Re: [PATCH v2 7/8] pack-bitmap: implement combined filter
flat view
From: Jeff King <hidden>
Date: 2021-04-06 17:54:34
On Mon, Mar 15, 2021 at 02:14:59PM +0100, Patrick Steinhardt wrote:
When the user has multiple objects filters specified, then this is internally represented by having a "combined" filter. These combined filters aren't yet supported by bitmap indices and can thus not be accelerated. Fix this by implementing support for these combined filters. The implementation is quite trivial: when there's a combined filter, we simply recurse into `filter_bitmap()` for all of the sub-filters.
The goal makes sense. Before this patch, I think your test:
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+test_expect_success 'combine filter' ' + git rev-list --objects --filter=blob:limit=1000 --filter=object:type=blob tag >expect && + git rev-list --use-bitmap-index \ + --objects --filter=blob:limit=1000 --filter=object:type=blob tag >actual && + test_bitmap_traversal expect actual +'
would pass anyway, because we'd just skip using bitmaps. Is there a way we can tell that the bitmap code actually kicked in? Maybe a perf test would make it clear (those aren't always run, but hopefully we'd eventually notice a regression there).
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+static int filter_supported(struct list_objects_filter_options *filter) +{ + int i; + + switch (filter->choice) { + case LOFC_BLOB_NONE: + case LOFC_BLOB_LIMIT: + case LOFC_OBJECT_TYPE: + return 1; + case LOFC_TREE_DEPTH: + if (filter->tree_exclude_depth == 0) + return 1; + return 0; + case LOFC_COMBINE: + for (i = 0; i < filter->sub_nr; i++) + if (!filter_supported(&filter->sub[i])) + return 0; + return 1; + default: + return 0; + } +}
Hmm. This is essentially reproducing the list in filter_bitmap() of what's OK for bitmaps. So when adding a new filter, it would have to be added in both places. Can we preserve that property of the original code? I'd think that just adding LOFC_COMBINE to filter_bitmap() would be sufficient. I.e., this hunk:
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+ if (filter->choice == LOFC_COMBINE) { + int i; + for (i = 0; i < filter->sub_nr; i++) { + filter_bitmap(bitmap_git, tip_objects, to_filter, + &filter->sub[i]); + } + return 0; + }
...except that we need to see if filter_bitmap() returns "-1" for any of the recursive calls. Which we probably should be doing anyway to propagate any errors (though I think the only "errors" we'd return are "not supported", at least for now). -Peff