Struct FileChangeCounter

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pub struct FileChangeCounter(/* private fields */);
Expand description

§File change counter (4 Bytes)

The file change counter is a 4-byte big-endian integer at offset 24 that is incremented whenever the database file is unlocked after having been modified. When two or more processes are reading the same database file, each process can detect database changes from other processes by monitoring the change counter. A process will normally want to flush its database page cache when another process modified the database, since the cache has become stale. The file change counter facilitates this.

In WAL mode, changes to the database are detected using the wal-index and so the change counter is not needed. Hence, the change counter might not be incremented on each transaction in WAL mode.

Methods from Deref<Target = u32>§

1.43.0 · Source

pub const MIN: u32 = 0u32

1.43.0 · Source

pub const MAX: u32 = 4_294_967_295u32

1.53.0 · Source

pub const BITS: u32 = 32u32

Trait Implementations§

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impl Debug for FileChangeCounter

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

Formats the value using the given formatter. Read more
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impl Default for FileChangeCounter

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fn default() -> FileChangeCounter

Returns the “default value” for a type. Read more
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impl Deref for FileChangeCounter

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type Target = u32

The resulting type after dereferencing.
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fn deref(&self) -> &Self::Target

Dereferences the value.
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impl Name for FileChangeCounter

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const NAME: &'static str = "FileChangeCounter"

Auto Trait Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<P, T> Receiver for P
where P: Deref<Target = T> + ?Sized, T: ?Sized,

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type Target = T

🔬This is a nightly-only experimental API. (arbitrary_self_types)
The target type on which the method may be called.
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.