Performance improvements

Summary:
Changed to convert from UTF8 to UTF16 only once instead of two times.
Changed to clean internal buffers lazily instead of cleaning them each time.
**Design doc/spec**:
**Docs impact**: none
**Preliminary Reviewer(s)**:
**Final Reviewer**:

Test Plan: https://app.circleci.com/pipelines/github/memsql/singlestore-odbc-connector/2777

Reviewers: pmishchenko-ua

Reviewed By: pmishchenko-ua

Subscribers: engineering-list

JIRA Issues: PLAT-6356

Differential Revision: https://grizzly.internal.memcompute.com/D59687

.circleci/config.yml

@@ -21,7 +21,7 @@ version: 2.1
 parameters:
   driver-version:
     type: string
-    default: "1.1.0"
+    default: "1.1.1"
 
 commands:
   setup-environment-linux:

CMakeLists.txt

@@ -24,10 +24,10 @@ SET(CMAKE_OSX_DEPLOYMENT_TARGET "10.9" CACHE STRING "Minimum OS X deployment ver
 
 SET(MARIADB_ODBC_VERSION_MAJOR 1)
 SET(MARIADB_ODBC_VERSION_MINOR 1)
-SET(MARIADB_ODBC_VERSION_PATCH 0)
+SET(MARIADB_ODBC_VERSION_PATCH 1)
 SET(MARIADB_ODBC_VERSION_QUALITY "ga")
 
-SET(MARIADB_ODBC_VERSION "01.01.0000")
+SET(MARIADB_ODBC_VERSION "01.01.0001")
 
 IF(UNICODE OR NOT ANSI)
   MESSAGE(STATUS "Configuring to build Unicode driver")

ma_odbc.h

@@ -316,6 +316,7 @@ struct st_ma_odbc_stmt
   MYSQL_BIND                *result;
   MYSQL_BIND                *params;
   int                       PutParam;
+  int                       LastSQLGetDataColumn;
   my_bool                   RebindParams;
   my_bool                   bind_done;
   long long                 AffectedRows;

ma_platform_win32.c

@@ -177,7 +177,6 @@ int MADB_ConvertAnsi2Unicode(Client_Charset *cc, const char *AnsiString, SQLLEN
 {
   SQLLEN    RequiredLength;
   SQLWCHAR *Tmp= UnicodeString;
-  int       rc= 0;
 
   if (LengthIndicator)
     *LengthIndicator= 0;
@@ -195,39 +194,63 @@ int MADB_ConvertAnsi2Unicode(Client_Charset *cc, const char *AnsiString, SQLLEN
   if (AnsiLength == SQL_NTS || AnsiLength == -1)
     IsNull= 1;
 
-  /* calculate required length */
-  RequiredLength= MultiByteToWideChar(cc->CodePage, 0, AnsiString, IsNull ? -1 : (int)AnsiLength, NULL, 0);
-
-  /* Set LengthIndicator */
-  if (LengthIndicator)
-    *LengthIndicator= RequiredLength - IsNull;
   if (!UnicodeLength)
+  {
+    // Return buffer is empty
+    // Get WideChar length if needed and return
+    if (LengthIndicator) {
+      RequiredLength= MultiByteToWideChar(cc->CodePage, 0, AnsiString, IsNull ? -1 : (int)AnsiLength, NULL, 0);
+      if (RequiredLength < 1)
+      {
+        if (Error)
+          MADB_SetError(Error, MADB_ERR_HY000, "Ansi to Unicode conversion error occurred", GetLastError());
+        return 1;
+      }
+
+      // Set LengthIndicator
+      *LengthIndicator= RequiredLength - IsNull;
+    }
     return 0;
+  }
+
+  RequiredLength= MultiByteToWideChar(cc->CodePage, 0, AnsiString, IsNull ? -1 : (int)AnsiLength, Tmp, (int)UnicodeLength);
+  if (RequiredLength < 1 && GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
+    // Buffer is too small
+
+    RequiredLength= MultiByteToWideChar(cc->CodePage, 0, AnsiString, IsNull ? -1 : (int)AnsiLength, NULL, 0);
+
+    // Set LengthIndicator
+    if (LengthIndicator)
+      *LengthIndicator= RequiredLength - IsNull;
 
