Struct BTree 

pub struct BTree { /* private fields */ }

B-tree key-value store

Implementations

impl BTree

pub fn new(buffer_pool: Arc<BufferPool>) -> Result<Self>

Create a new B-tree with an empty root page

pub fn open(root_page: PageId, buffer_pool: Arc<BufferPool>) -> Self

Open an existing B-tree

pub fn root_page(&self) -> PageId

Get root page ID

pub fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>>

Get a value by key

pub fn insert(&mut self, key: &[u8], value: &[u8]) -> Result<Option<Vec<u8>>>

Insert a key-value pair Returns the old value if the key already existed

pub fn delete(&mut self, key: &[u8]) -> Result<Option<Vec<u8>>>

Delete a key Returns the old value if the key existed

pub fn range<'a>( &'a self, start: &[u8], end: &[u8], ) -> Result<RangeIterator<'a>>

Create a range iterator

pub fn iter(&self) -> Result<RangeIterator<'_>>

Iterate over all entries

pub fn for_each_value<F>(&self, f: F) -> Result<()>

where F: FnMut(&[u8]) -> Result<bool>,

Iterate all values in the B-tree, calling f with borrowed value bytes. For inline cells, the value slice points directly into page memory (zero-copy). For overflow cells, value bytes are assembled and passed as owned. Return Ok(false) from the callback to stop iteration early.

pub fn count_leaf_items(&self) -> Result<u64>

Count all non-deleted leaf entries without reading cell data. This only inspects slot flags — O(pages) with minimal per-slot work.