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Copy pathdict.rs
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1195 lines (1128 loc) · 43.1 KB
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//! The dictionary tree (DICT, spec §5) and the encoding of facts into keys.
//!
//! [`DictReader`] looks ids up in a committed DICT tree and translates index
//! entries back into [`Fact`]s, memoising every lookup for its own lifetime, so
//! memory is bounded by one read's results.
//!
//! [`Encoder`] turns pending facts into index keys at checkpoint time, in
//! pending (WAL) order: it assigns new eids and iids from the meta's counters,
//! records each transaction's timestamp, and deduplicates long values against
//! the committed ones and against each other. Ids are never persisted before the
//! commit that writes their DICT entries, so assigning them here is crash-safe.
//! Encoding runs in two phases so the committed reader and the page writes
//! never borrow the backend at once: [`Encoder::stage`] reads, then
//! [`Encoder::finish`] writes the new long values and builds the keys.
use crate::error::{ErrorCode, bail_coded, err_coded};
use crate::graph::types::{Fact, Value};
use crate::storage::StorageBackend;
use crate::storage::btree;
use crate::storage::cache::PageCache;
use crate::storage::keys::{self, Index, KeyFact, KeyValue, SHORT_STRING_MAX, ValueRef};
use crate::storage::node::Entry;
use crate::storage::page::PageAllocator;
use crate::storage::value_pages::{ValueWriter, read_value};
use anyhow::Result;
use std::collections::HashMap;
use uuid::Uuid;
/// Entries a [`SharedDictCache`] map holds before it is cleared.
const SHARED_CACHE_LIMIT: usize = 65_536;
pub(crate) fn check_eids(eids: &[u64]) -> Result<()> {
if eids.iter().zip(eids.iter().skip(1)).any(|(a, b)| a >= b) {
bail_coded!(ErrorCode::Int049, "entity ids not sorted and distinct");
}
Ok(())
}
fn decode_uuid(eid: u64, bytes: Option<&[u8]>) -> Result<Uuid> {
let bytes = bytes.ok_or_else(|| err_coded!(ErrorCode::Stg036, format!("entity id {eid}")))?;
Uuid::from_slice(bytes)
.map_err(|_| err_coded!(ErrorCode::Stg036, format!("entity id {eid}: bad UUID")))
}
/// Ident and transaction lookups shared by every read of one committed meta.
/// They never change once committed, and there are few of them compared with
/// entities, so they are cached across reads; each map is cleared when it
/// reaches [`SHARED_CACHE_LIMIT`] entries.
#[derive(Default)]
pub struct SharedDictCache {
iids: std::sync::RwLock<HashMap<String, u32>>,
names: std::sync::RwLock<HashMap<u32, String>>,
tx_ids: std::sync::RwLock<HashMap<u64, u64>>,
}
fn shared_get<K: std::hash::Hash + Eq, V: Clone>(
map: &std::sync::RwLock<HashMap<K, V>>,
key: &K,
) -> Option<V> {
map.read().ok()?.get(key).cloned()
}
fn shared_put<K: std::hash::Hash + Eq, V>(
map: &std::sync::RwLock<HashMap<K, V>>,
key: K,
value: V,
) {
if let Ok(mut m) = map.write() {
if m.len() >= SHARED_CACHE_LIMIT {
m.clear();
}
m.insert(key, value);
}
}
/// Lookups in a committed DICT tree, memoised.
pub struct DictReader<'a> {
root: u64,
backend: &'a dyn StorageBackend,
cache: &'a PageCache,
shared: Option<&'a SharedDictCache>,
uuids: HashMap<u64, Uuid>,
names: HashMap<u32, String>,
tx_ids: HashMap<u64, u64>,
long_values: HashMap<ValueRef, Vec<u8>>,
}
impl<'a> DictReader<'a> {
/// A reader over the DICT tree at `root` (0: the empty dictionary).
pub fn new(root: u64, backend: &'a dyn StorageBackend, cache: &'a PageCache) -> Self {
DictReader {
root,
backend,
cache,
shared: None,
uuids: HashMap::new(),
names: HashMap::new(),
tx_ids: HashMap::new(),
long_values: HashMap::new(),
}
}
/// Consult and fill `shared` for idents and transaction timestamps.
pub fn with_shared(mut self, shared: &'a SharedDictCache) -> Self {
self.shared = Some(shared);
self
}
/// Record a known `eid → uuid` pair (the caller looked the eid up by it).
#[cfg(test)]
pub fn seed_entity(&mut self, eid: u64, uuid: Uuid) {
self.uuids.insert(eid, uuid);
}
/// Record a known `iid → ident` pair.
#[cfg(test)]
pub fn seed_ident(&mut self, iid: u32, ident: &str) {
self.names.insert(iid, ident.to_string());
}
fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>> {
if self.root == 0 {
return Ok(None);
}
btree::get(self.root, key, self.backend, self.cache)
}
/// The eid of `uuid`, if it has one.
pub fn eid_of(&self, uuid: &Uuid) -> Result<Option<u64>> {
self.get(&keys::dict_uuid_key(uuid))?
.map(|v| keys::read_uint_bytes(&v))
.transpose()
}
/// The iid of `ident`, if it has one.
pub fn iid_of(&self, ident: &str) -> Result<Option<u32>> {
if let Some(i) = self
.shared
.and_then(|c| shared_get(&c.iids, &ident.to_string()))
{
return Ok(Some(i));
}
let found = self
.get(&keys::dict_ident_key(ident))?
