Enum JournalMode 

pub enum JournalMode {
    Wal,
    Mvcc,
}

Selects the durability + concurrency story a database operates under. Toggled by PRAGMA journal_mode = … (see crate::sql::pragma::execute_pragma).

• JournalMode::Wal (default) — every read goes through the legacy table → pager path; every write fsyncs a per-page commit frame. This is the only mode pre-Phase-11 builds knew about, and it’s what file-format-v5 + WAL-format-v2 files produce by default.
• JournalMode::Mvcc — opts the database into Phase 11’s multi-version concurrency control. Enables snapshot-isolated reads (consult MvStore first, fall back to the pager) and BEGIN CONCURRENT writes (Phase 11.4). On-disk format is unchanged; the WAL header’s clock_high_water byte range carries the persisted clock value either way.

Phase 11.3 ships the parser surface and the per-database setting; the read path doesn’t change behaviour yet. The Mvcc value is observable via the PRAGMA read form so callers can confirm the toggle landed.

Variants

Wal

Default — legacy WAL-backed pager. Every commit fsyncs a page-level frame; every read consults staged → wal_cache → on_disk.

Mvcc

Phase 11 MVCC + BEGIN CONCURRENT. Same on-disk format as Wal; the in-memory MvStore sits in front of the pager for reads, and writes go through commit-time validation.

Implementations

impl JournalMode

pub fn from_str_lossless(s: &str) -> Option<Self>

Parses a PRAGMA value (case-insensitive). Returns None for unrecognized inputs so the caller can surface a typed unknown journal_mode error with the bad string.

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

The lowercase string form the PRAGMA read renders.

Trait Implementations

impl Clone for JournalMode

fn clone(&self) -> JournalMode

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for JournalMode

impl Debug for JournalMode

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

Formats the value using the given formatter.

impl Default for JournalMode

fn default() -> JournalMode

Returns the “default value” for a type.

impl Display for JournalMode

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

Formats the value using the given formatter.

impl Eq for JournalMode

impl PartialEq for JournalMode

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for JournalMode