<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0cm;
margin-right:0cm;
margin-bottom:0cm;
margin-left:36.0pt;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
span.EmailStyle18
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:70.85pt 70.85pt 70.85pt 70.85pt;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:1937211102;
mso-list-type:hybrid;
mso-list-template-ids:-1207252832 269221911 269221913 269221915 269221903 269221913 269221915 269221903 269221913 269221915;}
@list l0:level1
{mso-level-number-format:alpha-lower;
mso-level-text:"%1\)";
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level2
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level3
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level4
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level5
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level6
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level7
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level8
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level9
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
ol
{margin-bottom:0cm;}
ul
{margin-bottom:0cm;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="FR-CH" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Hi there,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I noticed that the 3.9.0 amalgamation now contains FTS5. So it’s time to think about the evolution of FTS support in DBD::Sqlite.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">At the moment, FTS5 is still experimental, but at some point it will stabilize and become mainstream.<o:p></o:p></p>
<p class="MsoNormal">FTS5 contains incompatible changes from FTS3/4 (see <a href="http://www.sqlite.org/fts5.html#appendix_a">
http://www.sqlite.org/fts5.html#appendix_a</a>).<o:p></o:p></p>
<p class="MsoNormal">Some of those incompatibilities can be handled in the DBD::Sqlite driver and therefore will be invisible to users ; but some other points change the SQL API to FTS and therefore *<b>will</b>* be visible.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So what should be the future evolution of DBD::Sqlite with respect to FTS ? Here are some options :<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">a)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Stick with FTS4 forever to preserve backwards compatibility, and fork a new distrib DBD::SQLite::FTS5 (but then how to keep both distribs in sync ?)<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">b)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Target for a backwards-incompatible move to FTS5 at some point in the future, and advertise it long in advance<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">c)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Support 2 variants, with an option in Makefile.PL to choose the FTS version at compilation time (but this could be a nightmare for automatic toolchains).<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">d)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Try to simultaneously activate FTS3 and FTS5 in the same compilation (I don’t know if this is possible), and let users choose through runtime options.
<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">e)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Any other idea ?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">DBD::Sqlite never encountered this issue before, because the first FTS support was for FTS3, and then when sqlite.org introduced FTS4 it was fully compatible with FTS3. The only somewhat similar situation was in2010 when the FTS syntax
changed from « Standard Query Syntax » to « Extended Query Syntax » ; at that time I published the DBD::Sqlite::FTS3Transitional module to help with the migration, but this time it will not be that simple.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So what do you think ? My personal preference would be for option b). It’s not very nice to break backwards compatibility, but sometimes it must happen. Besides, I never saw any public discussions, comments or bug reports about FTS support
in DBD ::Sqlite, so the user community is probably quite small, and therefore the impact of such a change would be limited. Of course this should only be activated when FTS5 has becomes stable, which should still take a couple of months.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Once the policy issue is settled, I’m interested to volunteer for working on the technical aspects – but I have very little free time to do so, so I will not progress very fast. If anybody else has more time, they are welcome to take the
job.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Cheers, Laurent Dami<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</body>
</html>