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use bytes::Bytes;
/// Represents a key-value pair known not to be a tombstone.
#[non_exhaustive]
#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct KeyValue {
pub key: Bytes,
pub value: Bytes,
pub seq: u64,
pub create_ts: i64,
pub expire_ts: Option<i64>,
}
/// Represents a key-value pair that may be a tombstone.
///
/// This is the entry type passed to compaction for each key value pair.
#[derive(Debug, Clone, PartialEq)]
pub struct RowEntry {
/// The key bytes.
pub key: Bytes,
/// The value, which may be a regular value, merge operand, or tombstone.
pub value: ValueDeletable,
/// The sequence number of this entry.
pub seq: u64,
/// The creation timestamp (if set).
pub create_ts: Option<i64>,
/// The expiration timestamp (if set).
pub expire_ts: Option<i64>,
}
impl RowEntry {
pub(crate) fn new(
key: Bytes,
value: ValueDeletable,
seq: u64,
create_ts: Option<i64>,
expire_ts: Option<i64>,
) -> Self {
Self {
key,
value,
seq,
create_ts,
expire_ts,
}
}
pub(crate) fn estimated_size(&self) -> usize {
let mut size = self.key.len() + self.value.len();
// Add size for sequence number
size += std::mem::size_of::<u64>();
// Add size for timestamps
if self.create_ts.is_some() {
size += std::mem::size_of::<i64>();
}
if self.expire_ts.is_some() {
size += std::mem::size_of::<i64>();
}
size
}
/// Returns the encoded size of this entry when written to an SST block.
/// The `key_prefix_len` is the number of bytes shared with the block's first key.
pub(crate) fn encoded_size(&self, key_prefix_len: usize) -> usize {
let key_suffix_len = self.key.len() - key_prefix_len;
let mut size = std::mem::size_of::<u16>() // key_prefix_len
+ std::mem::size_of::<u16>() // key_suffix_len
+ key_suffix_len
+ std::mem::size_of::<u64>() // seq
+ std::mem::size_of::<u8>(); // flags
if self.expire_ts.is_some() {
size += std::mem::size_of::<i64>();
}
if self.create_ts.is_some() {
size += std::mem::size_of::<i64>();
}
if !self.value.is_tombstone() {
size += std::mem::size_of::<u32>(); // value_len
size += self.value.len();
}
size
}
#[cfg(test)]
pub(crate) fn new_value(key: &[u8], value: &[u8], seq: u64) -> Self {
Self {
key: Bytes::copy_from_slice(key),
value: ValueDeletable::Value(Bytes::copy_from_slice(value)),
seq,
create_ts: None,
expire_ts: None,
}
}
#[cfg(test)]
pub(crate) fn new_merge(key: &[u8], value: &[u8], seq: u64) -> Self {
Self {
key: Bytes::copy_from_slice(key),
value: ValueDeletable::Merge(Bytes::copy_from_slice(value)),
seq,
create_ts: None,
expire_ts: None,
}
}
#[cfg(test)]
pub(crate) fn new_tombstone(key: &[u8], seq: u64) -> Self {
Self {
key: Bytes::copy_from_slice(key),
value: ValueDeletable::Tombstone,
seq,
create_ts: None,
expire_ts: None,
}
}
#[cfg(test)]
pub(crate) fn with_create_ts(&self, create_ts: i64) -> Self {
Self {
key: self.key.clone(),
value: self.value.clone(),
seq: self.seq,
create_ts: Some(create_ts),
expire_ts: self.expire_ts,
}
}
#[cfg(test)]
pub(crate) fn with_expire_ts(&self, expire_ts: i64) -> Self {
Self {
key: self.key.clone(),
value: self.value.clone(),
seq: self.seq,
create_ts: self.create_ts,
expire_ts: Some(expire_ts),
}
}
}
impl From<RowEntry> for KeyValue {
fn from(entry: RowEntry) -> Self {
KeyValue {
key: entry.key,
value: entry
.value
.as_bytes()
.expect("RowEntry should have a value"),
seq: entry.seq,
create_ts: entry.create_ts.unwrap_or(0),
expire_ts: entry.expire_ts,
}
}
}
/// Represents a value for a key.
///
/// This enum distinguishes between:
/// - `Value`: A regular value entry
/// - `Merge`: A merge operand (used with merge operators)
/// - `Tombstone`: A deletion marker
///
/// Compaction filters receive this type to determine entry type and decide
/// how to handle each entry.
#[derive(Debug, Clone, PartialEq)]
pub enum ValueDeletable {
/// A regular value.
Value(Bytes),
/// A merge operand (used with merge operators).
Merge(Bytes),
/// A tombstone (deletion marker).
Tombstone,
}
#[allow(clippy::len_without_is_empty)]
impl ValueDeletable {
/// Returns the length of the value in bytes, or 0 for tombstones.
pub fn len(&self) -> usize {
match self {
ValueDeletable::Value(v) | ValueDeletable::Merge(v) => v.len(),
ValueDeletable::Tombstone => 0,
}
}
/// Returns true if this is a tombstone (deletion marker).
pub fn is_tombstone(&self) -> bool {
matches!(self, ValueDeletable::Tombstone)
}
/// Returns the value bytes if this is a Value or Merge, None for Tombstone.
pub fn as_bytes(&self) -> Option<Bytes> {
match self {
ValueDeletable::Value(v) | ValueDeletable::Merge(v) => Some(v.clone()),
ValueDeletable::Tombstone => None,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::format::row::SstRowEntry;
use rstest::rstest;
// Tombstone encoding:
// key_prefix_len (u16) + key_suffix_len (u16) + key_suffix + seq (u64) + flags (u8)
// = 2 + 2 + key_suffix_len + 8 + 1
// = 13 + key_suffix_len
#[rstest]
#[case(0, 18)] // key_suffix_len=5: 13 + 5 = 18
#[case(2, 16)] // key_suffix_len=3: 13 + 3 = 16
#[case(4, 14)] // key_suffix_len=1: 13 + 1 = 14
fn encoded_size_tombstone(#[case] prefix_len: usize, #[case] expected: usize) {
let entry = RowEntry::new_tombstone(b"hello", 1);
assert_eq!(entry.encoded_size(prefix_len), expected);
}
// Value encoding:
// tombstone encoding + value_len (u32) + value
// = 13 + key_suffix_len + 4 + value_len
// = 17 + key_suffix_len + value_len
#[rstest]
#[case(0, 25)] // key_suffix_len=5, value_len=3: 17 + 5 + 3 = 25
#[case(2, 23)] // key_suffix_len=3, value_len=3: 17 + 3 + 3 = 23
#[case(4, 21)] // key_suffix_len=1, value_len=3: 17 + 1 + 3 = 21
fn encoded_size_value(#[case] prefix_len: usize, #[case] expected: usize) {
let entry = RowEntry::new_value(b"hello", b"val", 1);
assert_eq!(entry.encoded_size(prefix_len), expected);
}
#[test]
fn encoded_size_matches_sst_row_entry() {
let entry = RowEntry::new_value(b"prefixkey", b"value", 1);
let sst_entry = SstRowEntry::new(
6,
Bytes::from("key"),
1,
ValueDeletable::Value(Bytes::from("value")),
None,
None,
);
assert_eq!(entry.encoded_size(6), sst_entry.size());
}
}