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neon/libs/pageserver_api/src/key.rs
Folke Behrens 9c0efba91e Bump rand crate to 0.9 (#12674)
2025-07-22 09:31:39 +00:00

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use std::fmt;
use std::ops::Range;
use anyhow::{Result, bail};
use byteorder::{BE, ByteOrder};
use bytes::Bytes;
use postgres_ffi_types::forknum::{FSM_FORKNUM, VISIBILITYMAP_FORKNUM};
use postgres_ffi_types::{Oid, RepOriginId};
use serde::{Deserialize, Serialize};
use utils::const_assert;
use crate::reltag::{BlockNumber, RelTag, SlruKind};
/// Key used in the Repository kv-store.
///
/// The Repository treats this as an opaque struct, but see the code in pgdatadir_mapping.rs
/// for what we actually store in these fields.
#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, Ord, PartialOrd, Serialize, Deserialize)]
pub struct Key {
pub field1: u8,
pub field2: u32,
pub field3: u32,
pub field4: u32,
pub field5: u8,
pub field6: u32,
}
/// When working with large numbers of Keys in-memory, it is more efficient to handle them as i128 than as
/// a struct of fields.
#[derive(
Clone, Copy, Default, Hash, PartialEq, Eq, Ord, PartialOrd, Serialize, Deserialize, Debug,
)]
pub struct CompactKey(i128);
/// The storage key size.
pub const KEY_SIZE: usize = 18;
/// The metadata key size. 2B fewer than the storage key size because field2 is not fully utilized.
/// See [`Key::to_i128`] for more information on the encoding.
pub const METADATA_KEY_SIZE: usize = 16;
/// The key prefix start range for the metadata keys. All keys with the first byte >= 0x60 is a metadata key.
pub const METADATA_KEY_BEGIN_PREFIX: u8 = 0x60;
pub const METADATA_KEY_END_PREFIX: u8 = 0x7F;
/// The (reserved) key prefix of relation sizes.
pub const RELATION_SIZE_PREFIX: u8 = 0x61;
/// The key prefix of AUX file keys.
pub const AUX_KEY_PREFIX: u8 = 0x62;
/// The key prefix of ReplOrigin keys.
pub const REPL_ORIGIN_KEY_PREFIX: u8 = 0x63;
/// The key prefix of db directory keys.
pub const DB_DIR_KEY_PREFIX: u8 = 0x64;
/// The key prefix of rel directory keys.
pub const REL_DIR_KEY_PREFIX: u8 = 0x65;
#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
pub enum RelDirExists {
Exists,
Removed,
}
#[derive(Debug)]
pub struct DecodeError;
impl fmt::Display for DecodeError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "invalid marker")
}
}
impl std::error::Error for DecodeError {}
impl RelDirExists {
/// The value of the rel directory keys that indicates the existence of a relation.
const REL_EXISTS_MARKER: Bytes = Bytes::from_static(b"r");
pub fn encode(&self) -> Bytes {
match self {
Self::Exists => Self::REL_EXISTS_MARKER.clone(),
Self::Removed => SPARSE_TOMBSTONE_MARKER.clone(),
}
}
pub fn decode_option(data: Option<impl AsRef<[u8]>>) -> Result<Self, DecodeError> {
match data {
Some(marker) if marker.as_ref() == Self::REL_EXISTS_MARKER => Ok(Self::Exists),
// Any other marker is invalid
Some(_) => Err(DecodeError),
None => Ok(Self::Removed),
}
}
pub fn decode(data: impl AsRef<[u8]>) -> Result<Self, DecodeError> {
let data = data.as_ref();
if data == Self::REL_EXISTS_MARKER {
Ok(Self::Exists)
} else if data == SPARSE_TOMBSTONE_MARKER {
Ok(Self::Removed)
} else {
Err(DecodeError)
}
}
}
/// A tombstone in the sparse keyspace, which is an empty buffer.
pub const SPARSE_TOMBSTONE_MARKER: Bytes = Bytes::from_static(b"");
/// Check if the key falls in the range of metadata keys.
