optimize preparedstatement cache memory usage

mysql-async/src/main/scala/com/github/mauricio/async/db/mysql/codec/LitePreparedStatementHolder.scala

@@ -0,0 +1,14 @@
+package com.github.mauricio.async.db.mysql.codec
+
+/**
+  * optimize memory usage
+  * we only need statementId,columnSize and parameterSize
+  */
+class LitePreparedStatementHolder(val statementId: Array[Byte], val columnSize: Int, val parameterSize: Int)
+
+object LitePreparedStatementHolder {
+  def apply(preparedStatementHolder: PreparedStatementHolder): LitePreparedStatementHolder = {
+    val res = new LitePreparedStatementHolder(preparedStatementHolder.statementId, preparedStatementHolder.columns.size, preparedStatementHolder.parameters.size)
+    res
+  }
+}

mysql-async/src/main/scala/com/github/mauricio/async/db/mysql/codec/MySQLConnectionHandler.scala

@@ -59,7 +59,7 @@ class MySQLConnectionHandler(
   private final val sendLongDataEncoder = new SendLongDataEncoder()
   private final val currentParameters = new ArrayBuffer[ColumnDefinitionMessage]()
   private final val currentColumns = new ArrayBuffer[ColumnDefinitionMessage]()
-  private final val parsedStatements = new HashMap[String,PreparedStatementHolder]()
+  private final val parsedStatements = new HashMap[String,LitePreparedStatementHolder]()
   private final val binaryRowDecoder = new BinaryRowDecoder()
 
   private var currentPreparedStatementHolder : PreparedStatementHolder = null
@@ -201,7 +201,7 @@ class MySQLConnectionHandler(
 
     this.parsedStatements.get(preparedStatement.statement) match {
       case Some( item ) => {
-        this.executePreparedStatement(item.statementId, item.columns.size, preparedStatement.values, item.parameters)
+        this.executePreparedStatement(item.statementId, item.columnSize, preparedStatement.values, item.parameterSize)
       }
       case None => {
         decoder.preparedStatementPrepareStarted()
@@ -237,8 +237,8 @@ class MySQLConnectionHandler(
     }
   }
 
-  private def executePreparedStatement( statementId : Array[Byte], columnsCount : Int, values : Seq[Any], parameters : Seq[ColumnDefinitionMessage] ): Future[ChannelFuture] = {
-    decoder.preparedStatementExecuteStarted(columnsCount, parameters.size)
+  private def executePreparedStatement( statementId : Array[Byte], columnsCount : Int, values : Seq[Any], parameterSize : Int ): Future[ChannelFuture] = {
+    decoder.preparedStatementExecuteStarted(columnsCount, parameterSize)
     this.currentColumns.clear()
     this.currentParameters.clear()
 
@@ -259,10 +259,10 @@ class MySQLConnectionHandler(
         }
       }
       channelFuture flatMap { _ =>
-        writeAndHandleError(new PreparedStatementExecuteMessage(statementId, values, nonLongIndices.toSet, parameters))
+        writeAndHandleError(new PreparedStatementExecuteMessage(statementId, values, nonLongIndices.toSet, parameterSize))
       }
     } else {
-      writeAndHandleError(new PreparedStatementExecuteMessage(statementId, values, nonLongIndices.toSet, parameters))
+      writeAndHandleError(new PreparedStatementExecuteMessage(statementId, values, nonLongIndices.toSet, parameterSize))
     }
   }
 
@@ -308,12 +308,12 @@ class MySQLConnectionHandler(
     this.currentQuery = new MutableResultSet[ColumnDefinitionMessage](columns)
 
     if ( this.currentPreparedStatementHolder != null ) {
-      this.parsedStatements.put( this.currentPreparedStatementHolder.statement, this.currentPreparedStatementHolder )
+      this.parsedStatements.put( this.currentPreparedStatementHolder.statement, LitePreparedStatementHolder(this.currentPreparedStatementHolder) )
       this.executePreparedStatement(
         this.currentPreparedStatementHolder.statementId,
         this.currentPreparedStatementHolder.columns.size,
         this.currentPreparedStatement.values,
-        this.currentPreparedStatementHolder.parameters
+        this.currentPreparedStatementHolder.parameters.size
       )
       this.currentPreparedStatementHolder = null
       this.currentPreparedStatement = null

mysql-async/src/main/scala/com/github/mauricio/async/db/mysql/encoder/PreparedStatementExecuteEncoder.scala

@@ -33,7 +33,7 @@ class PreparedStatementExecuteEncoder( rowEncoder : BinaryRowEncoder ) extends M
     buffer.writeByte(0x00) // no cursor
     buffer.writeInt(1)
 
-    if ( m.parameters.isEmpty ) {
+    if ( m.parameterSize == 0 ) {
       buffer
     } else {
       Unpooled.wrappedBuffer(buffer, encodeValues(m.values, m.valuesToInclude))

mysql-async/src/main/scala/com/github/mauricio/async/db/mysql/message/client/PreparedStatementExecuteMessage.scala

@@ -22,5 +22,5 @@ case class PreparedStatementExecuteMessage (
                                              statementId : Array[Byte],
                                              values : Seq[Any],
                                              valuesToInclude : Set[Int],
-                                             parameters : Seq[ColumnDefinitionMessage] )
+                                             parameterSize : Int )
   extends ClientMessage( ClientMessage.PreparedStatementExecute )