Struct txn_types::WriteRef

pub struct WriteRef<'a> {
    pub write_type: WriteType,
    pub start_ts: TimeStamp,
    pub short_value: Option<&'a [u8]>,
    pub has_overlapped_rollback: bool,
    pub gc_fence: Option<TimeStamp>,
}

Fields

write_type: WriteType

start_ts: TimeStamp

short_value: Option<&'a [u8]>

has_overlapped_rollback: bool

The commit_ts of transactions can be non-globally-unique. But since we store Rollback records in the same CF where Commit records is, and Rollback records are saved with user_key{start_ts} as the internal key, the collision between Commit and Rollback records can’t be avoided. In this case, we keep the Commit record, and set the has_overlapped_rollback flag to indicate that there’s also a Rollback record. Also note that has_overlapped_rollback field is only necessary when the Rollback record should be protected.

gc_fence: Option<TimeStamp>

Records the next version after this version when overlapping rollback happens on an already existed commit record.

See Write::gc_fence for more detail.

Implementations

impl WriteRef<'_>

pub fn parse(b: &[u8]) -> Result<WriteRef<'_>>

pub fn to_bytes(&self) -> Vec<u8>

fn pre_allocate_size(&self) -> usize

pub fn check_gc_fence_as_latest_version(&self, read_ts: TimeStamp) -> bool

Prev Conditions:

• The Write record self is referring to is the latest version found by reading at read_ts
• The read_ts is safe, which means, it’s not earlier than the current GC safepoint. Return: Whether the Write record is valid, ie. there’s no GC fence or GC fence doesn’t points to any other version.

pub fn is_protected(&self) -> bool

pub fn to_owned(&self) -> Write

Trait Implementations

impl<'a> Clone for WriteRef<'a>

fn clone(&self) -> WriteRef<'a>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'a> PartialEq<WriteRef<'a>> for WriteRef<'a>

fn eq(&self, other: &WriteRef<'a>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &WriteRef<'a>) -> bool

This method tests for !=.

impl<'a> StructuralPartialEq for WriteRef<'a>