Trait SkipWatermarkState

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pub trait SkipWatermarkState: Send {
    // Required methods
    fn has_watermark(&self) -> bool;
    fn should_delete(
        &mut self,
        key: &FullKey<&[u8]>,
        value: HummockValue<&[u8]>,
    ) -> bool;
    fn reset_watermark(&mut self);
    fn advance_watermark(
        &mut self,
        key: &FullKey<&[u8]>,
        value: HummockValue<&[u8]>,
    ) -> bool;
}

Expand description

This trait is used to maintain the state of whether the watermark has been skipped.

Required Methods§

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fn has_watermark(&self) -> bool

Returns whether there are any unused watermarks in the state.

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fn should_delete( &mut self, key: &FullKey<&[u8]>, value: HummockValue<&[u8]>, ) -> bool

Returns whether the incoming key needs to be deleted after watermark filtering. Note: Each table_id has multiple watermarks, and state defaults to forward traversal of vnodes, so you must use forward traversal of the incoming key for it to be filtered correctly.

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fn reset_watermark(&mut self)

Resets the watermark state.

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fn advance_watermark( &mut self, key: &FullKey<&[u8]>, value: HummockValue<&[u8]>, ) -> bool

Determines if the current watermark is exhausted by the passed-in key, advances to the next watermark, and returns whether the key needs to be deleted.