Enum ModuleOverlap 

pub enum ModuleOverlap {
    Exclusive,
    Safe,
}

Whether a module tolerates a second process of itself running alongside.

Most modules are single-writer on their store (a WAL, a capture log, a resident index behind a writer barrier), and two processes on one store corrupt it. So a swap, which overlaps the old and new process by design, is refused unless the module’s config opts in with overlap: "safe".

Variants

Exclusive

Never run two processes of this module at once. The default.

Safe

The module has said a second process of itself is harmless for the length of a swap.

Declare it only if a second instance can run for a few seconds without touching ANY single-writer store: every database, WAL, index, projector and scheduled job the module owns. A lease on part of that state is not enough. broca’s session lease guards WAL appends while its run index, its store projector and its archive fold timer (which unlinks live WAL files) stay single-writer, so broca is exclusive despite holding a lease. The refusal only fires after this has been decided, so the decision is the check.

Implementations

impl ModuleOverlap

pub fn as_str(self) -> &'static str

Trait Implementations

impl Clone for ModuleOverlap

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for ModuleOverlap

impl Debug for ModuleOverlap

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ModuleOverlap

fn default() -> Self

Returns the “default value” for a type.

impl Eq for ModuleOverlap

impl PartialEq for ModuleOverlap

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ModuleOverlap