToReload == null)
             return Collections.emptySet();
 
-        return F.emptyIfNull(partsToReload.partitions());
+        return (Set<Integer>)F.emptyIfNull(partsToReload.partitions());
     }
 
     /**
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/PartitionsToReload.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/PartitionsToReload.java
index 023b28ad03f1a..c5a61f730b365 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/PartitionsToReload.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/PartitionsToReload.java
@@ -17,8 +17,8 @@
 
 package org.apache.ignite.internal.processors.cache.distributed.dht.preloader;
 
-import java.util.Collection;
 import java.util.HashSet;
+import java.util.Set;
 import org.apache.ignite.internal.Order;
 import org.apache.ignite.plugin.extensions.communication.Message;
 
@@ -27,21 +27,21 @@ public class PartitionsToReload implements Message {
     /** Type code. */
     public static final short TYPE_CODE = 511;
 
-    /** Collection of partitions to reload. */
+    /** Set of partitions to reload. */
     @Order(value = 0, method = "partitions")
-    private Collection<Integer> parts;
+    private Set<Integer> parts;
 
     /**
-     * @return Collection of partitions to reload.
+     * @return Set of partitions to reload.
      */
-    public Collection<Integer> partitions() {
+    public Set<Integer> partitions() {
         return parts;
     }
 
     /**
-     * @param parts Collection of partitions to reload.
+     * @param parts Set of partitions to reload.
      */
-    public void partitions(Collection<Integer> parts) {
+    public void partitions(Set<Integer> parts) {
         this.parts = parts;
     }
 
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridClientPartitionTopology.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridClientPartitionTopology.java
index 675f891be690c..9ca26f636ae3a 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridClientPartitionTopology.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridClientPartitionTopology.java
@@ -747,7 +747,7 @@ private boolean shouldOverridePartitionMap(GridDhtPartitionMap currentMap, GridD
         @Nullable AffinityTopologyVersion exchangeVer,
         GridDhtPartitionFullMap partMap,
         @Nullable CachePartitionFullCountersMap cntrMap,
-        Collection<Integer> partsToReload,
+        Set<Integer> partsToReload,
         @Nullable Map<Integer, Long> partSizes,
         @Nullable AffinityTopologyVersion msgTopVer,
         @Nullable GridDhtPartitionsExchangeFuture exchFut,
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridDhtPartitionTopology.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridDhtPartitionTopology.java
index 7d6a079f0449b..0c2f415a7a1c1 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridDhtPartitionTopology.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridDhtPartitionTopology.java
@@ -17,7 +17,6 @@
 
 package org.apache.ignite.internal.processors.cache.distributed.dht.topology;
 
