StatSchema support DropIndex

src/main/java/com/alibaba/druid/sql/visitor/SchemaStatVisitor.java

@@ -51,6 +51,7 @@ import com.alibaba.druid.sql.ast.statement.SQLCommentStatement;
 import com.alibaba.druid.sql.ast.statement.SQLCreateTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLCreateViewStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDeleteStatement;
+import com.alibaba.druid.sql.ast.statement.SQLDropIndexStatement;
 import com.alibaba.druid.sql.ast.statement.SQLDropTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
 import com.alibaba.druid.sql.ast.statement.SQLInsertStatement;
@@ -1156,4 +1157,23 @@ public class SchemaStatVisitor extends SQLASTVisitorAdapter {
     public boolean visit(SQLAlterTableDropConstraint x) {
         return false;
     }
+    
+    @Override
+    public boolean visit(SQLDropIndexStatement x) {
+        setMode(x, Mode.DropIndex);
+        SQLName name = (SQLName) x.getTableName().getExpr();
+
+        String ident = name.toString();
+        setCurrentTable(ident);
+        
+        TableStat stat = getTableStat(ident);
+        stat.incrementDropIndexCount();
+
+        Map<String, String> aliasMap = getAliasMap();
+        if (aliasMap != null) {
+            aliasMap.put(ident, ident);
+        }
+        
+        return false;
+    }
 }

src/main/java/com/alibaba/druid/stat/TableStat.java

@@ -33,6 +33,15 @@ public class TableStat {
     int createCount      = 0;
     int alterCount       = 0;
     int createIndexCount = 0;
+    int dropIndexCount   = 0;
+
+    public int getDropIndexCount() {
+        return dropIndexCount;
+    }
+
+    public void incrementDropIndexCount() {
+        this.dropIndexCount++;
+    }
 
     public int getCreateIndexCount() {
         return createIndexCount;
@@ -155,6 +164,9 @@ public class TableStat {
         if (createIndexCount > 0) {
             buf.append("CreateIndex");
         }
+        if (dropIndexCount > 0) {
+            buf.append("DropIndex");
+        }
 
         return buf.toString();
     }
@@ -497,7 +509,7 @@ public class TableStat {
         Merge(16), //
         Truncate(32), //
         Alter(64), //
-        Drop(128);
+        Drop(128), DropIndex(256); //
 
         public final int mark;