The document describes the structure and format of blocks in a key-value store. It outlines the header, data, leaf index, meta, and trailer blocks. The header includes metadata like the block type and sizes. Data blocks contain compressed and uncompressed key-value entries. Leaf index blocks point to data blocks and include offsets. Meta blocks store metadata indexes. The trailer contains version and load-on-open metadata.

1. Header
Header Block Type (8B)
Entry
Compressed Size (Int)
Entry
Uncompressed Size (Int)
Entry
Offset of previous same
type block (Long)
Header
Data Block
Compressed data KeyLen (Int) ValueLen (Int) Key (Byte[]) Value (Byte[])
(Byte[])
Data Block
“Scanned
Leaf index not root format
block” section
block/Bloom
block
Header Block offset (Long)
… Offset (Int)
# of entries (Int) On disk size ( Int)
Offset (Int)
Meta Block Entry offsets (Int[]) Offset (Int) Key (Byte[])
Entry Total Size of Entries
... (Int)
Non-scanned Etnry
block section Meta Block
Entry
Intermediate
Level Data Index
Blocks (optional)
Root Data Index Header Block offset (Long)
Key length (VInt)
Entry On disk size (Int)
Fields for Key bytes (Byte[])
Load-on-open midkey Key
...
section Meta Index
Entry Root format
File Info
Bloom Filter Header
Header
metadata
Size of entries (Int)
Trailer fields Header Bloom filter version (Int)
Trailer Last key (Byte[])
Version File info offset (Long) Total byte size of bloom
filter chunks (Long) Average key length (Int)
loadOnOpenOffSet (Long)
Average value length
Offset of Middle # of hash functions (Int) (Int)
# of data index entries (Int)
leaf index block Comparator
(Long) uncompressedDataIndexSiz
Type of hash functions (Int)
e (Long)
User defined
On-disk size (Int) # of meta index entries (Int) Total key count (Long)
Index of the mid- Total uncompressed bytes
key (Int) (Long) Maximum total number of
keys (Long)
This midkey fields is part of Root numEntries (Long)
Data Index Block, appended to tail # of chunks (Int)
of Data Index Blocks. Compression codec (Int)
# of levels in the data block Comparator class
(Int)
First data block offset
(Long) Chunk index
First data block offset
(Long)
Version (Int)
Ant.Rao@gmail.com