pub const fn is_metadata_key_slice(key: &[u8]) -> bool {
key[0] >= METADATA_KEY_BEGIN_PREFIX && key[0] < METADATA_KEY_END_PREFIX
}
impl Key {
/// Check if the key falls in the range of metadata keys.
pub const fn is_metadata_key(&self) -> bool {
self.field1 >= METADATA_KEY_BEGIN_PREFIX && self.field1 < METADATA_KEY_END_PREFIX
}
/// Encode a metadata key to a storage key.
pub fn from_metadata_key_fixed_size(key: &[u8; METADATA_KEY_SIZE]) -> Self {
assert!(is_metadata_key_slice(key), "key not in metadata key range");
// Metadata key space ends at 0x7F so it's fine to directly convert it to i128.
Self::from_i128(i128::from_be_bytes(*key))
}
/// Encode a metadata key to a storage key.
pub fn from_metadata_key(key: &[u8]) -> Self {
Self::from_metadata_key_fixed_size(key.try_into().expect("expect 16 byte metadata key"))
}
/// Get the range of metadata keys.
pub const fn metadata_key_range() -> Range<Self> {
Key {
field1: METADATA_KEY_BEGIN_PREFIX,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}..Key {
field1: METADATA_KEY_END_PREFIX,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}
}
/// Get the range of aux keys.
pub fn metadata_aux_key_range() -> Range<Self> {
Key {
field1: AUX_KEY_PREFIX,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}..Key {
field1: AUX_KEY_PREFIX + 1,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}
}
pub fn rel_dir_sparse_key_range() -> Range<Self> {
Key {
field1: REL_DIR_KEY_PREFIX,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}..Key {
field1: REL_DIR_KEY_PREFIX + 1,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}
}
/// This function checks more extensively what keys we can take on the write path.
/// If a key beginning with 00 does not have a global/default tablespace OID, it
/// will be rejected on the write path.
#[allow(dead_code)]
pub fn is_valid_key_on_write_path_strong(&self) -> bool {
use postgres_ffi_types::constants::{DEFAULTTABLESPACE_OID, GLOBALTABLESPACE_OID};
if !self.is_i128_representable() {
return false;
}
if self.field1 == 0
&& !(self.field2 == GLOBALTABLESPACE_OID
|| self.field2 == DEFAULTTABLESPACE_OID
|| self.field2 == 0)
{
return false; // User defined tablespaces are not supported
}
true
}
/// This is a weaker version of `is_valid_key_on_write_path_strong` that simply
/// checks if the key is i128 representable. Note that some keys can be successfully
/// ingested into the pageserver, but will cause errors on generating basebackup.
pub fn is_valid_key_on_write_path(&self) -> bool {
self.is_i128_representable()
}
pub fn is_i128_representable(&self) -> bool {
self.field2 <= 0xFFFF || self.field2 == 0xFFFFFFFF || self.field2 == 0x22222222
}
/// 'field2' is used to store tablespaceid for relations and small enum numbers for other relish.
/// As long as Neon does not support tablespace (because of lack of access to local file system),
/// we can assume that only some predefined namespace OIDs are used which can fit in u16
pub fn to_i128(&self) -> i128 {
assert!(self.is_i128_representable(), "invalid key: {self}");
(((self.field1 & 0x7F) as i128) << 120)
| (((self.field2 & 0xFFFF) as i128) << 104)
| ((self.field3 as i128) << 72)
| ((self.field4 as i128) << 40)
| ((self.field5 as i128) << 32)
| self.field6 as i128
}
pub const fn from_i128(x: i128) -> Self {
Key {
field1: ((x >> 120) & 0x7F) as u8,
field2: ((x >> 104) & 0xFFFF) as u32,
field3: (x >> 72) as u32,
field4: (x >> 40) as u32,
field5: (x >> 32) as u8,
field6: x as u32,
}
}
pub fn to_compact(&self) -> CompactKey {
CompactKey(self.to_i128())
}
pub fn from_compact(k: CompactKey) -> Self {
Self::from_i128(k.0)
}
pub const fn next(&self) -> Key {
self.add(1)
}
pub const fn add(&self, x: u32) -> Key {
let mut key = *self;
let r = key.field6.overflowing_add(x);
key.field6 = r.0;
if r.1 {
let r = key.field5.overflowing_add(1);
key.field5 = r.0;
if r.1 {
let r = key.field4.overflowing_add(1);
key.field4 = r.0;
if r.1 {
let r = key.field3.overflowing_add(1);
key.field3 = r.0;
if r.1 {
let r = key.field2.overflowing_add(1);
key.field2 = r.0;
if r.1 {
let r = key.field1.overflowing_add(1);
key.field1 = r.0;
assert!(!r.1);
}
}
}
}
}
key
}
/// Convert a 18B slice to a key. This function should not be used for 16B metadata keys because `field2` is handled differently.
