Add global cursor cache

Previously only one cursor per type was cached in the transaction,
meaning that often new cursors were created and discarded.  This
change will make sure we cache more than one cursor per kind in a
local and global pool (similar to KernelTransactions) to minimize
creation and discard of cursors.

community/cypher/cypher/src/test/scala/org/neo4j/cypher/internal/spi/v3_2/TransactionBoundQueryContextTest.scala

@@ -42,7 +42,7 @@ import org.neo4j.kernel.impl.locking.LockTracer
 import org.neo4j.kernel.impl.proc.Procedures
 import org.neo4j.kernel.impl.query.clientconnection.ClientConnectionInfo
 import org.neo4j.kernel.impl.query.{Neo4jTransactionalContext, Neo4jTransactionalContextFactory}
-import org.neo4j.storageengine.api.StorageStatement
+import org.neo4j.storageengine.api.SchemaResources
 import org.neo4j.test.TestGraphDatabaseFactory
 
 import scala.collection.JavaConverters._
@@ -61,7 +61,7 @@ class TransactionBoundQueryContextTest extends CypherFunSuite {
     outerTx = mock[InternalTransaction]
     val kernelTransaction = mock[KernelTransactionImplementation]
     when(kernelTransaction.securityContext()).thenReturn(AUTH_DISABLED)
-    val storeStatement = mock[StorageStatement]
+    val storeStatement = mock[SchemaResources]
     val operations = mock[StatementOperationParts](RETURNS_DEEP_STUBS)
     statement = new KernelStatementImplementation(kernelTransaction, null, storeStatement, new Procedures(), new CanWrite(), LockTracer.NONE)
     statement.initialize(null, operations, PageCursorTracerSupplier.NULL.get())

community/kernel/src/main/java/org/neo4j/kernel/NeoStoreDataSource.java

@@ -86,7 +86,6 @@
 import org.neo4j.kernel.impl.logging.LogService;
 import org.neo4j.kernel.impl.proc.Procedures;
 import org.neo4j.kernel.impl.storageengine.impl.recordstorage.RecordStorageEngine;
-import org.neo4j.kernel.impl.storageengine.impl.recordstorage.StorageStatementFactory;
 import org.neo4j.kernel.impl.store.MetaDataStore;
 import org.neo4j.kernel.impl.store.StoreId;
 import org.neo4j.kernel.impl.store.format.RecordFormatPropertyConfigurator;
@@ -264,7 +263,6 @@ boolean applicable( DiagnosticsPhase phase )
     private final Map<String,IndexImplementation> indexProviders = new HashMap<>();
     private final LegacyIndexProviderLookup legacyIndexProviderLookup;
     private final ConstraintSemantics constraintSemantics;
-    private final StorageStatementFactory storageStatementFactory;
     private final Procedures procedures;
     private final IOLimiter ioLimiter;
     private final AvailabilityGuard availabilityGuard;
@@ -318,7 +316,6 @@ public NeoStoreDataSource(
             AutoIndexing autoIndexing,
             PageCache pageCache,
             ConstraintSemantics constraintSemantics,
-            StorageStatementFactory storageStatementFactory,
             Monitors monitors,
             Tracers tracers,
             Procedures procedures,
@@ -356,7 +353,6 @@ public NeoStoreDataSource(
         this.startupStatistics = startupStatistics;
         this.guard = guard;
         this.constraintSemantics = constraintSemantics;
-        this.storageStatementFactory = storageStatementFactory;
         this.monitors = monitors;
         this.tracers = tracers;
         this.procedures = procedures;
@@ -583,7 +579,7 @@ private StorageEngine buildStorageEngine( PropertyKeyTokenHolder propertyKeyToke
         RecordStorageEngine storageEngine =
                 new RecordStorageEngine( storeDir, config, idGeneratorFactory, eligibleForReuse,
                         idTypeConfigurationProvider, pageCache, fs, logProvider, propertyKeyTokenHolder, labelTokens,
-                        relationshipTypeTokens, schemaStateChangeCallback, constraintSemantics, storageStatementFactory,
+                        relationshipTypeTokens, schemaStateChangeCallback, constraintSemantics,
                         scheduler, tokenNameLookup, lockService, schemaIndexProvider, indexingServiceMonitor,
                         databaseHealth, labelScanStoreProvider, legacyIndexProviderLookup, indexConfigStore,
                         legacyIndexTransactionOrdering, transactionSnapshotSupplier, progressionFactory );

community/kernel/src/main/java/org/neo4j/kernel/api/TransactionHook.java

@@ -19,7 +19,6 @@
  */
 package org.neo4j.kernel.api;
 
