Hi Garren,
I am querying a CouchDB 2.0 backend, using pouchdb-find in
pure "remote" mode, without any synchronization.
Thanks for the blog post, that helps :) . So, effectively, the
"_id": {"$gt":0} selector is by no means a way to use an index
(that's the impression I got when I was suggested to try it).
It's only a way to suppress pouchdb-find's warning, by telling it
"I know this won't fit a map/reduce, I'll be running in-memory
operations on allDocs, and I'm aware of the perf. consequences".
Correct?
Final clarification: querying with or without the _id selector
produces the exact same operations with the same perf and the only
difference is the warning when we weren't explicit enough, right?
Thanks for the work on pouchdb-find! Good day.
On 2017-01-21 08:12, Garren Smith wrote:
Hi Ronan,
When using pouchdb-find are you querying a CouchDB backend or using
PouchDB?
The reason that adding "_id": {"$gt": 0} works is because
pouchdb-find/mango fetches all the docs using the _all_docs index
and then processes the $in operator in memory.
We have added functionality that the $in operator should work without
needing the "_id": {"$gt": 0} selector. So if it didn't work that
means there is a bug in pouchdb-find. I have written a blogpost on
how pouchdb-find/mango actually works and it might help you
understand what is actually happening [1].
Cheers
Garren
[1]
http://www.redcometlabs.com/blog/2015/12/1/a-look-under-the-covers-of-pouchdb-find
On Fri, Jan 20, 2017 at 11:21 PM, Ronan Jouchet wrote:
Hi, this is a mailing-list repost of StackOverflow question
"pouchdb-find: can $in / $or queries use indexes?" [1]
I noticed that queries using $in, such as:
"type": {"$in": ["a", "b"]}
... fail to use the existing relevant index (pouchdb-find warns
"no matching index found, create an index to optimize query time").
StackOverflow user markwatsonatx suggested adding to my query
"_id": {"$gt": 0}
... and indeed I no longer get index warnings with it.
Is this expected behavior? Can anyone explain what's going on?
Thanks!
[1] http://stackoverflow.com/questions/40686383/pouchdb-find-
can-in-or-queries-use-indexes
