避免创建两个AggregateFunction实例

lealone · Jun 15, 2015 · 5bee0ff · 5bee0ff
1 parent 8a37ef0
commit 5bee0ff
Show file tree

Hide file tree

Showing 5 changed files with 34 additions and 9 deletions.
diff --git a/lealone-sql/src/main/java/org/lealone/command/Parser.java b/lealone-sql/src/main/java/org/lealone/command/Parser.java
@@ -4877,12 +4877,12 @@ protected Table readTableOrView(String tableName) {
                 }
             }
         }
-        //TODO 在分布式环境下，如果先在一个JVM上执行create table，再执行insert这样的dml，
-        //或者执行create table和insert的是不同JVM，这时由于表的元数据未及时更新到执行insert的JVM，
-        //所以有可能出现此异常，因为不同JVM上的表元数据通过zookeeper异步更新，
-        //有可能执行create table的线程很快结束了，但是zookeeper还未通知，这时insert时就找不到表。
-        //对于这种情况，client重视即可解决，不过还有没有更好的办法呢?
-        //client在使用h2作为内存数据库对SQL预解析时也会碰到这样的情况。
+        // TODO 在分布式环境下，如果先在一个JVM上执行create table，再执行insert这样的dml，
+        // 或者执行create table和insert的是不同JVM，这时由于表的元数据未及时更新到执行insert的JVM，
+        // 所以有可能出现此异常，因为不同JVM上的表元数据通过zookeeper异步更新，
+        // 有可能执行create table的线程很快结束了，但是zookeeper还未通知，这时insert时就找不到表。
+        // 对于这种情况，client重视即可解决，不过还有没有更好的办法呢?
+        // client在使用h2作为内存数据库对SQL预解析时也会碰到这样的情况。
         throw DbException.get(ErrorCode.TABLE_OR_VIEW_NOT_FOUND_1, tableName);
     }
 

diff --git a/lealone-sql/src/main/java/org/lealone/command/ddl/CreateAggregate.java b/lealone-sql/src/main/java/org/lealone/command/ddl/CreateAggregate.java
@@ -30,6 +30,7 @@ public CreateAggregate(Session session) {
         super(session);
     }
 
+    @Override
     public int update() {
         session.commit(true);
         session.getUser().checkAdmin();
@@ -66,6 +67,7 @@ public void setForce(boolean force) {
         this.force = force;
     }
 
+    @Override
     public int getType() {
         return CommandInterface.CREATE_AGGREGATE;
     }

diff --git a/lealone-sql/src/main/java/org/lealone/command/ddl/DropAggregate.java b/lealone-sql/src/main/java/org/lealone/command/ddl/DropAggregate.java
@@ -26,6 +26,7 @@ public DropAggregate(Session session) {
         super(session);
     }
 
+    @Override
     public int update() {
         session.getUser().checkAdmin();
         session.commit(true);
@@ -49,6 +50,7 @@ public void setIfExists(boolean ifExists) {
         this.ifExists = ifExists;
     }
 
+    @Override
     public int getType() {
         return CommandInterface.DROP_AGGREGATE;
     }

diff --git a/lealone-sql/src/main/java/org/lealone/dbobject/UserAggregate.java b/lealone-sql/src/main/java/org/lealone/dbobject/UserAggregate.java
@@ -45,29 +45,35 @@ public AggregateFunction getInstance() {
         }
     }
 
+    @Override
     public String getCreateSQLForCopy(Table table, String quotedName) {
         throw DbException.throwInternalError();
     }
 
+    @Override
     public String getDropSQL() {
         return "DROP AGGREGATE IF EXISTS " + getSQL();
     }
 
+    @Override
     public String getCreateSQL() {
         return "CREATE FORCE AGGREGATE " + getSQL() + " FOR " + Parser.quoteIdentifier(className);
     }
 
+    @Override
     public int getType() {
         return DbObject.AGGREGATE;
     }
 
+    @Override
     public synchronized void removeChildrenAndResources(Session session) {
         database.removeMeta(session, getId());
         className = null;
         javaClass = null;
         invalidate();
     }
 
+    @Override
     public void checkRename() {
         throw DbException.getUnsupportedException("AGGREGATE");
     }

diff --git a/lealone-sql/src/main/java/org/lealone/expression/JavaAggregate.java b/lealone-sql/src/main/java/org/lealone/expression/JavaAggregate.java
@@ -36,13 +36,15 @@ public class JavaAggregate extends Expression {
     private int dataType;
     private Connection userConnection;
     private int lastGroupRowId;
+    private AggregateFunction aggregateFunction;
 
     public JavaAggregate(UserAggregate userAggregate, Expression[] args, Select select) {
         this.userAggregate = userAggregate;
         this.args = args;
         this.select = select;
     }
 
+    @Override
     public int getCost() {
         int cost = 5;
         for (Expression e : args) {
@@ -51,18 +53,22 @@ public int getCost() {
         return cost;
     }
 
+    @Override
     public long getPrecision() {
         return Integer.MAX_VALUE;
     }
 
+    @Override
     public int getDisplaySize() {
         return Integer.MAX_VALUE;
     }
 
+    @Override
     public int getScale() {
         return DataType.getDataType(dataType).defaultScale;
     }
 
+    @Override
     public String getSQL(boolean isDistributed) {
         StatementBuilder buff = new StatementBuilder();
         buff.append(Parser.quoteIdentifier(userAggregate.getName())).append('(');
@@ -73,10 +79,12 @@ public String getSQL(boolean isDistributed) {
         return buff.append(')').toString();
     }
 
+    @Override
     public int getType() {
         return dataType;
     }
 
+    @Override
     public boolean isEverything(ExpressionVisitor visitor) {
         switch (visitor.getType()) {
         case ExpressionVisitor.DETERMINISTIC:
@@ -98,12 +106,14 @@ public boolean isEverything(ExpressionVisitor visitor) {
         return true;
     }
 
+    @Override
     public void mapColumns(ColumnResolver resolver, int level) {
         for (Expression arg : args) {
             arg.mapColumns(resolver, level);
         }
     }
 
+    @Override
     public Expression optimize(Session session) {
         userConnection = session.createConnection(false);
         int len = args.length;
@@ -125,18 +135,22 @@ public Expression optimize(Session session) {
         return this;
     }
 
+    @Override
     public void setEvaluatable(TableFilter tableFilter, boolean b) {
         for (Expression e : args) {
             e.setEvaluatable(tableFilter, b);
         }
     }
 
     private AggregateFunction getInstance() throws SQLException {
-        AggregateFunction agg = userAggregate.getInstance();
-        agg.init(userConnection);
-        return agg;
+        if (aggregateFunction == null) {
+            aggregateFunction = userAggregate.getInstance();
+            aggregateFunction.init(userConnection);
+        }
+        return aggregateFunction;
     }
 
+    @Override
     public Value getValue(Session session) {
         HashMap<Expression, Object> group = select.getCurrentGroup();
         if (group == null) {
@@ -157,6 +171,7 @@ public Value getValue(Session session) {
         }
     }
 
+    @Override
     public void updateAggregate(Session session) {
         HashMap<Expression, Object> group = select.getCurrentGroup();
         if (group == null) {