Merge pull request microsoft#972 from david-puglielli/redundant-apis

Fix for redundant calls to SQLNumResultCols and SQLRowCount

Author: david-puglielli

source/pdo_sqlsrv/pdo_stmt.cpp

@@ -593,12 +593,26 @@ int pdo_sqlsrv_stmt_execute( _Inout_ pdo_stmt_t *stmt TSRMLS_DC )
         if ( execReturn == SQL_NO_DATA ) {
             stmt->column_count = 0;
             stmt->row_count = 0;
+            driver_stmt->column_count = 0;
+            driver_stmt->row_count = 0;
         }
         else {
-            stmt->column_count = core::SQLNumResultCols( driver_stmt TSRMLS_CC );
+            if (driver_stmt->column_count == ACTIVE_NUM_COLS_INVALID) {
+                stmt->column_count = core::SQLNumResultCols( driver_stmt TSRMLS_CC );
+                driver_stmt->column_count = stmt->column_count;
+            }
+            else {
+                stmt->column_count = driver_stmt->column_count;
+            }
 
-            // return the row count regardless if there are any rows or not
-            stmt->row_count = core::SQLRowCount( driver_stmt TSRMLS_CC );
+            if (driver_stmt->row_count == ACTIVE_NUM_ROWS_INVALID) {
+                // return the row count regardless if there are any rows or not
+                stmt->row_count = core::SQLRowCount( driver_stmt TSRMLS_CC );
+                driver_stmt->row_count = stmt->row_count;
+            }
+            else {
+                stmt->row_count = driver_stmt->row_count;
+            }
         }
 
         // workaround for a bug in the PDO driver manager.  It is fairly simple to crash the PDO driver manager with 
@@ -692,11 +706,16 @@ int pdo_sqlsrv_stmt_fetch( _Inout_ pdo_stmt_t *stmt, _In_ enum pdo_fetch_orienta
         SQLSMALLINT odbc_fetch_ori = pdo_fetch_ori_to_odbc_fetch_ori( ori );
         bool data = core_sqlsrv_fetch( driver_stmt, odbc_fetch_ori, offset TSRMLS_CC );
 
-        // support for the PDO rowCount method.  Since rowCount doesn't call a method, PDO relies on us to fill the 
-        // pdo_stmt_t::row_count member
-        if( driver_stmt->past_fetch_end || driver_stmt->cursor_type != SQL_CURSOR_FORWARD_ONLY ) {
+        // support for the PDO rowCount method.  Since rowCount doesn't call a
+        // method, PDO relies on us to fill the pdo_stmt_t::row_count member
+        // The if condition was changed from 
+        // `driver_stmt->past_fetch_end || driver_stmt->cursor_type != SQL_CURSOR_FORWARD_ONLY` 
+        // because it caused SQLRowCount to be called at each fetch if using a non-forward cursor
+        // which is unnecessary and a performance hit
+        if( driver_stmt->past_fetch_end || driver_stmt->cursor_type == SQL_CURSOR_DYNAMIC) {
 
             stmt->row_count = core::SQLRowCount( driver_stmt TSRMLS_CC );
+            driver_stmt->row_count = stmt->row_count;
 
             // a row_count of -1 means no rows, but we change it to 0
             if( stmt->row_count == -1 ) {
@@ -1146,6 +1165,9 @@ int pdo_sqlsrv_stmt_next_rowset( _Inout_ pdo_stmt_t *stmt TSRMLS_DC )
 
         // return the row count regardless if there are any rows or not
         stmt->row_count = core::SQLRowCount( driver_stmt TSRMLS_CC );
+        
+        driver_stmt->column_count = stmt->column_count;
+        driver_stmt->row_count = stmt->row_count;
     }
     catch( core::CoreException& ) {
 

source/shared/core_sqlsrv.h

@@ -182,6 +182,11 @@ const int SQL_MAX_ERROR_MESSAGE_LENGTH = SQL_MAX_MESSAGE_LENGTH * 2;
 // max size of a date time string when converting from a DateTime object to a string
 const int MAX_DATETIME_STRING_LEN = 256;
 
+// identifier for whether or not we have obtained the number of rows and columns
+// of a result
+const short ACTIVE_NUM_COLS_INVALID = -99;
+const long ACTIVE_NUM_ROWS_INVALID = -99;
+
 // precision and scale for the date time types between servers
 const int SQL_SERVER_2005_DEFAULT_DATETIME_PRECISION = 23;
 const int SQL_SERVER_2005_DEFAULT_DATETIME_SCALE = 3;
@@ -1438,8 +1443,9 @@ struct sqlsrv_stmt : public sqlsrv_context {
     bool has_rows;                        // Has_rows is set if there are actual rows in the row set
     bool fetch_called;                    // Used by core_sqlsrv_get_field to return an informative error if fetch not yet called 
     int last_field_index;                 // last field retrieved by core_sqlsrv_get_field
-    bool past_next_result_end;            // core_sqlsrv_next_result sets this to true when the statement goes beyond the 
-                                          // last results
+    bool past_next_result_end;            // core_sqlsrv_next_result sets this to true when the statement goes beyond the last results
+    short column_count;                   // Number of columns in the current result set obtained from SQLNumResultCols
+    long row_count;                       // Number of rows in the current result set obtained from SQLRowCount
     unsigned long query_timeout;          // maximum allowed statement execution time
     zend_long buffered_query_limit;       // maximum allowed memory for a buffered query (measured in KB)
     bool date_as_string;                  // false by default but the user can set this to true to retrieve datetime values as strings