-import org.neo4j.storageengine.api.StorageStatement;
 import org.neo4j.storageengine.api.StoreReadLayer;
 import org.neo4j.storageengine.api.txstate.ReadableTransactionState;
 
@@ -35,7 +34,7 @@ interface Outcome
     }
 
     OUTCOME beforeCommit( ReadableTransactionState state, KernelTransaction transaction,
-            StoreReadLayer storeReadLayer, StorageStatement statement );
+            StoreReadLayer storeReadLayer );
     void afterCommit( ReadableTransactionState state, KernelTransaction transaction, OUTCOME outcome );
     void afterRollback( ReadableTransactionState state, KernelTransaction transaction, OUTCOME outcome );
 }

community/kernel/src/main/java/org/neo4j/kernel/api/txstate/TransactionCountingStateVisitor.java

@@ -29,7 +29,6 @@
 import org.neo4j.kernel.impl.api.CountsRecordState;
 import org.neo4j.storageengine.api.NodeItem;
 import org.neo4j.storageengine.api.RelationshipItem;
-import org.neo4j.storageengine.api.StorageStatement;
 import org.neo4j.storageengine.api.StoreReadLayer;
 import org.neo4j.storageengine.api.txstate.ReadableTransactionState;
 import org.neo4j.storageengine.api.txstate.TxStateVisitor;
@@ -40,16 +39,14 @@
 public class TransactionCountingStateVisitor extends TxStateVisitor.Delegator
 {
     private final StoreReadLayer storeLayer;
-    private final StorageStatement statement;
     private final CountsRecordState counts;
     private final ReadableTransactionState txState;
 
-    public TransactionCountingStateVisitor( TxStateVisitor next, StoreReadLayer storeLayer, StorageStatement statement,
+    public TransactionCountingStateVisitor( TxStateVisitor next, StoreReadLayer storeLayer,
             ReadableTransactionState txState, CountsRecordState counts )
     {
         super( next );
         this.storeLayer = storeLayer;
-        this.statement = statement;
         this.txState = txState;
         this.counts = counts;
     }
@@ -65,7 +62,7 @@ public void visitCreatedNode( long id )
     public void visitDeletedNode( long id )
     {
         counts.incrementNodeCount( ANY_LABEL, -1 );
-        storeLayer.nodeGetSingleCursor( statement, id, ReadableTransactionState.EMPTY )
+        storeLayer.nodeGetSingleCursor( id, ReadableTransactionState.EMPTY )
                 .forAll( this::decrementCountForLabelsAndRelationships );
         super.visitDeletedNode( id );
     }
@@ -79,7 +76,7 @@ private void decrementCountForLabelsAndRelationships( NodeItem node )
             return false;
         } );
 
-        storeLayer.degrees( statement, node,
+        storeLayer.degrees( node,
                 ( type, out, in ) -> updateRelationshipsCountsFromDegrees( labelIds, type, -out, -in ) );
     }
 
