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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I did some tests with OGR executing queries on a layer with
ExecuteSQL() and found that there is a memory leak occurring when you re-run
that query many times. I am calling ReleaseResultSet() between each
iteration, and I’m deleting the features objects after I use them.
I also ran a test that only does the query and doesn’t ask for any
features and there was still a leak. My test consisted of 100 concurrent
users (synchronized) over 10000 iterations. Watching the private bytes of
my process shows a slow but steady growth of memory allocation with no
de-allocation. When I comment out the call to ExecuteSQL() the problem
goes away. I also tried to use the GetLayer() function to retrieve the
table followed by calls to SetAttributeFilter() and the result was less leakage
but it still has a leak. Has anyone else ran into this problem? I’m
running the test on Windows XP and the data source is an ESRI shape file with a
few hundred records.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The code is like this:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>m_pLayer = m_pDataSource->ExecuteSQL(m_sStatement.c_str(),
NULL, "");<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=blue
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:blue'>if</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'> (m_pLayer == NULL) <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'> <font color=blue><span
style='color:blue'>throw</span></font> CPLGetLastErrorMsg();<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>m_pDataSource->ReleaseResultSet(m_pLayer);<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>m_pLayer = NULL;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>// also leaks, but not as much<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>m_pLayer = m_pDataSource->GetLayer(0);<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=blue
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:blue'>if</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'> (m_pLayer == NULL) <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'> <font color=blue><span
style='color:blue'>throw</span></font> CPLGetLastErrorMsg();<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>OGRErr err = m_pLayer->SetAttributeFilter(m_sStatement.c_str());<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>if</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'>
(err != OGRERR_NONE) <font color=blue><span style='color:blue'>throw</span></font>
CPLGetLastErrorMsg(); <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>err = m_pLayer->SetAttributeFilter(NULL);<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>if</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'>
(err != OGRERR_NONE) <font color=blue><span style='color:blue'>throw</span></font>
CPLGetLastErrorMsg(); <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>Can someone else do a test to confirm that there is
truly a leak? … Frank? … anyone? … Ferris Bueller?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>Thanks,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>Martin<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
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