improve sql parser performance

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlLexer.java

@@ -209,13 +209,24 @@ public class MySqlLexer extends Lexer {
         {
             boolean hasSpecial = false;
             int startIndex = pos + 1;
-            int endIndex = text.indexOf('\'', startIndex);
+            int endIndex = -1; //text.indexOf('\'', startIndex);
+            for (int i = startIndex; i < text.length(); ++i) {
+                final char ch = text.charAt(i);
+                if (ch == '\\') {
+                    hasSpecial = true;
+                }
+                if (ch == '\'') {
+                    endIndex = i;
+                    break;
+                }
+            }
+            
             if (endIndex == -1) {
                 throw new ParserException("unclosed str");
             }
 
             String stringVal = subString(startIndex, endIndex - startIndex);
-            hasSpecial = stringVal.indexOf('\\') != -1;
+//            hasSpecial = stringVal.indexOf('\\') != -1;
 
             if (!hasSpecial) {
                 this.stringVal = stringVal;

src/main/java/com/alibaba/druid/sql/parser/Lexer.java

@@ -79,7 +79,7 @@ public class Lexer {
         return text.charAt(index);
     }
     
-    public String addSymbol() {
+    public final String addSymbol() {
         return subString(mark, bufPos);
     }
 

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

@@ -137,9 +137,30 @@ public class SchemaStatVisitor extends SQLASTVisitorAdapter {
     }
 
     private String handleName(String ident) {
-        ident = ident.replaceAll("\"", "");
-        ident = ident.replaceAll("`", "");
-        ident = ident.replaceAll(" ", "");
+        boolean flag0 = false;
+        boolean flag1 = false;
+        boolean flag2 = false;
+        for (int i = 0; i < ident.length(); ++i) {
+            final char ch = ident.charAt(i);
+            if (ch == '\"') {
+                flag0 = true;
+            } else if (ch == '`') {
+                flag1 = true;
+            } else if (ch == ' ') {
+                flag2 = true;
+            }
+        }
+        if (flag0) {
+            ident = ident.replaceAll("\"", "");
+        }
+        
+        if (flag1) {
+            ident = ident.replaceAll("`", "");
+        }
+        
+        if (flag2) {
+            ident = ident.replaceAll(" ", "");
+        }
 
         ident = aliasWrap(ident);