415106 - Upgrade to sqlite 3.5.5

Status: RESOLVED WONTFIX

(Core :: SQLite and Embedded Database Bindings, defect)

Description

[Shawn Wilsher :sdwilsh]

From the release e-mail:

The big change from version 3.5.4 is that the internal virtual
machine was reworked to use operands in registers rather than
pulling operands from a stack.  The virtual machine stack has
now been removed.  The removal of the VM stack will help prevent
future stack overflow bugs and will also facilitate new optimizations
in future releases.

There should be no user-visible changes to the operation of SQLite
in this release, except that the output of EXPLAIN looks different.

In order to make this change, about 8.5% of the core SQLite code
had to be reworked.  We thought this might introduce instability.
But we have done two weeks of intensive testing, during which time
we have increased the statement test coverage to 99% and during
which we have found and fixed lots of minor bugs (mostly things
like leaking memory following a malloc failure).  But for all of
that testing, we have not detected a single bug in the new
register-based VM.  And for that reason, we believe the new
VM, and hence version 3.5.5, is stable and ready for production
use.

====
So, the question is, do we want this for b4?

Comment 1

[Mike Schroepfer]

So I don't see any clear statement of benefit here besides keeping up with the latest version.  If there were a bugfix, perf improvement, etc. I'd be more excited 

Comment 2

[Myk Melez [:myk] [@mykmelez]]

Given how much code has changed and that this is a minor version update to the stable branch, future security and stability fixes seem unlikely to be backported to the old codebase, so we'll be taking this sooner or later to get some security or perf optimization (such as those hinted at in the description of the update).

So one benefit of taking it now is that we can test it in the beta cycle rather than on a stable release.

Comment 3

[Peter Weilbacher]

Don't upgrade to 3.5.5 (yet), I heard from drh that there will be a 3.5.6 very soon (early next week). That I will also put in a few new fixes for OS/2 and _then_ I would like to get that. :-)

Comment 5

[Mike Schroepfer]

Given comment 5 not going to block on this.

Comment 6

[Shawn Wilsher :sdwilsh]

I'm actually going to WONTFIX this per comment 4, and we'll open a new one when 3.5.6 comes out.