1833473 - Fix the use of PRAGMA incremental_vacuum

Status: NEW

(Core :: Storage: IndexedDB, task, P3)

Description

[Jan Varga [:janv]]

We currently execute PRAGMA incremental_vacuum as a simple statement (ignoring any results) which leads to freeing just one page at a time. The pragma needs to be executed as a statement returning rows. See https://stackoverflow.com/questions/53746807/sqlite-incremental-vacuum-removing-only-one-free-page

So https://searchfox.org/mozilla-central/rev/11a4d97a7b5cdfa133f4bda4525649f651703018/dom/indexedDB/ActorsParent.cpp#7063 should be replaced with a loop which calls ExecuteStep until there are no results.

We can probably get rid of the split into 10% chunks, see https://searchfox.org/mozilla-central/rev/11a4d97a7b5cdfa133f4bda4525649f651703018/dom/indexedDB/ActorsParent.cpp#7009 because ExecuteStep frees one page at a time anyway and we can check for pending events in the new loop which will provide better reaction when the connection suddenly becomes active.

I also suspect that we free just one page at https://searchfox.org/mozilla-central/rev/11a4d97a7b5cdfa133f4bda4525649f651703018/dom/indexedDB/ActorsParent.cpp#13770
It seems that pragma needs to be executed using a loop and ExecuteStep as well.

Comment 1

[Jan Varga [:janv]]

It seems that Cache API might have the same problem:
https://searchfox.org/mozilla-central/rev/11a4d97a7b5cdfa133f4bda4525649f651703018/dom/cache/DBSchema.cpp#2285