On 09/15/2014 03:18 PM, Dominique Devienne wrote:
On Fri, Sep 12, 2014 at 11:48 PM, Eric Rubin-Smith <eas....@gmail.com>
wrote:
Looking at the sqlite web site and mailing lists shows that the SQLite team
has taken a stab at answering the question, "is it faster to read a blob
out of sqlite or out of a file?". See the links below.
Does the team have analogous guidance regarding write speeds?
Depends if you care only about the initial write, or also about incremental
writes.
SQLite is transactional, but does not have a level of indirection between
the row data, and the blob data. i.e. the blob is "in row". So whenever you
want to update a single byte of a blob, you must rewrite the whole row,
i.e. the whole blob(s) in that row (and I think this applies to any column
of the row, not only blob columns). This is just prohibitive, and
unmanageable in practice.
I think the only exception to this is if you use the incremental-blob API:
http://www.sqlite.org/c3ref/blob_open.html
Dan.
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