Performance | Improved performance of column name string lookups

src/main/java/com/microsoft/sqlserver/jdbc/SQLServerCallableStatement.java

@@ -24,8 +24,9 @@
 import java.sql.Time;
 import java.sql.Timestamp;
 import java.text.MessageFormat;
-import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.HashMap;
+import java.util.TreeMap;
 import java.util.UUID;
 
 
@@ -46,7 +47,8 @@ public class SQLServerCallableStatement extends SQLServerPreparedStatement imple
     private static final long serialVersionUID = 5044984771674532350L;
 
     /** the call param names */
-    private ArrayList<String> parameterNames;
+    private HashMap<String, Integer> parameterNames;
+    private TreeMap<String, Integer> insensitiveParameterNames;
 
     /** Number of registered OUT parameters */
     int nOutParams = 0;
@@ -1282,10 +1284,13 @@ private int findColumn(String columnName) throws SQLServerException {
                 }
 
                 ResultSet rs = s.executeQueryInternal(metaQuery.toString());
-                parameterNames = new ArrayList<>();
+                parameterNames = new HashMap<>();
+                insensitiveParameterNames = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
+                int columnIndex = 0;
                 while (rs.next()) {
-                    String parameterName = rs.getString(4);
-                    parameterNames.add(parameterName.trim());
+                    String p = rs.getString(4);
+                    parameterNames.put(p, columnIndex);
+                    insensitiveParameterNames.put(p, columnIndex++);
                 }
             } catch (SQLException e) {
                 SQLServerException.makeFromDriverError(connection, this, e.toString(), null, false);
@@ -1301,47 +1306,19 @@ private int findColumn(String columnName) throws SQLServerException {
 
         // handle `@name` as well as `name`, since `@name` is what's returned
         // by DatabaseMetaData#getProcedureColumns
-        String columnNameWithoutAtSign = null;
-        if (columnName.startsWith("@")) {
-            columnNameWithoutAtSign = columnName.substring(1, columnName.length());
-        } else {
-            columnNameWithoutAtSign = columnName;
-        }
+        String columnNameWithSign = columnName.startsWith("@") ? columnName : "@" + columnName;
 
         // In order to be as accurate as possible when locating parameter name
         // indexes, as well as be deterministic when running on various client
         // locales, we search for parameter names using the following scheme:
 
         // 1. Search using case-sensitive non-locale specific (binary) compare first.
-        // 2. Search using case-insensitive, non-locale specific (binary) compare last.
-
-        int i;
-        int matchPos = -1;
-        // Search using case-sensitive, non-locale specific (binary) compare.
-        // If the user supplies a true match for the parameter name, we will find it here.
-        for (i = 0; i < l; i++) {
-            String sParam = parameterNames.get(i);
-            sParam = sParam.substring(1, sParam.length());
-            if (sParam.equals(columnNameWithoutAtSign)) {
-                matchPos = i;
-                break;
-            }
-        }
-
-        if (-1 == matchPos) {
-            // Check for case-insensitive match using a non-locale aware method.
-            // Use VM supplied String.equalsIgnoreCase to do the "case-insensitive search".
-            for (i = 0; i < l; i++) {
-                String sParam = parameterNames.get(i);
-                sParam = sParam.substring(1, sParam.length());
-                if (sParam.equalsIgnoreCase(columnNameWithoutAtSign)) {
-                    matchPos = i;
-                    break;
-                }
-            }
+        // 2. Search using case-insensitive, non-locale specific (binary) compare last.        
+        Integer matchPos = parameterNames.get(columnNameWithSign);
+        if (null == matchPos) {
+            matchPos = insensitiveParameterNames.get(columnNameWithSign);
         }
-
-        if (-1 == matchPos) {
+        if (null == matchPos) {
             MessageFormat form = new MessageFormat(
                     SQLServerException.getErrString("R_parameterNotDefinedForProcedure"));
             Object[] msgArgs = {columnName, procedureName};

src/main/java/com/microsoft/sqlserver/jdbc/SQLServerResultSet.java

@@ -24,6 +24,8 @@
 import java.sql.SQLXML;
 import java.text.MessageFormat;
 import java.util.Calendar;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.logging.Level;
@@ -153,6 +155,9 @@ final void setCurrentRowType(RowType rowType) {
     /** Flag set to true if the current row was updated through this ResultSet object */
     private boolean updatedCurrentRow = false;
 
+    // Column name hash map for caching.
+    private final Map<String, Integer> columnNames = new HashMap<>();
+
     final boolean getUpdatedCurrentRow() {
         return updatedCurrentRow;
     }
@@ -632,17 +637,22 @@ public void close() throws SQLServerException {
     /**
      * Finds a column index given a column name.
      * 
-     * @param columnName
+     * @param userProvidedColumnName
      *        the name of the column
      * @throws SQLServerException
      *         If any errors occur.
      * @return the column index
      */
     @Override
-    public int findColumn(String columnName) throws SQLServerException {
-        loggerExternal.entering(getClassNameLogging(), "findColumn", columnName);
+    public int findColumn(String userProvidedColumnName) throws SQLServerException {
+        loggerExternal.entering(getClassNameLogging(), "findColumn", userProvidedColumnName);
         checkClosed();
 
+        Integer value = columnNames.get(userProvidedColumnName);
+        if (null != value) {
+            return value;
+        }
+
         // In order to be as accurate as possible when locating column name
         // indexes, as well as be deterministic when running on various client
         // locales, we search for column names using the following scheme:
@@ -663,9 +673,9 @@ public int findColumn(String columnName) throws SQLServerException {
 
         // Search using case-sensitive, non-locale specific (binary) compare.
         // If the user supplies a true match for the column name, we will find it here.
-        int i;
-        for (i = 0; i < columns.length; i++) {
-            if (columns[i].getColumnName().equals(columnName)) {
+        for (int i = 0; i < columns.length; i++) {
+            if (columns[i].getColumnName().equals(userProvidedColumnName)) {
+                columnNames.put(userProvidedColumnName, i + 1);
                 loggerExternal.exiting(getClassNameLogging(), "findColumn", i + 1);
                 return i + 1;
             }
@@ -675,14 +685,15 @@ public int findColumn(String columnName) throws SQLServerException {
         // Per JDBC spec, 27.3 "The driver will do a case-insensitive search for
         // columnName in it's attempt to map it to the column's index".
         // Use VM supplied String.equalsIgnoreCase to do the "case-insensitive search".
-        for (i = 0; i < columns.length; i++) {
-            if (columns[i].getColumnName().equalsIgnoreCase(columnName)) {
+        for (int i = 0; i < columns.length; i++) {
+            if (columns[i].getColumnName().equalsIgnoreCase(userProvidedColumnName)) {
+                columnNames.put(userProvidedColumnName, i + 1);
                 loggerExternal.exiting(getClassNameLogging(), "findColumn", i + 1);
                 return i + 1;
             }
         }
         MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_invalidColumnName"));
-        Object[] msgArgs = {columnName};
+        Object[] msgArgs = {userProvidedColumnName};
         SQLServerException.makeFromDriverError(stmt.connection, stmt, form.format(msgArgs), "07009", false);
 
         return 0;