[CONJ-1145] compression of packet with sufficient length without havi…

…ng good compression, avoid using unnecessary variables
mariadb-corporation · Jan 12, 2024 · 573eb3d · 573eb3d
1 parent e955360
commit 573eb3d
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Showing 2 changed files with 16 additions and 6 deletions.
diff --git a/src/main/java/org/mariadb/jdbc/internal/io/output/CompressPacketOutputStream.java b/src/main/java/org/mariadb/jdbc/internal/io/output/CompressPacketOutputStream.java
@@ -75,7 +75,6 @@ public class CompressPacketOutputStream extends AbstractPacketOutputStream {
   private static final float MIN_COMPRESSION_RATIO = 0.9f;
   private final byte[] header = new byte[7];
   private final byte[] subHeader = new byte[4];
-  private boolean subHeaderIsGenerated = false;
   private int maxPacketLength = MAX_PACKET_LENGTH;
   private int compressSeqNo;
   private byte[] remainingData = new byte[0];
@@ -162,7 +161,7 @@ protected void flushBuffer(boolean commandEnd) throws IOException {
             subHeader[1] = (byte) (pos >>> 8);
             subHeader[2] = (byte) (pos >>> 16);
             subHeader[3] = (byte) this.seqNo++;
-            subHeaderIsGenerated = true;
+
             deflater.write(subHeader, 0, 4);
             deflater.write(buf, 0, uncompressSize - (remainingData.length + 4));
             deflater.finish();
@@ -251,6 +250,9 @@ protected void flushBuffer(boolean commandEnd) throws IOException {
             }
             pos = 0;
             return;
+          } else {
+            // reset sequence to previous value, since not sent because compression wasn't high enough
+            this.seqNo--;
           }
         }
       }
@@ -277,10 +279,8 @@ protected void flushBuffer(boolean commandEnd) throws IOException {
       subHeader[0] = (byte) pos;
       subHeader[1] = (byte) (pos >>> 8);
       subHeader[2] = (byte) (pos >>> 16);
-      // Avoid increasing the sequence of subHeader twice
-      if (!subHeaderIsGenerated){
-        subHeader[3] = (byte) this.seqNo++;
-      }
+      subHeader[3] = (byte) this.seqNo++;
+
       out.write(subHeader, 0, 4);
       out.write(buf, 0, uncompressSize - (remainingData.length + 4));
       cmdLength += remainingData.length;

diff --git a/src/test/java/org/mariadb/jdbc/ConnectionTest.java b/src/test/java/org/mariadb/jdbc/ConnectionTest.java
@@ -1092,4 +1092,14 @@ public void connectionAttributes() throws SQLException {
       }
     }
   }
+
+  @Test
+  public void compressionWhenPacketIsNotCompressedEnough() throws SQLException {
+    try (Connection connection = setConnection("&useCompression=true&log")) {
+      try (Statement s = connection.createStatement()) {
+        String sql = "-- :: userIDaebcda5cb52dc741f20fe495327ddbfc8411cc53663eec3a5ffdb1f30626d39cc606822\nselect version();";
+        s.execute(sql);
+      }
+    }
+  }
 }