Fix dynamic table cpu burn #10472

Signed-off-by: Daniel Kec <[email protected]>

Author: danielkec

http/http2/src/main/java/io/helidon/http/http2/Http2Headers.java

@@ -1124,7 +1124,7 @@ void write(BufferData buffer) {
 
     /**
      * There is one dynamic table for inbound headers and one for outbound headers for each connection.
-     * This is to minimize size of headers on the transport.
+     * This is to minimize the size of headers on the transport.
      * The table caches header names and values and then uses indexes only when transferring headers over network.
      */
     public static class DynamicTable {
@@ -1175,8 +1175,8 @@ void maxTableSize(long number) {
             }
             this.maxTableSize = number;
             if (maxTableSize == 0) {
-                currentTableSize = 0;
                 headers.clear();
+                currentTableSize = 0;
             }
             while (maxTableSize < currentTableSize) {
                 evict();
@@ -1193,7 +1193,7 @@ int add(HeaderName headerName, String headerValue) {
 
             while ((currentTableSize + size) > maxTableSize) {
                 evict();
-                if (currentTableSize <= 0) {
+                if (maxTableSize - currentTableSize < size) {
                     throw new Http2Exception(Http2ErrorCode.COMPRESSION,
                                              "Cannot add header record, max table size too low. "
                                                      + "current size: " + currentTableSize + ", max size: " + maxTableSize + ","
@@ -1244,6 +1244,7 @@ private IndexedHeaderRecord find(HeaderName headerName, String headerValue) {
 
         private void evict() {
             if (headers.isEmpty()) {
+                currentTableSize = 0;
                 return;
             }
             DynamicHeader removed = headers.remove(headers.size() - 1);

http/http2/src/test/java/io/helidon/http/http2/DynamicTableTest.java

@@ -67,6 +67,46 @@ void testIssue10472() {
         table.maxTableSize(0L);
     }
 
+    @Test
+    void testIssue10472addOnlyOneFit() {
+        Http2Settings settings = Http2Settings.builder()
+                .add(Http2Setting.HEADER_TABLE_SIZE, 45L)
+                .build();
+
+        Http2Headers.DynamicTable table = Http2Headers.DynamicTable.create(settings);
+        table.add(HeaderNames.create("a"), "aa"); // 35
+        testRecord(table, Http2Headers.StaticHeader.MAX_INDEX + 1, "a", "aa");
+        table.add(HeaderNames.create("b"), "b"); // 34
+
+        testRecord(table, Http2Headers.StaticHeader.MAX_INDEX + 1, "b", "b");
+
+        table.add(HeaderNames.create("c"), "c"); // 34
+        table.add(HeaderNames.create("dddd"), "ddddd"); // 41
+
+        testRecord(table, Http2Headers.StaticHeader.MAX_INDEX + 1, "dddd", "ddddd");
+    }
+
+    @Test
+    void testIssue10472addOnlyTwoFit() {
+        Http2Settings settings = Http2Settings.builder()
+                .add(Http2Setting.HEADER_TABLE_SIZE, 75L)
+                .build();
+
+        Http2Headers.DynamicTable table = Http2Headers.DynamicTable.create(settings);
+        table.add(HeaderNames.create("a"), "aa"); // 35
+        testRecord(table, Http2Headers.StaticHeader.MAX_INDEX + 1, "a", "aa");
+        table.add(HeaderNames.create("b"), "b"); // 34
+
+        testRecord(table, Http2Headers.StaticHeader.MAX_INDEX + 1, "b", "b");
+        testRecord(table, Http2Headers.StaticHeader.MAX_INDEX + 2, "a", "aa");
+
+        table.add(HeaderNames.create("c"), "c"); // 34
+        table.add(HeaderNames.create("dddd"), "ddddd"); // 41
+
+        testRecord(table, Http2Headers.StaticHeader.MAX_INDEX + 1, "dddd", "ddddd");
+        testRecord(table, Http2Headers.StaticHeader.MAX_INDEX + 2, "c", "c");
+    }
+
     private void testRecord(Http2Headers.DynamicTable table,
                             int index,
                             String expectedName,

tests/integration/h2spec/pom.xml

@@ -49,11 +49,11 @@
         </dependency>
         <dependency>
             <groupId>io.helidon.logging</groupId>
-            <artifactId>helidon-logging-jul</artifactId>
+            <artifactId>helidon-logging-slf4j</artifactId>
         </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-jdk14</artifactId>
+            <artifactId>slf4j-simple</artifactId>
         </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>

tests/integration/h2spec/src/test/java/H2SpecIT.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2024, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,6 +35,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.testcontainers.containers.GenericContainer;
+import org.testcontainers.containers.output.Slf4jLogConsumer;
 import org.testcontainers.containers.wait.strategy.Wait;
 import org.testcontainers.images.PullPolicy;
 import org.testcontainers.images.builder.ImageFromDockerfile;
@@ -88,8 +89,8 @@ private static Stream<Arguments> runH2Spec() {
         try (var cont = new GenericContainer<>(
                 new ImageFromDockerfile().withDockerfile(Path.of("./Dockerfile")))
                 .withAccessToHost(true)
+                .withLogConsumer(new Slf4jLogConsumer(LoggerFactory.getLogger("h2spec")))
                 .withImagePullPolicy(PullPolicy.ageBased(Duration.ofDays(365)))
-                .withLogConsumer(outputFrame -> LOGGER.info(outputFrame.getUtf8StringWithoutLineEnding()))
                 .waitingFor(Wait.forLogMessage(".*Finished in.*", 1))) {
 
             org.testcontainers.Testcontainers.exposeHostPorts(port);