/// Use [`Key::from_i128`] instead if you want to handle 16B keys (i.e., metadata keys). There are some restrictions on `field2`,
/// and therefore not all 18B slices are valid page server keys.
pub fn from_slice(b: &[u8]) -> Self {
Key {
field1: b[0],
field2: u32::from_be_bytes(b[1..5].try_into().unwrap()),
field3: u32::from_be_bytes(b[5..9].try_into().unwrap()),
field4: u32::from_be_bytes(b[9..13].try_into().unwrap()),
field5: b[13],
field6: u32::from_be_bytes(b[14..18].try_into().unwrap()),
}
}
/// Convert a key to a 18B slice. This function should not be used for getting a 16B metadata key because `field2` is handled differently.
/// Use [`Key::to_i128`] instead if you want to get a 16B key (i.e., metadata keys).
pub fn write_to_byte_slice(&self, buf: &mut [u8]) {
buf[0] = self.field1;
BE::write_u32(&mut buf[1..5], self.field2);
BE::write_u32(&mut buf[5..9], self.field3);
BE::write_u32(&mut buf[9..13], self.field4);
buf[13] = self.field5;
BE::write_u32(&mut buf[14..18], self.field6);
}
}
impl CompactKey {
pub fn raw(&self) -> i128 {
self.0
}
}
impl From<i128> for CompactKey {
fn from(value: i128) -> Self {
Self(value)
}
}
impl fmt::Display for Key {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"{:02X}{:08X}{:08X}{:08X}{:02X}{:08X}",
self.field1, self.field2, self.field3, self.field4, self.field5, self.field6
)
}
}
impl fmt::Display for CompactKey {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let k = Key::from_compact(*self);
k.fmt(f)
}
}
impl Key {
pub const MIN: Key = Key {
field1: u8::MIN,
field2: u32::MIN,
field3: u32::MIN,
field4: u32::MIN,
field5: u8::MIN,
field6: u32::MIN,
};
pub const MAX: Key = Key {
field1: u8::MAX,
field2: u32::MAX,
field3: u32::MAX,
field4: u32::MAX,
field5: u8::MAX,
field6: u32::MAX,
};
pub fn from_hex(s: &str) -> Result<Self> {
if s.len() != 36 {
bail!("parse error");
}
Ok(Key {
field1: u8::from_str_radix(&s[0..2], 16)?,
field2: u32::from_str_radix(&s[2..10], 16)?,
field3: u32::from_str_radix(&s[10..18], 16)?,
field4: u32::from_str_radix(&s[18..26], 16)?,
field5: u8::from_str_radix(&s[26..28], 16)?,
field6: u32::from_str_radix(&s[28..36], 16)?,
})
}
}
// Layout of the Key address space
//
// The Key struct, used to address the underlying key-value store, consists of
// 18 bytes, split into six fields. See 'Key' in repository.rs. We need to map
// all the data and metadata keys into those 18 bytes.
//
// Principles for the mapping:
//
// - Things that are often accessed or modified together, should be close to
// each other in the key space. For example, if a relation is extended by one
// block, we create a new key-value pair for the block data, and update the
// relation size entry. Because of that, the RelSize key comes after all the
// RelBlocks of a relation: the RelSize and the last RelBlock are always next
// to each other.
