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maplefu pushed a commit to branch mwish-bitmap-update
in repository https://gitbox.apache.org/repos/asf/kvrocks-website.git

commit 892472996fd260e399c1b43667ff2d9e18d1ea46
Author: mwish <[email protected]>
AuthorDate: Mon Jul 22 22:34:32 2024 +0800

    Add document for bitmap with empty segment and smaller than 1KiB segment
---
 community/data-structure-on-rocksdb.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/community/data-structure-on-rocksdb.md 
b/community/data-structure-on-rocksdb.md
index 7e0eaf3..f7347c0 100644
--- a/community/data-structure-on-rocksdb.md
+++ b/community/data-structure-on-rocksdb.md
@@ -212,6 +212,8 @@ key|version|index => |    fragment   |
 
 When the user requests to get it of position P, Kvrocks would first fetch the 
metadata with bitmap's key and calculate the index of the fragment with bit 
position, then fetch the bitmap fragment with composed key and find the bit in 
fragment offset. For example, `getbit bitmap 8193`, the fragment index is `1` 
(8193/8192) and subkey is `bitmap|1|1024` (when the version is 1, and fragment 
index is `1`, kvrocks will use `1 * 1024` as the index key), then fetch the 
subkey from RocksDB and ch [...]
 
+An non exists segment means all bits are 0 in this segment. The bitmap design 
is very efficient when the bitmap is sparse. Besides, an segment could be less 
than 1KiB, and the "padding" bits are always regarded as 0.
+
 ## SortedInt
 
 SortedInt is a set with members being type int and sorted in ascending order:

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