Bug 128444 – IDB: storage/indexeddb/mozilla/index-prev-no-duplicate.html fails

• Status: RESOLVED
• Resolution: FIXED
• Component: WebKit2

[Brady Eidson]

IDB: storage/indexeddb/mozilla/index-prev-no-duplicate.html fails

- The index cursor statements weren't doing secondary ordering by value.
- Something else I haven't identified yet.

[Radar WebKit Bug Importer]

<rdar://problem/16018914>

[Brady Eidson]

Have that first part fixed already.  Will fix the second part in the A.M.

[Radar WebKit Bug Importer]

<rdar://problem/16018918>

[Brady Eidson]

(In reply to comment #0)
> IDB: storage/indexeddb/mozilla/index-prev-no-duplicate.html fails
...
> - Something else I haven't identified yet.

So say you're walking an index cursor and you get to a lump of 4 record in a row that have the same key.

Those four values are sorted by their referenced value.

In the test case, we see these records in the object store:
        { key: "237-23-7736", value: { name: "Joe", height: 65, weight: 150 } },
        { key: "237-23-7737", value: { name: "Pat", height: 65, weight: 100 } },
        { key: "237-23-7738", value: { name: "Leo", height: 65, weight: 180 } },
        { key: "237-23-7739", value: { name: "Jef", height: 65, weight: 120 } },

The 'height' index has the entries:
        { key: 65, value:  "237-23-7736" },
        { key: 65, value:  "237-23-7737" },
        { key: 65, value:  "237-23-7738" },
        { key: 65, value:  "237-23-7739" },

So when walking the index backwards, you're supposed to first see the record or 7739, then 7738, then 7737, then 7736.

But when walking the index backwards *uniquely*, you're only supposed to see one of the 65 entries.  Which one?

Well, since you get to the 7739 record first (when walking backwards...) I thought it was the 7739 record.
But it turns out when picking which record to return for a unique cursor, you walk to the last record that matches - in this case, the 7736 record.

Yikes.

A new flavor of index cursor statement will fix this.

[Brady Eidson]

Created attachment 223595 [details]
Patch v1

Comment on attachment 223595 [details]
Patch v1

View in context: https://bugs.webkit.org/attachment.cgi?id=223595&action=review

> Source/WebKit2/DatabaseProcess/IndexedDB/sqlite/SQLiteIDBCursor.cpp:75
>          indexStatements.reserveCapacity(8);

Seems like we need to bump this 8 up? Isn’t there a more efficient reserveInitialCapacity?

[Brady Eidson]

http://trac.webkit.org/changeset/163741