692659 - IndexedDB: fix sort order for indexes

Status: RESOLVED FIXED

(Core :: Storage: IndexedDB, defect)

Description

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Consider the following data. The keypath for the objectStore is "id", and the keyPath for the index is "name".

{ id: 1, name: "a" }
{ id: 2, name: "b" }
{ id: 3, name: "b" }
{ id: 4, name: "b" }
{ id: 5, name: "d" }
{ id: 6, name: "c" }

When creating a cursor on the index, you should get the following results for the following directions of the cursor:

NEXT:
key: "a", primaryKey "1"
key: "b", primaryKey "2"
key: "b", primaryKey "3"
key: "b", primaryKey "4"
key: "c", primaryKey "6"
key: "d", primaryKey "5"

NEXT_NO_DUPLICATE:
key: "a", primaryKey "1"
key: "b", primaryKey "2"
key: "c", primaryKey "6"
key: "d", primaryKey "5"

PREV:
key: "d", primaryKey "5"
key: "c", primaryKey "6"
key: "b", primaryKey "4"
key: "b", primaryKey "3"
key: "b", primaryKey "2"
key: "a", primaryKey "1"

PREV_NO_DUPLICATE:
key: "d", primaryKey "5"
key: "c", primaryKey "6"
key: "b", primaryKey "2"
key: "a", primaryKey "1"


I think currently we get the PREV order wrong. But the PREV_NO_DUPLICATE query seems to execute in a very suboptimal way that doesn't use indexes properly.


I *think* I have ideas for how to write SQL queries that produce this result, feel free to ping me.

Comment 1

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Attachment: Patch to fix

Comment 2

[Ben Turner (not reading bugmail, use the needinfo flag!)]

Comment on attachment 572748 [details] [diff] [review]
Patch to fix

Review of attachment 572748 [details] [diff] [review]:
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Looks great!

Comment 3

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Checked in https://hg.mozilla.org/mozilla-central/rev/504d3127b9a6

Thanks again for such a quick review!