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</o:shapelayout></xml><![endif]--></head><body lang=DE-CH link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Ivan,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Yes I know. </span><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>But before you introduced this property in VServer.INI I called DB.Flush() after each INSERT/DELETE/UPDATE and reading BLOBs and Pictures from files.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Mit freundlichen Grüssen<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Fabian Kneubühl<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><img width=119 height=26 id="Bild_x0020_1" src="cid:image001.png@01CD1EFB.D68FDF30" alt="Beschreibung: YSDLOGO"><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#181884'>YSD Büro für angewandte Informatik AG<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://www.ysd.ch/"><span style='color:blue'>http://www.ysd.ch</span></a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F'>Waldheimstrasse 48<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F'>CH-3012 Bern<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F'>Telefon: 031 302 18 72<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F'>Fax: 031 301 73 28<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F'>Unsere allgemeinen Geschäftsbedingungen finden Sie unter: <a href="http://www.ysd.ch/agb.pdf"><span style='color:blue'>http://www.ysd.ch/agb.pdf</span></a></span><span style='font-size:9.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=DE style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>Von:</span></b><span lang=DE style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> valentina-beta-bounces@lists.macserve.net [mailto:valentina-beta-bounces@lists.macserve.net] <b>Im Auftrag von </b>Ivan Smahin<br><b>Gesendet:</b> Freitag, 20. April 2012 13:10<br><b>An:</b> Valentina Beta<br><b>Betreff:</b> Re: Journaling<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Apr 20, 2012, at 10:23 AM, Fabian Kneubuehl wrote:<o:p></o:p></p></div><p class=MsoNormal><br><br><o:p></o:p></p><div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Ruslan,</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> </span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>I used transaction control for concurrent DB changes in other DBs. E.g. If I generate an invoice I start a TA, then I print the invoice. In the case the printing fails, I rollback all TAs else I commit. So I guarantee, that the invoices data are consistent. But flushing the DB was done by the DB itself and not by my app!</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> </span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal><br><br><o:p></o:p></p><div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>The only secure strategy to prevent a huge data loss is to flush all DB changes. Why does VServer not flush e.g. all x minutes (settable with a property in VServer.INI) </span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>vServer has FlushEachDataChanges setting in the ini.<o:p></o:p></p><div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>; 1 - Flush after any data modification.<o:p></o:p></p></div><div><p class=MsoNormal>; 0 - Default value - no flushing.<o:p></o:p></p></div><div><p class=MsoNormal>FlushEachDataChanges=0<o:p></o:p></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><p class=MsoNormal><br><br><o:p></o:p></p><div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>and what happens if cache is full?</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> </span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>It is usual state of the cache. Assume that cache is full and we ask to load one more db-page from the storage.<o:p></o:p></p></div><div><p class=MsoNormal>Firstly, we are trying to "unload" any (oldest) "unchanged" page (probably not a single page but some set of pages to improve performance) from the cache (obviously, such a page is not writing to the disk because it is not changed).<o:p></o:p></p></div><div><p class=MsoNormal>If there are no "unchanged" pages in the cache then we have to "free" some "dirty" page and such a page goes to the rollback journal first, and after that, we write it down to the db storage. If some crash happens we know how to restore the database to get rid of such a "dirty" changes.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>-- <br>Best regards,<br>Ivan Smahin<br>Senior Software Engineer<br>Paradigma Software, Inc<br>Valentina - The Ultra-Fast Database<br><a href="http://www.valentina-db.com/">http://www.valentina-db.com</a><o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p></div></div></div></body></html>