-import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -298,7 +297,7 @@ public boolean initPartitionsWhenAffinityReady(AffinityTopologyVersion affVer, G
      *      means full map received is not related to exchange
      * @param partMap Update partition map.
      * @param cntrMap Partition update counters.
-     * @param partsToReload Collection of partitions that need to be reloaded.
+     * @param partsToReload Set of partitions that need to be reloaded.
      * @param partSizes Global partition sizes.
      * @param msgTopVer Topology version from incoming message. This value is not null only for case message is not
      *      related to exchange. Value should be not less than previous 'Topology version from exchange'.
@@ -310,7 +309,7 @@ public boolean update(
         @Nullable AffinityTopologyVersion exchangeResVer,
         GridDhtPartitionFullMap partMap,
         @Nullable CachePartitionFullCountersMap cntrMap,
-        Collection<Integer> partsToReload,
+        Set<Integer> partsToReload,
         @Nullable Map<Integer, Long> partSizes,
         @Nullable AffinityTopologyVersion msgTopVer,
         @Nullable GridDhtPartitionsExchangeFuture exchFut,
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridDhtPartitionTopologyImpl.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridDhtPartitionTopologyImpl.java
index 8227e16172814..b004053ca6f35 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridDhtPartitionTopologyImpl.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/topology/GridDhtPartitionTopologyImpl.java
@@ -1440,7 +1440,7 @@ private boolean shouldOverridePartitionMap(GridDhtPartitionMap currentMap, GridD
         @Nullable AffinityTopologyVersion exchangeVer,
         GridDhtPartitionFullMap partMap,
         @Nullable CachePartitionFullCountersMap incomeCntrMap,
-        Collection<Integer> partsToReload,
+        Set<Integer> partsToReload,
         @Nullable Map<Integer, Long> partSizes,
         @Nullable AffinityTopologyVersion msgTopVer,
         @Nullable GridDhtPartitionsExchangeFuture exchFut,
diff --git a/modules/core/src/test/java/org/apache/ignite/cache/CircledRebalanceTest.java b/modules/core/src/test/java/org/apache/ignite/cache/CircledRebalanceTest.java
index f8fc31de61acb..587ac90acdc50 100644
--- a/modules/core/src/test/java/org/apache/ignite/cache/CircledRebalanceTest.java
+++ b/modules/core/src/test/java/org/apache/ignite/cache/CircledRebalanceTest.java
@@ -169,7 +169,7 @@ public void testCircledNodesRestart(int backups, int nodes) throws Exception {
             if (msg instanceof GridDhtPartitionDemandMessage) {
                 GridDhtPartitionDemandMessage demandMsg = (GridDhtPartitionDemandMessage)msg;
 
-                hasFullRebalance.compareAndSet(false, !F.isEmpty(demandMsg.partitions().full()));
+                hasFullRebalance.compareAndSet(false, !F.isEmpty(demandMsg.partitions().fullSet()));
 
                 return true;
             }
diff --git a/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/FullHistRebalanceOnClientStopTest.java b/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/FullHistRebalanceOnClientStopTest.java
index f95b8bb025b0f..7c84d32cacf2f 100644
--- a/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/FullHistRebalanceOnClientStopTest.java
+++ b/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/FullHistRebalanceOnClientStopTest.java
@@ -246,7 +246,7 @@ public static void cleanup() {
                     }
                 }
 
-                if (!map.full().isEmpty()) {
+                if (!map.fullSet().isEmpty()) {
                     synchronized (mux) {
                         topVersForFull = true;
                     }
diff --git a/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/wal/HistoricalReservationTest.java b/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/wal/HistoricalReservationTest.java
index 0c4c80211a36a..5478ec6e085dc 100644
--- a/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/wal/HistoricalReservationTest.java
+++ b/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/wal/HistoricalReservationTest.java
@@ -194,7 +194,7 @@ public void historicalRebalance(IgniteRunnable someAction) throws Exception {
             if (msg instanceof GridDhtPartitionDemandMessage) {
                 GridDhtPartitionDemandMessage demandMsg = (GridDhtPartitionDemandMessage)msg;
 
-                if (!F.isEmpty(demandMsg.partitions().full()))
+                if (!F.isEmpty(demandMsg.partitions().fullSet()))
                     hasFullRebalance.compareAndSet(false, true);
             }
 
diff --git a/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/wal/WalRebalanceRestartTest.java b/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/wal/WalRebalanceRestartTest.java
index 6b4d5e2552b26..19f6e9f67bd97 100644
--- a/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/wal/WalRebalanceRestartTest.java
+++ b/modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/db/wal/WalRebalanceRestartTest.java
@@ -268,7 +268,7 @@ private void restartRebalance(RebalanceRetrigger retrigger, boolean retriggerAsH
                     if (rebTopVer == null || rebTopVer.before(demandMsg.topologyVersion()))
                         rebTopVer = demandMsg.topologyVersion();
 
-                    if (!F.isEmpty(demandMsg.partitions().full()))
+                    if (!F.isEmpty(demandMsg.partitions().fullSet()))
                         hasFullRebalance.compareAndSet(false, true);
                 }