On 2018/06/13 12:21 AM, skywind mailing lists wrote:
Hi,
the original database is malformed. So, I cannot access it anymore besides
doing a dump.
There is currently no known way to read this since Inf and -Inf are not
recognized as floats but in stead look like identifiers. Perhaps this is
a useful enhancement to SQLite - but either way, right now your best bet
is indeed to search-replace the entire text file.
As to your other question about why it is malformed - it simply means
that the schema doesn't match the data structure/layout/constraints
anymore and sqlite can't fix it and can't even know what all is wrong.
Asking why specifically is not useful.
It's like when you see two random people on the street and ask "Are they
brother and sister?". If the answer is "No", there is no more that can
be said. It is not useful to ask "which one is not the brother?" or "why
are they not brother and sister?".
It's a silly analogy, but it's hard to think of a better one now - The
schema and data are simply not happy together. In most cases this would
be because a Unique key (perhaps Primary) got written halfway when disk
access died and now has a situation where it has duplicate values in the
Key. It might however also be a root page index that falls outside the
file, or indeed a myriad of possible things - or worse - a combination
of things so that if it reported "Index has duplicates" and you manage
to fix that (assuming you know some magic), then you will find the next
index is broken, and then page isn't where it should be, and... and...
and... - so there really is no point in in saying what is wrong, just to
know that the DB is broken to the point where SQLite knows it is broken,
but doesn't know if any of it is still o.k. or what all is specifically
broken.
The corruptions may be vast and wide, but the reason is always singular
- There was a media write that failed to complete. That's all that needs
to be known, and to help prevent these things from happening, there is
only one good solution: choose more safe Journal modes. And yes, it may
come at a speed penalty. (On phones specifically you can also avoid DB
updates when battery is low, but that is not a fool-proof solution. A
user can yank out a battery, etc.)
I hope this helps to make sense of it somewhat, but I know none of it
really provides a solution, so apologies for that.
cheers,
Ryan
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