//
// The key space is divided into four major sections, identified by the first
// byte, and the form a hierarchy:
//
// 00 Relation data and metadata
//
// DbDir () -> (dbnode, spcnode)
// Filenodemap
// RelDir -> relnode forknum
// RelBlocks
// RelSize
//
// 01 SLRUs
//
// SlruDir kind
// SlruSegBlocks segno
// SlruSegSize
//
// 02 pg_twophase
//
// 03 misc
// Controlfile
// checkpoint
// pg_version
//
// 04 aux files
//
// Below is a full list of the keyspace allocation:
//
// DbDir:
// 00 00000000 00000000 00000000 00 00000000
//
// Filenodemap:
// 00 SPCNODE DBNODE 00000000 00 00000000
//
// RelDir:
// 00 SPCNODE DBNODE 00000000 00 00000001 (Postgres never uses relfilenode 0)
//
// RelBlock:
// 00 SPCNODE DBNODE RELNODE FORK BLKNUM
//
// RelSize:
// 00 SPCNODE DBNODE RELNODE FORK FFFFFFFF
//
// SlruDir:
// 01 kind 00000000 00000000 00 00000000
//
// SlruSegBlock:
// 01 kind 00000001 SEGNO 00 BLKNUM
//
// SlruSegSize:
// 01 kind 00000001 SEGNO 00 FFFFFFFF
//
// TwoPhaseDir:
// 02 00000000 00000000 00000000 00 00000000
//
// TwoPhaseFile:
//
// 02 00000000 00000000 00XXXXXX XX XXXXXXXX
//
// \______XID_________/
//
// The 64-bit XID is stored a little awkwardly in field6, field5 and
// field4. PostgreSQL v16 and below only stored a 32-bit XID, which
// fit completely in field6, but starting with PostgreSQL v17, a full
// 64-bit XID is used. Most pageserver code that accesses
// TwoPhaseFiles now deals with 64-bit XIDs even on v16, the high bits
// are just unused.
//
// ControlFile:
// 03 00000000 00000000 00000000 00 00000000
//
// Checkpoint:
// 03 00000000 00000000 00000000 00 00000001
//
// AuxFiles:
// 03 00000000 00000000 00000000 00 00000002
//
//-- Section 01: relation data and metadata
pub const DBDIR_KEY: Key = Key {
field1: 0x00,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
};
#[inline(always)]
pub fn dbdir_key_range(spcnode: Oid, dbnode: Oid) -> Range<Key> {
Key {
field1: 0x00,
field2: spcnode,
field3: dbnode,
field4: 0,
field5: 0,
field6: 0,
}..Key {
field1: 0x00,
field2: spcnode,
field3: dbnode,
field4: 0xffffffff,
field5: 0xff,
field6: 0xffffffff,
}
}
#[inline(always)]
pub fn relmap_file_key(spcnode: Oid, dbnode: Oid) -> Key {
Key {
field1: 0x00,
field2: spcnode,
field3: dbnode,
field4: 0,
field5: 0,
field6: 0,
}
}
#[inline(always)]
pub fn rel_dir_to_key(spcnode: Oid, dbnode: Oid) -> Key {
Key {
field1: 0x00,
field2: spcnode,
field3: dbnode,
field4: 0,
field5: 0,
field6: 1,
}
}
#[inline(always)]
pub fn rel_tag_sparse_key(spcnode: Oid, dbnode: Oid, relnode: Oid, forknum: u8) -> Key {
Key {
field1: REL_DIR_KEY_PREFIX,
field2: spcnode,
field3: dbnode,
field4: relnode,
field5: forknum,
field6: 1,
}
}
pub fn rel_tag_sparse_key_range(spcnode: Oid, dbnode: Oid) -> Range<Key> {
Key {
field1: REL_DIR_KEY_PREFIX,
field2: spcnode,
field3: dbnode,
field4: 0,