@@ -94,8 +91,7 @@ public void visitCreatedRelationship( long id, int type, long startNode, long en
     @Override
     public void visitDeletedRelationship( long id )
     {
-        try ( Cursor<RelationshipItem> cursor = storeLayer
-                .relationshipCursor( statement, id, ReadableTransactionState.EMPTY ) )
+        try ( Cursor<RelationshipItem> cursor = storeLayer.relationshipGetSingleCursor( id, ReadableTransactionState.EMPTY ) )
         {
             if ( !cursor.next() )
             {
@@ -125,12 +121,11 @@ public void visitNodeLabelChanges( long id, final Set<Integer> added, final Set<
             }
             // get the relationship counts from *before* this transaction,
             // the relationship changes will compensate for what happens during the transaction
-            storeLayer.nodeGetSingleCursor( statement, id, ReadableTransactionState.EMPTY )
-                    .forAll( node -> storeLayer.degrees( statement, node, ( type, out, in ) ->
+            storeLayer.nodeGetSingleCursor( id, ReadableTransactionState.EMPTY )
+                    .forAll( node -> storeLayer.degrees( node, ( type, out, in ) ->
                     {
                         added.forEach( label -> updateRelationshipsCountsFromDegrees( type, label, out, in ) );
-                        removed.forEach(
-                                label -> updateRelationshipsCountsFromDegrees( type, label, -out, -in ) );
+                        removed.forEach( label -> updateRelationshipsCountsFromDegrees( type, label, -out, -in ) );
                     } ) );
         }
         super.visitNodeLabelChanges( id, added, removed );
@@ -161,6 +156,6 @@ private void updateRelationshipCount( long startNode, int type, long endNode, in
 
     private void visitLabels( long nodeId, PrimitiveIntVisitor<RuntimeException> visitor )
     {
-        storeLayer.nodeGetSingleCursor( statement, nodeId, txState ).forAll( node -> node.labels().visitKeys( visitor ) );
+        storeLayer.nodeGetSingleCursor( nodeId, txState ).forAll( node -> node.labels().visitKeys( visitor ) );
     }
 }

community/kernel/src/main/java/org/neo4j/kernel/impl/api/KernelStatement.java

@@ -26,7 +26,7 @@
 import org.neo4j.kernel.api.txstate.TxStateHolder;
 import org.neo4j.kernel.impl.locking.LockTracer;
 import org.neo4j.kernel.impl.locking.StatementLocks;
-import org.neo4j.storageengine.api.StorageStatement;
+import org.neo4j.storageengine.api.SchemaResources;
 
 public interface KernelStatement extends TxStateHolder, Statement
 {
@@ -38,7 +38,7 @@ public interface KernelStatement extends TxStateHolder, Statement
 
     PageCursorTracer pageCursorTracer();
 
-    StorageStatement storageStatement();
+    SchemaResources schemaResources();
 
     KernelTransaction transaction();
 

community/kernel/src/main/java/org/neo4j/kernel/impl/api/KernelStatementImplementation.java

@@ -44,7 +44,7 @@
 import org.neo4j.kernel.impl.locking.LockTracer;
 import org.neo4j.kernel.impl.locking.StatementLocks;
 import org.neo4j.kernel.impl.proc.Procedures;
-import org.neo4j.storageengine.api.StorageStatement;
+import org.neo4j.storageengine.api.SchemaResources;
 import org.neo4j.storageengine.api.txstate.ReadableTransactionState;
 import org.neo4j.storageengine.api.txstate.WritableTransactionState;
 
@@ -70,7 +70,7 @@
 public class KernelStatementImplementation implements KernelStatement
 {
     private final TxStateHolder txStateHolder;
-    private final StorageStatement storeStatement;
+    private final SchemaResources schemaResources;
     private final AccessCapability accessCapability;
     private final KernelTransactionImplementation transaction;
     private final OperationsFacade facade;
@@ -82,14 +82,14 @@ public class KernelStatementImplementation implements KernelStatement
 
     public KernelStatementImplementation( KernelTransactionImplementation transaction,
                             TxStateHolder txStateHolder,
-                            StorageStatement storeStatement,
+                            SchemaResources schemaResources,
                             Procedures procedures,
                             AccessCapability accessCapability,
                             LockTracer systemLockTracer )
     {
         this.transaction = transaction;
         this.txStateHolder = txStateHolder;
-        this.storeStatement = storeStatement;
+        this.schemaResources = schemaResources;
         this.accessCapability = accessCapability;
         this.facade = new OperationsFacade( transaction, this, procedures );
         this.executingQueryList = ExecutingQueryList.EMPTY;
@@ -224,10 +224,7 @@ public PageCursorTracer pageCursorTracer()
 
     public final void acquire()
     {
-        if ( referenceCount++ == 0 )
-        {
-            storeStatement.acquire();
-        }
+        referenceCount++;
     }
 
     final boolean isAcquired()
@@ -270,15 +267,15 @@ public final void stopQueryExecution( ExecutingQuery executingQuery )
     }
 
