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POSlow PDF render with PyQt from MySQL query
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2012-09-04T09:34:54.070
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<p>Until yesterday, I was using SQLite for my application. Today I found a reason strong enough (multiple instances of application) to switch to MySQL using <code>pymysql</code>.</p> <p>At one point, my application queries the database for 300 rows:</p> <pre><code>cur.execute('select ime,brPredmeta,statusStr,sudskiBr ,sudija ,datumRasprave,statusPredmeta, zaduzen,datumZaduzenja from predmeti') sviaktivni = cur.fetchall() sviaktivni = list(sviaktivni) #make a list of tuples sviaktivni.sort(key=operator.itemgetter(0)) #sort the list </code></pre> <p>After that, I extract the variables and then use those variables to make a HTML document, which is then sent to printer (PDF or regular printer). Code for generating HTML is pretty simple; table with few rows for "header" (omitted here for clarity), then another table for "body" with code like this:</p> <pre><code>#extract the variables for tuple in sviaktivni: ime,brPredmeta,statusStr,sudskiBr ,sudija ,datumRasprave,statusPredmeta, zaduzen,datumZaduzenja = tuple #done extracting body = ('<html><head><title></title>' '<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>' '<style></style>' '</head>' '<body>' '<table align ="center" border="0" width="100%" style="table-layout:fixed">' '<tr height="10%">' '<td align="left" width="20">'+str(brojac)+'.</td>' '<td align="left" width="180">'+ime+'</td>' '<td align="left" width="100">'+str(brPredmeta)+'</td>' '<td align="left" width="80">'+statusStr+'</td>' '<td align="left" width="80">'+str(sudskiBr)+'</td>' '<td align="left" width="140">'+sudija+'</td>' '<td align="left" width="150">'+zaduzen+'</td>' '<td align="left">'+datumZaduzenja+'</td>' '<td align="right"> '+statusPredmeta+' </td>' '</tr>' '</table>' '</body>' '</html>') self.ui.printHTML.append(body) </code></pre> <p>My problem is that the query is executed instantly, but after that CPU is stuck at 100%, and the whole program just freezes. Print preview dialog is sometimes shown with data, sometimes it's just an empty window. Either way, whole app is frozen.</p> <p>There were no problems with the same code using SQLite. What should I do? Get back to sqlite and risk database corruption?</p>
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<python><mysql><sql><pyqt>
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Slow PDF render with PyQt from MySQL query
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