field5: 0,
field6: 0,
}..Key {
field1: REL_DIR_KEY_PREFIX,
field2: spcnode,
field3: dbnode,
field4: u32::MAX,
field5: u8::MAX,
field6: u32::MAX,
} // it's fine to exclude the last key b/c we only use field6 == 1
}
#[inline(always)]
pub fn rel_block_to_key(rel: RelTag, blknum: BlockNumber) -> Key {
Key {
field1: 0x00,
field2: rel.spcnode,
field3: rel.dbnode,
field4: rel.relnode,
field5: rel.forknum,
field6: blknum,
}
}
#[inline(always)]
pub fn rel_size_to_key(rel: RelTag) -> Key {
Key {
field1: 0x00,
field2: rel.spcnode,
field3: rel.dbnode,
field4: rel.relnode,
field5: rel.forknum,
field6: 0xffff_ffff,
}
}
impl Key {
#[inline(always)]
pub fn is_rel_size_key(&self) -> bool {
self.field1 == 0 && self.field6 == u32::MAX
}
}
#[inline(always)]
pub fn rel_key_range(rel: RelTag) -> Range<Key> {
Key {
field1: 0x00,
field2: rel.spcnode,
field3: rel.dbnode,
field4: rel.relnode,
field5: rel.forknum,
field6: 0,
}..Key {
field1: 0x00,
field2: rel.spcnode,
field3: rel.dbnode,
field4: rel.relnode,
field5: rel.forknum + 1,
field6: 0,
}
}
//-- Section 02: SLRUs
#[inline(always)]
pub fn slru_dir_to_key(kind: SlruKind) -> Key {
Key {
field1: 0x01,
field2: match kind {
SlruKind::Clog => 0x00,
SlruKind::MultiXactMembers => 0x01,
SlruKind::MultiXactOffsets => 0x02,
},
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}
}
#[inline(always)]
pub fn slru_dir_kind(key: &Key) -> Option<Result<SlruKind, u32>> {
if key.field1 == 0x01
&& key.field3 == 0
&& key.field4 == 0
&& key.field5 == 0
&& key.field6 == 0
{
match key.field2 {
0 => Some(Ok(SlruKind::Clog)),
1 => Some(Ok(SlruKind::MultiXactMembers)),
2 => Some(Ok(SlruKind::MultiXactOffsets)),
x => Some(Err(x)),
}
} else {
None
}
}
#[inline(always)]
pub fn slru_block_to_key(kind: SlruKind, segno: u32, blknum: BlockNumber) -> Key {
Key {
field1: 0x01,
field2: match kind {
SlruKind::Clog => 0x00,
SlruKind::MultiXactMembers => 0x01,
SlruKind::MultiXactOffsets => 0x02,
},
field3: 1,
field4: segno,
field5: 0,
field6: blknum,
}
}
#[inline(always)]
pub fn slru_segment_size_to_key(kind: SlruKind, segno: u32) -> Key {
Key {
field1: 0x01,
field2: match kind {
SlruKind::Clog => 0x00,
SlruKind::MultiXactMembers => 0x01,
SlruKind::MultiXactOffsets => 0x02,
},
field3: 1,
field4: segno,
field5: 0,
field6: 0xffff_ffff,
}
}
impl Key {
pub fn is_slru_segment_size_key(&self) -> bool {
self.field1 == 0x01
&& self.field2 < 0x03
&& self.field3 == 0x01
&& self.field5 == 0
&& self.field6 == u32::MAX
}
pub fn is_slru_dir_key(&self) -> bool {
slru_dir_kind(self).is_some()
}
}
#[inline(always)]
pub fn slru_segment_key_range(kind: SlruKind, segno: u32) -> Range<Key> {
let field2 = match kind {
SlruKind::Clog => 0x00,
SlruKind::MultiXactMembers => 0x01,
SlruKind::MultiXactOffsets => 0x02,
};
Key {
field1: 0x01,
field2,
field3: 1,
field4: segno,
field5: 0,
field6: 0,
}..Key {