     @Override
-    public StorageStatement storageStatement()
+    public SchemaResources schemaResources()
     {
-        return storeStatement;
+        return schemaResources;
     }
 
     private void cleanupResources()
     {
         // closing is done by KTI
-        storeStatement.release();
+        schemaResources.close();
         executingQueryList = ExecutingQueryList.EMPTY;
     }
 

community/kernel/src/main/java/org/neo4j/kernel/impl/api/KernelTransactionImplementation.java

@@ -65,7 +65,7 @@
 import org.neo4j.kernel.impl.transaction.tracing.TransactionTracer;
 import org.neo4j.storageengine.api.StorageCommand;
 import org.neo4j.storageengine.api.StorageEngine;
-import org.neo4j.storageengine.api.StorageStatement;
+import org.neo4j.storageengine.api.SchemaResources;
 import org.neo4j.storageengine.api.StoreReadLayer;
 import org.neo4j.storageengine.api.txstate.ReadableTransactionState;
 import org.neo4j.storageengine.api.txstate.TxStateVisitor;
@@ -117,7 +117,7 @@ public class KernelTransactionImplementation implements KernelTransaction, TxSta
     private TransactionHooks.TransactionHooksState hooksState;
     private StatementOperationParts currentTransactionOperations;
     private final KernelStatementImplementation currentStatement;
-    private final StorageStatement storageStatement;
+    private final SchemaResources schemaResources;
     private final List<CloseListener> closeListeners = new ArrayList<>( 2 );
     private SecurityContext securityContext;
     private volatile StatementLocks statementLocks;
@@ -178,9 +178,9 @@ public KernelTransactionImplementation( StatementOperationContainer operationCon
         this.clock = clock;
         this.transactionTracer = transactionTracer;
         this.cursorTracerSupplier = cursorTracerSupplier;
-        this.storageStatement = storeLayer.newStatement();
+        this.schemaResources = storeLayer.schemaResources();
         this.currentStatement =
-                new KernelStatementImplementation( this, this, storageStatement, procedures, accessCapability, lockTracer );
+                new KernelStatementImplementation( this, this, schemaResources, procedures, accessCapability, lockTracer );
         this.userMetaData = Collections.emptyMap();
     }
 
@@ -535,7 +535,7 @@ private long commit() throws TransactionFailureException
             {
                 try
                 {
-                    hooksState = hooks.beforeCommit( txState, this, storageEngine.storeReadLayer(), storageStatement );
+                    hooksState = hooks.beforeCommit( txState, this, storageEngine.storeReadLayer() );
                     if ( hooksState != null && hooksState.failed() )
                     {
                         TransactionHookException cause = hooksState.failure();
@@ -560,8 +560,7 @@ private long commit() throws TransactionFailureException
                 Collection<StorageCommand> extractedCommands = new ArrayList<>();
                 storageEngine.createCommands(
                         extractedCommands,
-                        txState,
-                        storageStatement,
+                        txState, schemaResources,
                         commitLocks,
                         lastTransactionIdWhenStarted );
                 if ( hasLegacyIndexChanges() )
@@ -806,7 +805,7 @@ public String toString()
     @Override
     public void dispose()
     {
-        storageStatement.close();
+        schemaResources.close();
     }
 
     /**

community/kernel/src/main/java/org/neo4j/kernel/impl/api/KernelTransactions.java

@@ -28,7 +28,6 @@
 
 import org.neo4j.collection.pool.LinkedQueuePool;
 import org.neo4j.collection.pool.MarshlandPool;
-import org.neo4j.function.Factory;
 import org.neo4j.graphdb.DatabaseShutdownException;
 import org.neo4j.graphdb.TransactionFailureException;
 import org.neo4j.kernel.AvailabilityGuard;