I believe the best option is d) to support both FTS4 and FTS5 at the same time,
as if they were different data types. Failing that, I like b) the best. I also
think a) is the worst option; this is not something worth forking over. --
Darren Duncan
On 2015-10-25 11:46 PM, Dami Laurent (PJ) wrote:
Hi there,
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.
At the moment, FTS5 is still experimental, but at some point it will stabilize
and become mainstream.
FTS5 contains incompatible changes from FTS3/4 (see
http://www.sqlite.org/fts5.html#appendix_a).
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 **will** be visible.
So what should be the future evolution of DBD::Sqlite with respect to FTS ? Here
are some options :
a)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 ?)
b)Target for a backwards-incompatible move to FTS5 at some point in the future,
and advertise it long in advance
c)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).
d)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.
e)Any other idea ?
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.
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.
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.
Cheers, Laurent Dami
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