When I compare the database bytes before and after the 2nd
process VACUUM these bytes differ:
zero-based value value
byte offset before after my guess of what it is
2nd VAC 2nd VAC
----------- ------- ------- ----------------------
27 2 5 File change counter?
43 2 5 Schema cookie?
47 4 1 meta[1], file format?
Doesn't byte offset 47 correspond to meta[1], the file format
of the schema layer?
--- Joe Wilson <[EMAIL PROTECTED]> wrote:
> Regarding http://www.sqlite.org/cvstrac/tktview?tn=2804 ...
>
> I'm confused by the explanation.
> Ignoring the PRAGMA for the moment, I was surprised that DESC
> indexes were not available after a reconnect and VACUUM, as shown
> in the example:
>
> $ rm -f foo.db
> $ ./sqlite3-3.5.3.bin foo.db
> SQLite version 3.5.3
> Enter ".help" for instructions
> sqlite> PRAGMA legacy_file_format=OFF;
> sqlite> CREATE TABLE abc(a,b,c);
> sqlite> CREATE INDEX abc_i on abc(b desc, c asc, a desc);
> sqlite> explain query plan select * from abc order by b desc, c asc, a desc;
> 0|0|TABLE abc WITH INDEX abc_i ORDER BY
> sqlite> vacuum;
> sqlite> explain query plan select * from abc order by b desc, c asc, a desc;
> 0|0|TABLE abc WITH INDEX abc_i ORDER BY
> sqlite> .q
>
> $ ./sqlite3-3.5.3.bin foo.db
> SQLite version 3.5.3
> Enter ".help" for instructions
> sqlite> explain query plan select * from abc order by b desc, c asc, a desc;
> 0|0|TABLE abc WITH INDEX abc_i ORDER BY
> sqlite> vacuum;
> sqlite> explain query plan select * from abc order by b desc, c asc, a desc;
> 0|0|TABLE abc
>
> Notice that the DESC index is no longer available after the second
> process' VACUUM was run.
>
> If this isn't the file format being changed, then why isn't the DESC
> index being used?
>
> Is this by design?
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