docs: add more TRACE calls for easier debugging

src/connection.cpp

@@ -154,6 +154,8 @@ static bool ApplyPreconnAttrs(HDBC hdbc, SQLINTEGER ikey, PyObject *value, char
         return false;
     }
 
+    TRACE("ApplyPreconnAttrs.SQLSetConnectAttrW key=%d value=%p vallen=%d\n", ikey, ivalue);
+
     Py_BEGIN_ALLOW_THREADS
     ret = SQLSetConnectAttrW(hdbc, ikey, ivalue, vallen);
     Py_END_ALLOW_THREADS
@@ -186,7 +188,7 @@ PyObject* Connection_New(PyObject* pConnectString, bool fAutoCommit, long timeou
         return RaiseErrorFromHandle(0, "SQLAllocHandle", SQL_NULL_HANDLE, SQL_NULL_HANDLE);
 
     //
-    // Attributes that must be set before connecting.
+    // Attributes that must be set before connecting. These are passed via `attr_before` in python.
     //
 
     if (attrs_before)
@@ -363,6 +365,8 @@ static PyObject* Connection_set_attr(PyObject* self, PyObject* args)
 
     Connection* cnxn = (Connection*)self;
 
+    TRACE("SQLSetConnectAttr id=%d value=%d\n", id, value);
+
     SQLRETURN ret;
     Py_BEGIN_ALLOW_THREADS
     ret = SQLSetConnectAttr(cnxn->hdbc, id, (SQLPOINTER)(intptr_t)value, SQL_IS_INTEGER);

src/cursor.cpp

@@ -325,7 +325,7 @@ static bool free_results(Cursor* self, int flags)
     // this even when a query has not been executed.
 
     // If we ran out of memory, it is possible that we have a cursor but colinfos is zero.  However, we should be
-    // deleting this object, so the cursor will be freed when the HSTMT is destroyed. */
+    // deleting this object, so the cursor will be freed when the HSTMT is destroyed.
 
     assert((flags & STATEMENT_MASK) != 0);
     assert((flags & PREPARED_MASK) != 0);
@@ -344,6 +344,8 @@ static bool free_results(Cursor* self, int flags)
 
     if (StatementIsValid(self))
     {
+        TRACE("free_results: %p\n", self);
+
         if ((flags & STATEMENT_MASK) == FREE_STATEMENT)
         {
             Py_BEGIN_ALLOW_THREADS
@@ -387,6 +389,8 @@ static bool free_results(Cursor* self, int flags)
 
     self->rowcount = -1;
 
+    TRACE("free_results: done\n");
+
     return true;
 }
 
@@ -407,6 +411,8 @@ static void closeimpl(Cursor* cur)
         HSTMT hstmt = cur->hstmt;
         cur->hstmt = SQL_NULL_HANDLE;
 
+        TRACE("SQLFreeHandle\n");
+
         SQLRETURN ret;
         Py_BEGIN_ALLOW_THREADS
         ret = SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
@@ -415,6 +421,8 @@ static void closeimpl(Cursor* cur)
         // If there is already an exception, don't overwrite it.
         if (!SQL_SUCCEEDED(ret) && !PyErr_Occurred())
             RaiseErrorFromHandle(cur->cnxn, "SQLFreeHandle", cur->cnxn->hdbc, SQL_NULL_HANDLE);
+    } else {
+        TRACE("Invalid statement handle, skipping SQLFreeHandle\n");
     }
 
     Py_XDECREF(cur->pPreparedSQL);
@@ -750,12 +758,16 @@ static PyObject* execute(Cursor* cur, PyObject* pSql, PyObject* params, bool ski
         const char* pch = PyBytes_AS_STRING(query.Get());
         SQLINTEGER  cch = (SQLINTEGER)(PyBytes_GET_SIZE(query.Get()) / (isWide ? sizeof(uint16_t) : 1));
 
+        TRACE("cursor.execute: isWide=%d query_len=%d\n", isWide, cch);
+
         Py_BEGIN_ALLOW_THREADS
         if (isWide)
             ret = SQLExecDirectW(cur->hstmt, (SQLWCHAR*)pch, cch);
         else
             ret = SQLExecDirect(cur->hstmt, (SQLCHAR*)pch, cch);
         Py_END_ALLOW_THREADS
+
+        TRACE("cursor.execute, finished\n");
     }
 
     if (cur->cnxn->hdbc == SQL_NULL_HANDLE)
@@ -1136,7 +1148,7 @@ static PyObject* Cursor_setinputsizes(PyObject* self, PyObject* sizes)
         PyErr_SetString(ProgrammingError, "Invalid cursor object.");
         return 0;
     }
-    
+
     Cursor *cur = (Cursor*)self;
     if (Py_None == sizes)
     {
@@ -2526,6 +2538,8 @@ Cursor_New(Connection* cnxn)
 
         if (cnxn->timeout)
         {
+            TRACE("cursor.new: setting timeout to %d\n", cnxn->timeout);
+
             Py_BEGIN_ALLOW_THREADS
             ret = SQLSetStmtAttr(cur->hstmt, SQL_ATTR_QUERY_TIMEOUT, (SQLPOINTER)(uintptr_t)cnxn->timeout, 0);
             Py_END_ALLOW_THREADS
@@ -2538,7 +2552,7 @@ Cursor_New(Connection* cnxn)
             }
         }
 
-        TRACE("cursor.new cnxn=%p hdbc=%d cursor=%p hstmt=%d\n", (Connection*)cur->cnxn, ((Connection*)cur->cnxn)->hdbc, cur, cur->hstmt);
+        TRACE("cursor.new: cnxn=%p hdbc=%d cursor=%p hstmt=%d\n", (Connection*)cur->cnxn, ((Connection*)cur->cnxn)->hdbc, cur, cur->hstmt);
     }
 
     return cur;

src/params.cpp

@@ -1310,6 +1310,8 @@ void FreeParameterData(Cursor* cur)
 {
     // Unbinds the parameters and frees the parameter buffer.
 
+    TRACE("FreeParameterData");
+
     if (cur->paramInfos)
     {
         // MS ODBC will crash if we use an HSTMT after the HDBC has been freed.
@@ -1330,6 +1332,8 @@ void FreeParameterInfo(Cursor* cur)
     // Internal function to free just the cached parameter information.  This is not used by the general cursor code
     // since this information is also freed in the less granular free_results function that clears everything.
 
+    TRACE("FreeParameterInfo");
+
     Py_XDECREF(cur->pPreparedSQL);
     PyMem_Free(cur->paramtypes);
     cur->pPreparedSQL = 0;