-  if (RequiredLength > UnicodeLength)
     Tmp= (SQLWCHAR *)malloc(RequiredLength * sizeof(SQLWCHAR));
-
-  RequiredLength= MultiByteToWideChar(cc->CodePage, 0, AnsiString, IsNull ? -1 : (int)AnsiLength, Tmp, (int)RequiredLength);
-  if (RequiredLength < 1)
-  {
-    if (Error)
-      MADB_SetError(Error, MADB_ERR_HY000, "Ansi to Unicode conversion error occurred", GetLastError());
-    rc= 1;
-    goto end;
-  }
 
-  /* Truncation */
-  if (Tmp != UnicodeString)
-  {
+    RequiredLength= MultiByteToWideChar(cc->CodePage, 0, AnsiString, IsNull ? -1 : (int)AnsiLength, Tmp, (int)RequiredLength);
+    if (RequiredLength < 1)
+    {
+      if (Error)
+        MADB_SetError(Error, MADB_ERR_HY000, "Ansi to Unicode conversion error occurred", GetLastError());
+      free(Tmp);
+      return 1;
+    }
+
     wcsncpy(UnicodeString, L"", 1);
     wcsncat(UnicodeString, Tmp, UnicodeLength- 1);
+    free(Tmp);
     if (Error)
       MADB_SetError(Error, MADB_ERR_01004, NULL, 0);
+  } else if (RequiredLength < 1)
+  {
+    // Conversion error occurred
+    if (Error)
+      MADB_SetError(Error, MADB_ERR_HY000, "Ansi to Unicode conversion error occurred", GetLastError());
+    return 1;
+  } else {
+    // Successfully converted string
+    // Set LengthIndicator
+    if (LengthIndicator)
+      *LengthIndicator= RequiredLength - IsNull;
   }
-end:
-  if (Tmp != UnicodeString)
-    free(Tmp);
-  return rc;
 }
 
 /* Returns required length for result string with(if dest and dest length are provided)

odbc_3_api.c

@@ -825,7 +825,6 @@ SQLRETURN SQL_API SQLGetData(SQLHSTMT StatementHandle,
     SQLLEN *StrLen_or_IndPtr)
 {
   MADB_Stmt *Stmt= (MADB_Stmt*)StatementHandle;
-  unsigned int i;
   MADB_DescRecord *IrdRec;
 
   if (StatementHandle== SQL_NULL_HSTMT)
@@ -856,19 +855,17 @@ SQLRETURN SQL_API SQLGetData(SQLHSTMT StatementHandle,
     return MADB_SetError(&Stmt->Error, MADB_ERR_HY090, NULL, 0);
   }
 
-  /* reset offsets for other columns. Doing that here since "internal" calls should not do that */
-  for (i=0; i < mysql_stmt_field_count(Stmt->stmt); i++)
+  /* reset offsets for column. Doing that here since "internal" calls should not do that */
+  if (Stmt->LastSQLGetDataColumn != Col_or_Param_Num)
   {
-    if (i != Col_or_Param_Num - 1)
+    IrdRec= MADB_DescGetInternalRecord(Stmt->Ird, Col_or_Param_Num - 1, MADB_DESC_READ);
+    if (IrdRec)
     {
-      IrdRec= MADB_DescGetInternalRecord(Stmt->Ird, i, MADB_DESC_READ);
-      if (IrdRec)
-      {
-        MADB_FREE(IrdRec->InternalBuffer);
-      }
-      Stmt->CharOffset[i]= 0;
+      MADB_FREE(IrdRec->InternalBuffer);
     }
+    Stmt->CharOffset[Col_or_Param_Num - 1]= 0;
   }
+  Stmt->LastSQLGetDataColumn= Col_or_Param_Num;
 
   return Stmt->Methods->GetData(StatementHandle, Col_or_Param_Num, TargetType, TargetValuePtr, BufferLength, StrLen_or_IndPtr, FALSE);
 }