source/shared/core_stmt.cpp

@@ -140,6 +140,8 @@ sqlsrv_stmt::sqlsrv_stmt( _In_ sqlsrv_conn* c, _In_ SQLHANDLE handle, _In_ error
     fetch_called( false ),
     last_field_index( -1 ),
     past_next_result_end( false ),
+    column_count( ACTIVE_NUM_COLS_INVALID ),
+    row_count( ACTIVE_NUM_ROWS_INVALID ),
     query_timeout( QUERY_TIMEOUT_INVALID ),
     date_as_string(false),
     format_decimals(false),       // no formatting needed
@@ -225,6 +227,8 @@ void sqlsrv_stmt::new_result_set( TSRMLS_D )
     this->past_next_result_end = false;
     this->past_fetch_end = false;
     this->last_field_index = -1;
+    this->column_count = ACTIVE_NUM_COLS_INVALID;
+    this->row_count = ACTIVE_NUM_ROWS_INVALID;
 
     // delete any current results
     if( current_results ) {
@@ -819,9 +823,17 @@ bool core_sqlsrv_fetch( _Inout_ sqlsrv_stmt* stmt, _In_ SQLSMALLINT fetch_orient
         CHECK_CUSTOM_ERROR( stmt->past_fetch_end, stmt, SQLSRV_ERROR_FETCH_PAST_END ) {
             throw core::CoreException();
         }
+        
         // First time only
         if ( !stmt->fetch_called ) {
-            SQLSMALLINT has_fields = core::SQLNumResultCols( stmt TSRMLS_CC );
+            SQLSMALLINT has_fields;
+            if (stmt->column_count != ACTIVE_NUM_COLS_INVALID) {
+                has_fields = stmt->column_count;
+            } else {
+                has_fields = core::SQLNumResultCols( stmt TSRMLS_CC );
+                stmt->column_count = has_fields;
+            }
+            
             CHECK_CUSTOM_ERROR( has_fields == 0, stmt, SQLSRV_ERROR_NO_FIELDS ) {
                 throw core::CoreException();
             }
@@ -1066,10 +1078,27 @@ void core_sqlsrv_get_field( _Inout_ sqlsrv_stmt* stmt, _In_ SQLUSMALLINT field_i
 
 bool core_sqlsrv_has_any_result( _Inout_ sqlsrv_stmt* stmt TSRMLS_DC )
 {
-    // Use SQLNumResultCols to determine if we have rows or not.
-    SQLSMALLINT num_cols = core::SQLNumResultCols( stmt TSRMLS_CC );
-    // use SQLRowCount to determine if there is a rows status waiting
-    SQLLEN rows_affected = core::SQLRowCount( stmt TSRMLS_CC );
+    SQLSMALLINT num_cols;
+    SQLLEN rows_affected;
+    
+    if (stmt->column_count != ACTIVE_NUM_COLS_INVALID) {
+        num_cols = stmt->column_count;
+    }
+    else {
+        // Use SQLNumResultCols to determine if we have rows or not
+        num_cols = core::SQLNumResultCols( stmt TSRMLS_CC );
+        stmt->column_count = num_cols;
+    }
+    
+    if (stmt->row_count != ACTIVE_NUM_ROWS_INVALID) {
+        rows_affected = stmt->row_count;
+    }
+    else {
+        // Use SQLRowCount to determine if there is a rows status waiting
+        rows_affected = core::SQLRowCount( stmt TSRMLS_CC );
+        stmt->row_count = rows_affected;
+    }
+    
     return (num_cols != 0) || (rows_affected > 0);
 }
 

source/sqlsrv/stmt.cpp

@@ -1791,7 +1791,12 @@ SQLSMALLINT get_resultset_meta_data(_Inout_ sqlsrv_stmt * stmt)
 
     if (num_cols == 0) {
         getMetaData = true;
-        num_cols = core::SQLNumResultCols(stmt TSRMLS_CC);
+        if (stmt->column_count == ACTIVE_NUM_COLS_INVALID) {
+            num_cols = core::SQLNumResultCols(stmt TSRMLS_CC);
+            stmt->column_count = num_cols;
+        } else {
+            num_cols = stmt->column_count;
+        }
     }
 
     try {

source/sqlsrv/util.cpp

@@ -205,8 +205,8 @@ ss_error SS_ERRORS[] = {
     }, 
 
     {
-      SS_SQLSRV_ERROR_ZEND_OBJECT_FAILED,
-      { IMSSP, (SQLCHAR*)"Failed to create an instance of class %1!s!.", -30, true }
+        SS_SQLSRV_ERROR_ZEND_OBJECT_FAILED,
+        { IMSSP, (SQLCHAR*)"Failed to create an instance of class %1!s!.", -30, true }
     },
 
     {

test/functional/sqlsrv/sqlsrv_empty_result_error.phpt

@@ -153,7 +153,7 @@ echo "Null result set, call next result first: #############################\n";
 
 $stmt = sqlsrv_query($conn, "TestEmptySetProc @a='a', @b='c'");
 NextResult($stmt, []);
-Fetch($stmt, [$errorFuncSeq()]);
+Fetch($stmt, [$errorNoFields]);
 
 // Call next_result twice in succession on a null result set
 echo "Null result set, call next result twice: #############################\n";