field1: 0x01,
field2,
field3: 1,
field4: segno,
field5: 1,
field6: 0,
}
}
//-- Section 03: pg_twophase
pub const TWOPHASEDIR_KEY: Key = Key {
field1: 0x02,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
};
#[inline(always)]
pub fn twophase_file_key(xid: u64) -> Key {
Key {
field1: 0x02,
field2: 0,
field3: 0,
field4: ((xid & 0xFFFFFF0000000000) >> 40) as u32,
field5: ((xid & 0x000000FF00000000) >> 32) as u8,
field6: (xid & 0x00000000FFFFFFFF) as u32,
}
}
#[inline(always)]
pub fn twophase_key_range(xid: u64) -> Range<Key> {
// 64-bit XIDs really should not overflow
let (next_xid, overflowed) = xid.overflowing_add(1);
Key {
field1: 0x02,
field2: 0,
field3: 0,
field4: ((xid & 0xFFFFFF0000000000) >> 40) as u32,
field5: ((xid & 0x000000FF00000000) >> 32) as u8,
field6: (xid & 0x00000000FFFFFFFF) as u32,
}..Key {
field1: 0x02,
field2: 0,
field3: u32::from(overflowed),
field4: ((next_xid & 0xFFFFFF0000000000) >> 40) as u32,
field5: ((next_xid & 0x000000FF00000000) >> 32) as u8,
field6: (next_xid & 0x00000000FFFFFFFF) as u32,
}
}
//-- Section 03: Control file
pub const CONTROLFILE_KEY: Key = Key {
field1: 0x03,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
};
pub const CHECKPOINT_KEY: Key = Key {
field1: 0x03,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 1,
};
pub const AUX_FILES_KEY: Key = Key {
field1: 0x03,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 2,
};
#[inline(always)]
pub fn repl_origin_key(origin_id: RepOriginId) -> Key {
Key {
field1: REPL_ORIGIN_KEY_PREFIX,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: origin_id as u32,
}
}
/// Get the range of replorigin keys.
pub fn repl_origin_key_range() -> Range<Key> {
Key {
field1: REPL_ORIGIN_KEY_PREFIX,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}..Key {
field1: REPL_ORIGIN_KEY_PREFIX,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0x10000,
}
}
// Reverse mappings for a few Keys.
// These are needed by WAL redo manager.
/// Non inherited range for vectored get.
pub const NON_INHERITED_RANGE: Range<Key> = AUX_FILES_KEY..AUX_FILES_KEY.next();
/// Sparse keyspace range for vectored get. Missing key error will be ignored for this range.
pub const SPARSE_RANGE: Range<Key> = Key::metadata_key_range();
impl Key {
// AUX_FILES currently stores only data for logical replication (slots etc), and
// we don't preserve these on a branch because safekeepers can't follow timeline
// switch (and generally it likely should be optional), so ignore these.
#[inline(always)]
pub fn is_inherited_key(self) -> bool {
if self.is_sparse() {
self.is_inherited_sparse_key()
} else {
!NON_INHERITED_RANGE.contains(&self)
}
}
#[inline(always)]
pub fn is_sparse(self) -> bool {
self.field1 >= METADATA_KEY_BEGIN_PREFIX && self.field1 < METADATA_KEY_END_PREFIX
}
/// Check if the key belongs to the inherited keyspace.
