Make buffer size configurable via properties file

README.md

@@ -112,6 +112,7 @@ In addition to the standard connection parameters the driver supports a number o
 | binaryTransfer                | Boolean |          true           | Use binary format for sending and receiving data if possible. Setting this to false disables any binary transfer                                                                                                                                                                                                                              |
 | binaryTransferEnable          | String |           ""            | Comma separated list of types to enable binary transfer. Either OID numbers or names                                                                                                                                                                                                                                                          |
 | binaryTransferDisable         | String |           ""            | Comma separated list of types to disable binary transfer. Either OID numbers or names. Overrides values in the driver default set and values set with binaryTransferEnable.                                                                                                                                                                   |
+| binaryTransferBlobBufferSize  | Integer |          4096           | Size of buffers for copying inputs to outputs in case of OID creation using Blobs. Since 42.7.1.                                                                                                                                                                                                                                              |
 | prepareThreshold              | Integer |            5            | Statement prepare threshold. A value of -1 stands for forceBinary                                                                                                                                                                                                                                                                             |
 | preparedStatementCacheQueries | Integer |           256           | Specifies the maximum number of entries in per-connection cache of prepared statements. A value of 0 disables the cache.                                                                                                                                                                                                                      |
 | preparedStatementCacheSizeMiB | Integer |            5            | Specifies the maximum size (in megabytes) of a per-connection prepared statement cache. A value of 0 disables the cache.                                                                                                                                                                                                                      |

docs/content/documentation/use.md

@@ -199,6 +199,9 @@ A comma separated list of types to enable binary transfer. Either OID numbers or
 A comma separated list of types to disable binary transfer. Either OID numbers or names.
 Over-rides values in the driver default set and values set with binaryTransferEnable.
 
+* **`binaryTransferBlobBufferSize (`*int*`)`** *Default `4096`*\
+Size of buffers for copying inputs to outputs in case of OID creation using Blobs. Since 42.7.1.
+
 * **`databaseMetadataCacheFields (`*int*`)`** *Default `65536`*\
 Specifies the maximum number of fields to be cached per connection.
 A value of 0 disables the cache.

pgjdbc/src/main/java/org/postgresql/PGProperty.java

@@ -116,6 +116,15 @@ public enum PGProperty {
       "true",
       "Use binary format for sending and receiving data if possible"),
 
+  /**
+   * Size of buffers for copying inputs to outputs in case of OID creation using Blobs.
+   * @since   42.7.1
+   */
+  BINARY_TRANSFER_BLOB_BUFFER_SIZE(
+      "binaryTransferBlobBufferSize",
+      "4096",
+      "Size of buffers for copying inputs to outputs in case of OID creation using Blobs"),
+
   /**
    * Comma separated list of types to disable binary transfer. Either OID numbers or names.
    * Overrides values in the driver default set and values set with binaryTransferEnable.

pgjdbc/src/main/java/org/postgresql/ds/common/BaseDataSource.java

@@ -1731,6 +1731,14 @@ public void setXmlFactoryFactory(@Nullable String xmlFactoryFactory) {
     PGProperty.XML_FACTORY_FACTORY.set(properties, xmlFactoryFactory);
   }
 
+  public int getBinaryTransferBlobBufferSize() {
+    return PGProperty.BINARY_TRANSFER_BLOB_BUFFER_SIZE.getIntNoCheck(properties);
+  }
+
+  public void setBinaryTransferBlobBufferSize(int binaryTransferBlobBufferSize) {
+    PGProperty.BINARY_TRANSFER_BLOB_BUFFER_SIZE.set(properties, binaryTransferBlobBufferSize);
+  }
+
   /*
    * Alias methods below, these are to help with ease-of-use with other database tools / frameworks
    * which expect normal java bean getters / setters to exist for the property names.

pgjdbc/src/main/java/org/postgresql/jdbc/PgConnection.java

@@ -179,6 +179,11 @@ private enum ReadOnlyBehavior {
    */
   private final Set<? extends Integer> binaryDisabledOids;
 
+  /**
+   * Buffer size for transfering binary data
+   */
+  private final int binaryTransferBlobBufferSize;
+
   private int rsHoldability = ResultSet.CLOSE_CURSORS_AT_COMMIT;
   private int savepointId = 0;
   // Connection's autocommit state.
@@ -286,6 +291,19 @@ public PgConnection(HostSpec[] hostSpecs,
       binaryOids.removeAll(binaryDisabledOids);
     }
 
+    int userBinaryTransferBlobBufferSize = PGProperty.BINARY_TRANSFER_BLOB_BUFFER_SIZE.getInt(info);
+    if (userBinaryTransferBlobBufferSize > 0) {
+      this.binaryTransferBlobBufferSize = userBinaryTransferBlobBufferSize;
+    } else {
+      String binaryTransferBlobBufferSizeDefaultValue = castNonNull(
+          PGProperty.BINARY_TRANSFER_BLOB_BUFFER_SIZE.getDefaultValue());
+      LOGGER.log(Level.WARNING, "Unsupported value for binaryTransferBlobBufferSize: {0}, will use "
+          + "default value {1}", new Object[]{userBinaryTransferBlobBufferSize,
+            binaryTransferBlobBufferSizeDefaultValue});
+      this.binaryTransferBlobBufferSize =
+          Integer.parseInt(binaryTransferBlobBufferSizeDefaultValue);
+    }
+
     // split for receive and send for better control
     Set<Integer> useBinarySendForOids = new HashSet<>(binaryOids);
 
@@ -1246,6 +1264,10 @@ public void setForceBinary(boolean newValue) {
     LOGGER.log(Level.FINE, "  setForceBinary = {0}", newValue);
   }
 
+  public int getBinaryTransferBlobBufferSize() {
+    return binaryTransferBlobBufferSize;
+  }
+
   public void setTypeMapImpl(Map<String, Class<?>> map) throws SQLException {
     typemap = map;
   }

pgjdbc/src/main/java/org/postgresql/jdbc/PgPreparedStatement.java

@@ -83,6 +83,8 @@ class PgPreparedStatement extends PgStatement implements PreparedStatement {
 
   private @Nullable TimeZone defaultTimeZone;
 
+  private final int binaryTransferBlobBufferSize;
+
   PgPreparedStatement(PgConnection connection, String sql, int rsType, int rsConcurrency,
       int rsHoldability) throws SQLException {
     this(connection, connection.borrowQuery(sql), rsType, rsConcurrency, rsHoldability);
@@ -108,6 +110,7 @@ class PgPreparedStatement extends PgStatement implements PreparedStatement {
     // TODO: this.wantsGeneratedKeysAlways = true;
 
     setPoolable(true); // As per JDBC spec: prepared and callable statements are poolable by
+    this.binaryTransferBlobBufferSize = Math.max(64 * 1024, connection.getBinaryTransferBlobBufferSize());
   }
 
   final int maximumNumberOfParameters() {
@@ -1199,7 +1202,7 @@ protected long createBlob(int i, InputStream inputStream,
     long oid = lom.createLO();
     LargeObject lob = lom.open(oid);
     OutputStream outputStream = lob.getOutputStream();
-    byte[] buf = new byte[4096];
+    byte[] buf = new byte[(int) Math.min(length, binaryTransferBlobBufferSize)];
     try {
       long remaining;
       if (length > 0) {