Struct VisibilityMap 

pub struct VisibilityMap { /* private fields */ }

Per-page visibility tracking bitmap. Pages are indexed by a dense u32 — sparse table sizes can overshoot the bitmap and trigger lazy resize via ensure_capacity.

Implementations

impl VisibilityMap

pub fn new() -> VisibilityMap

Create an empty visibility map. Initial capacity is minimal; pages get added as mark_all_visible extends the bitmap.

pub fn with_capacity(pages: u32) -> VisibilityMap

Pre-allocate room for pages pages. Useful when the caller knows the table size up-front (e.g. ANALYZE freshly imported data).

pub fn is_all_visible(&self, page: u32) -> bool

Returns true when page is marked all-visible. Page indexes beyond the current bitmap return false (treated as “unknown / not-visible”).

pub fn mark_all_visible(&self, page: u32)

Mark page as all-visible. Extends the bitmap on demand. Idempotent — calling twice has the same effect as calling once.

pub fn clear_all_visible(&self, page: u32)

Clear the all-visible bit for page. Called by every write path that touches the page (insert / update / delete). Cheap no-op when the page wasn’t marked or doesn’t exist in the bitmap yet.

pub fn all_visible_count(&self) -> u64

Number of all-visible pages currently tracked.

pub fn capacity_pages(&self) -> u64

Total number of pages the bitmap can address (capacity, not “set count”). Mostly useful for diagnostics and memory accounting.

pub fn clear(&self)

Reset the entire bitmap to “not all-visible”. Used by crash recovery and DROP TABLE.

pub fn mark_range_visible(&self, start: u32, end: u32)

Bulk-mark a contiguous range of pages [start, end) as all-visible. Used by VACUUM after a successful sweep of a page range.

pub fn snapshot(&self, limit_pages: u32) -> Vec<(u32, bool)>

Iterate over (page, all_visible_bool) for the first limit_pages pages. Diagnostic / debugging helper.

Trait Implementations

impl Default for VisibilityMap

fn default() -> VisibilityMap

Returns the “default value” for a type.