fn is_inherited_sparse_key(self) -> bool {
debug_assert!(self.is_sparse());
self.field1 == RELATION_SIZE_PREFIX
}
pub const fn sparse_non_inherited_keyspace() -> Range<Key> {
// The two keys are adjacent; if we will have non-adjancent keys in the future, we should return a keyspace
const_assert!(AUX_KEY_PREFIX + 1 == REPL_ORIGIN_KEY_PREFIX);
Key {
field1: AUX_KEY_PREFIX,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}..Key {
field1: REPL_ORIGIN_KEY_PREFIX + 1,
field2: 0,
field3: 0,
field4: 0,
field5: 0,
field6: 0,
}
}
#[inline(always)]
pub fn is_rel_fsm_block_key(self) -> bool {
self.field1 == 0x00
&& self.field4 != 0
&& self.field5 == FSM_FORKNUM
&& self.field6 != 0xffffffff
}
#[inline(always)]
pub fn is_rel_vm_block_key(self) -> bool {
self.field1 == 0x00
&& self.field4 != 0
&& self.field5 == VISIBILITYMAP_FORKNUM
&& self.field6 != 0xffffffff
}
#[inline(always)]
pub fn to_slru_block(self) -> anyhow::Result<(SlruKind, u32, BlockNumber)> {
Ok(match self.field1 {
0x01 => {
let kind = match self.field2 {
0x00 => SlruKind::Clog,
0x01 => SlruKind::MultiXactMembers,
0x02 => SlruKind::MultiXactOffsets,
_ => anyhow::bail!("unrecognized slru kind 0x{:02x}", self.field2),
};
let segno = self.field4;
let blknum = self.field6;
(kind, segno, blknum)
}
_ => anyhow::bail!("unexpected value kind 0x{:02x}", self.field1),
})
}
#[inline(always)]
pub fn is_slru_block_key(self) -> bool {
self.field1 == 0x01 // SLRU-related
&& self.field3 == 0x00000001 // but not SlruDir
&& self.field6 != 0xffffffff // and not SlruSegSize
}
#[inline(always)]
pub fn is_rel_block_key(&self) -> bool {
self.field1 == 0x00 && self.field4 != 0 && self.field6 != 0xffffffff
}
#[inline(always)]
pub fn is_rel_block_of_rel(&self, rel: Oid) -> bool {
self.is_rel_block_key() && self.field4 == rel
}
#[inline(always)]
pub fn is_rel_dir_key(&self) -> bool {
self.field1 == 0x00
&& self.field2 != 0
&& self.field3 != 0
&& self.field4 == 0
&& self.field5 == 0
&& self.field6 == 1
}
#[inline(always)]
pub fn is_aux_file_key(&self) -> bool {
self.field1 == AUX_KEY_PREFIX
}
/// Guaranteed to return `Ok()` if [`Self::is_rel_block_key`] returns `true` for `key`.
#[inline(always)]
pub fn to_rel_block(self) -> Result<(RelTag, BlockNumber), ToRelBlockError> {
Ok(match self.field1 {
0x00 => (
RelTag {
spcnode: self.field2,
dbnode: self.field3,
relnode: self.field4,
forknum: self.field5,
},
self.field6,
),
_ => return Err(ToRelBlockError(self.field1)),
})
}
}
impl std::str::FromStr for Key {
type Err = anyhow::Error;
fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
Self::from_hex(s)
}
}
#[derive(Debug)]
pub struct ToRelBlockError(u8);
impl fmt::Display for ToRelBlockError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "unexpected value kind 0x{:02x}", self.0)
}
}
impl std::error::Error for ToRelBlockError {}
#[cfg(test)]
mod tests {
use std::str::FromStr;
use rand::{Rng, SeedableRng};
use super::AUX_KEY_PREFIX;
use crate::key::{Key, is_metadata_key_slice};
#[test]
fn display_fromstr_bijection() {
let mut rng = rand::rngs::StdRng::seed_from_u64(42);
let key = Key {
field1: rng.random(),
field2: rng.random(),
field3: rng.random(),
field4: rng.random(),
field5: rng.random(),
field6: rng.random(),
};
assert_eq!(key, Key::from_str(&format!("{key}")).unwrap());
}
#[test]
fn test_metadata_keys() {
let mut metadata_key = vec![AUX_KEY_PREFIX];
metadata_key.extend_from_slice(&[0xFF; 15]);
let encoded_key = Key::from_metadata_key(&metadata_key);
let output_key = encoded_key.to_i128().to_be_bytes();
assert_eq!(metadata_key, output_key);
assert!(encoded_key.is_metadata_key());
assert!(is_metadata_key_slice(&metadata_key));
}
#[test]
fn test_possible_largest_key() {
Key::from_i128(0x7FFF_FFFF_FFFF_FFFF_FFFF_FFFF_FFFF_FFFF);
// TODO: put this key into the system and see if anything breaks.
}
}
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