On Friday, 28 April, 2017 15:55, Simon Slavin wrote:
> > The only difference is the explicit JOIN statement. I was under the
> > impression that using this, vs. the way I wrote it, is a matter of taste
> > that doesn’t affect the execution of the query.
> SQLite computes
> -Original Message-
> From: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org]
> On Behalf Of Simon Slavin
> Sent: Friday, 28 April, 2017 15:00
> To: SQLite mailing list
> Subject: Re: [sqlite] Query plan gone haywire lays waste to my library's
> performance
>
On 4/28/2017 4:37 PM, Jens Alfke wrote:
CREATE TABLE docs (doc_id INTEGER PRIMARY KEY, docid TEXT UNIQUE NOT NULL,
expiry_timestamp INTEGER);
CREATE INDEX docs_docid ON docs(docid);
For the record, this index is redundant. There's already an
automatically created index on docs(docid), thanks
On 28 Apr 2017, at 10:23pm, Jens Alfke wrote:
> On Apr 28, 2017, at 2:00 PM, Simon Slavin wrote:
>
>> What indexes do you have on these two tables ? I can’t recommend one
>> without knowing which columns belong to which tables.
>
> I showed them at
> On Apr 28, 2017, at 2:00 PM, Simon Slavin wrote:
>
> What indexes do you have on these two tables ? I can’t recommend one without
> knowing which columns belong to which tables.
I showed them at the end of my first message.
> First query rewritten for clarity:
> […]
On 28 Apr 2017, at 9:49pm, Jens Alfke wrote:
> SELECT revs.doc_id, sequence, docid, revid, json, deleted FROM revs, docs
> WHERE sequence>? AND current!=0 AND deleted=0 AND revs.doc_id = docs.doc_id
> ORDER BY revs.doc_id, deleted, revid DESC
> 0 0 0 SCAN TABLE revs USING
Sorry for the quick follow-up, but I’ve just run a quick test that does an
EXPLAIN QUERY PLAN for every statement that gets compiled, in an empty
database, and confirmed that the query plan comes out wrong right from the
start:
SELECT revs.doc_id, sequence, docid, revid, json, deleted FROM
I’ve got an urgent-to-me issue wherein a customer says that our library has
slowed down by several orders of magnitude in iOS 10.3 compared to iOS 9. I ran
a test case they provided and found that some queries that should be fast are
taking a very long time (~500ms) and generating huge numbers
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