Hall of Fame

1. jkr621,554
2. Infinity08428,105
3. evilrix386,063
4. itsmeandn...345,939
5. mrjoltcola136,370
6. pgnatyuk80,095
7. Zoppo69,160
8. alb6660,430
9. AndyAins...48,452
10. trinitrotolu...48,102
11. DanRollins45,961
12. Let_Me_Be43,756
13. ozo40,128
14. Gideon737,720
15. jaime_oliv...36,480
16. pepr30,816
17. ikework23,327
18. sunnycoder20,168
19. masheik18,698
20. LordOfPo...18,490
21. JohnGaby18,296
22. johnnash...17,769
23. josgood17,000
24. abel16,556
25. Gurudenis16,260

1. jkr7,897,645
2. itsmeandn...2,356,347
3. Infinity081,955,516
4. Axter1,467,234
5. evilrix1,041,001
6. nietod859,677
7. AlexFM732,762
8. DanRollins729,138
9. jaime_oliv...725,383
10. rstaveley524,876
11. grg99392,524
12. efn329,300
13. chensu313,112
14. AlexViroc...263,393
15. Zoppo255,353
16. Salte247,544
17. ikework219,121
18. wayside215,557
19. jhance207,462
20. rajeev_d...207,388
21. ambience183,231
22. AndyAins...183,072
23. sunnycoder180,898
24. bcladd171,128
25. SteH170,387

	[x] Posted via EE Mobile
	Search, ask, and monitor your questions on the go with EE Mobile. Visit Experts Exchange from your mobile device and never be out of touch again.

Question

	[x] Attachment Details

[x]

The Solution Rating System

With so many solutions, how can you tell which solutions are most likely to help you and which ones are not? To provide you with a tool to use, we rate our solutions based on various elements that most accurately determine if a solution is a quality solution. To explain what factors affect the solution rating, here are the elements we take into consideration when formulating our solution rating.

The Grade of the Solution
The Zone Rank of the Expert Providing the Solution
The Number of Author and Expert Comments
The Number of Experts Contributing
The Feedback of the Community

Your Input Matters
Because of the way the system is set up, the most important variable in this equation is you. As a member of Experts Exchange, you are able to cast your vote on the quality of the solutions in regard to how complete, accurate, helpful and easy to understand each solution is. When you provide your feedback, each rating is adjusted accordingly. So, if you see a solution that has a poor rating that you think is a good solution, let us know by rating it. As you do, the rating will be adjusted and will become more accurate for other members of our site.

If you have any suggestions that you would like to make for our rating system, please ask a question in the Suggestions Zone of Community Support.

Thank you!

6.8

ADO Memory Leak

Asked by celestian in C++ Programming Language, Microsoft Visual C++

Tags: memory, leak, ado

VC++ 6.0 SP5, MDAC 2.8, W2K Pro SP3
I am developing an NT service that uploads data to a database. It will run 24/7. Because of this, memory leaks are of particular concern to me. I wrote a simple application that executes a select from a database continuously until you press a key. After starting the exe, I took a look at the task manager and saw the "mem usage" grow at a linear rate. There doesn't appear to be an upper bound to this growth.

01 #include <stdio.h>
02 #include <conio.h>
03 #import "c:\program files\common files\system\ado\msado15.dll" rename("EOF","adoEOF")
04
05 struct InitOle {
06 InitOle() { ::CoInitialize(NULL); }
07 ~InitOle() { ::CoUninitialize(); }
08 } _init_InitOle_;
09
10 void hitdb();
11
12 int main(int argc, char* argv[])
13 {
14      bool done = false;
17      printf("\npress any key to cancel the test...");
18      do
19      {
20            if(kbhit()) done = true;
21            hitdb();
22      } while (!done);
23      getch();
24      return 0;
25 }
26
27 void hitdb()
28 {
29      try
30      {
31            ADODB::_RecordsetPtr Rs1 = NULL;
32            Rs1.CreateInstance( __uuidof( ADODB::Recordset ) );
33            Rs1->Open( L"SELECT count(*) FROM counts",
34                  L"DSN=linestatus",
35                  ADODB::adOpenForwardOnly,
36                  ADODB::adLockReadOnly, -1 );
37            Rs1->Close();
38            Rs1 = NULL;
39      }
40      catch (_com_error &e) { printf("%s\n",e.ErrorMessage()); }
41      catch (...) { printf("Unspecified Error\n"); }
42 }

If I comment out lines 33 - 37 then there is no memory leak, leading me to believe the problem lies with ADO. Adding Rs1.Release(); to line 37.5 doesn't help. Explicitly creating a connection object doesn't help either, in fact, the leak occurs if I only open a connection to the db and nothing else. Additionally, I have tried to use a DSNless connection to avoid ODBC, but without luck. It seems that the memory used *should* return to a constant level after each call to hitdb(), but this doesn't appear to be the case.

View the Solution FREE for 30 Days

20091118-EE-VQP-93

ADO Memory Leak

Asked by celestian in C++ Programming Language, Microsoft Visual C++

Tags: memory, leak, ado

About this solution