larger buffer size for iterateData, avoif native available calls

platform/util-rt/src/com/intellij/util/io/LimitedInputStream.java

@@ -72,6 +72,10 @@ public class LimitedInputStream extends FilterInputStream {
     return Math.min(super.available(), myReadLimit - myBytesRead);
   }
 
+  protected int remainingLimit() {
+    return myReadLimit - myBytesRead;
+  }
+
   public synchronized void mark(final int readLimit) {
     throw new UnsupportedOperationException();
   }

platform/util/src/com/intellij/util/io/PersistentEnumeratorBase.java

@@ -509,7 +509,12 @@ abstract class PersistentEnumeratorBase<Data> implements Forceable, Closeable {
       myKeyStorage.force();
 
       DataInputStream keysStream = new DataInputStream(new BufferedInputStream(new LimitedInputStream(new FileInputStream(keystreamFile()),
-                                                                                                      myKeyStoreFileLength)));
+                                                                                                      myKeyStoreFileLength) {
+        @Override
+        public int available() throws IOException {
+          return remainingLimit();
+        }
+      }, 32768));
       try {
         try {
           while (true) {