.map(|v| {
u32::try_from(keys::read_uint_bytes(&v)?)
.map_err(|_| err_coded!(ErrorCode::Int049, "iid out of range"))
})
.transpose()?;
if let (Some(i), Some(c)) = (found, self.shared) {
shared_put(&c.iids, ident.to_string(), i);
}
Ok(found)
}
/// The timestamp recorded for `tx_count`, if any.
pub fn tx_id_lookup(&mut self, tx_count: u64) -> Result<Option<u64>> {
if let Some(t) = self.tx_ids.get(&tx_count) {
return Ok(Some(*t));
}
if let Some(t) = self.shared.and_then(|c| shared_get(&c.tx_ids, &tx_count)) {
self.tx_ids.insert(tx_count, t);
return Ok(Some(t));
}
let found = self
.get(&keys::dict_tx_key(tx_count))?
.map(|v| keys::read_uint_bytes(&v))
.transpose()?;
if let Some(t) = found {
self.tx_ids.insert(tx_count, t);
if let Some(c) = self.shared {
shared_put(&c.tx_ids, tx_count, t);
}
}
Ok(found)
}
pub fn uuid_of(&mut self, eid: u64) -> Result<Uuid> {
if let Some(u) = self.uuids.get(&eid) {
return Ok(*u);
}
let u = self.read_uuid(eid)?;
self.uuids.insert(eid, u);
Ok(u)
}
fn read_uuid(&self, eid: u64) -> Result<Uuid> {
let bytes = self.get(&keys::dict_eid_key(eid))?;
decode_uuid(eid, bytes.as_deref())
}
/// Dense chunks walk existing DICT leaves once; sparse/small chunks retain
/// scalar exact-key reads. Neither path populates an ephemeral UUID map.
pub(crate) fn uuids_of(
&self,
eids: &[u64],
visit: &mut dyn FnMut(u64, Uuid) -> Result<()>,
) -> Result<()> {
check_eids(eids)?;
if eids.is_empty() {
return Ok(());
}
if self.root == 0 {
return decode_uuid(eids.first().copied().unwrap_or(0), None).map(|_| ());
}
for chunk in eids.chunks(1024) {
let first = chunk.first().copied().unwrap_or(0);
let last = chunk.last().copied().unwrap_or(first);
let span_limit = u64::try_from(chunk.len())
.unwrap_or(u64::MAX)
.saturating_mul(2);
if chunk.len() < 64 || last.saturating_sub(first) > span_limit {
for &eid in chunk {
visit(eid, self.read_uuid(eid)?)?;
}
continue;
}
let start = keys::dict_eid_key(first);
let mut cursor =
btree::LeafCursor::new(self.root, Some(&start), self.backend, self.cache)?;
for &eid in chunk {
let mut matched = false;
while let Some((key, bytes)) = cursor.next_ref()? {
let Some(rest) = key.strip_prefix(&[keys::DICT_EID_TO_UUID]) else {
break;
};
let found = keys::read_uint_bytes(rest)?;
if found < eid {
continue;
}
if found == eid {
visit(eid, decode_uuid(eid, Some(bytes))?)?;
matched = true;
}
break;
}
if !matched {
return decode_uuid(eid, None).map(|_| ());
}
}
}
Ok(())
}
pub fn name_of(&mut self, iid: u32) -> Result<String> {
if let Some(n) = self.names.get(&iid) {
return Ok(n.clone());
}
if let Some(n) = self.shared.and_then(|c| shared_get(&c.names, &iid)) {
self.names.insert(iid, n.clone());
return Ok(n);
}
let v = self
.get(&keys::dict_iid_key(iid))?
.ok_or_else(|| err_coded!(ErrorCode::Stg036, format!("ident id {iid}")))?;
let n = String::from_utf8(v)
.map_err(|_| err_coded!(ErrorCode::Stg036, format!("ident id {iid}: not UTF-8")))?;
self.names.insert(iid, n.clone());
if let Some(c) = self.shared {
shared_put(&c.names, iid, n.clone());
}
Ok(n)
}
pub fn tx_id_of(&mut self, tx_count: u64) -> Result<u64> {
self.tx_id_lookup(tx_count)?
.ok_or_else(|| err_coded!(ErrorCode::Stg036, format!("transaction {tx_count}")))
}
/// The bytes of the long value at `vref`: a long string's, or a long
/// set's element encoding (#316).
pub fn long_bytes(&mut self, vref: ValueRef) -> Result<Vec<u8>> {
if let Some(b) = self.long_values.get(&vref) {
return Ok(b.clone());
}
let bytes = read_value(vref, self.backend, self.cache)?;
self.long_values.insert(vref, bytes.clone());
Ok(bytes)
}
pub fn long_value(&mut self, vref: ValueRef) -> Result<String> {
String::from_utf8(self.long_bytes(vref)?).map_err(|_| {
err_coded!(
ErrorCode::Stg036,
format!("long value {}:{} not UTF-8", vref.page, vref.slot)
)
})
}
/// The committed long value with these bytes, if any (§6.3 dedup). It
/// compares bytes, so a long string and a long set never fail on each
/// other's records.
pub fn find_long_bytes(&mut self, bytes: &[u8]) -> Result<Option<ValueRef>> {
if self.root == 0 {
return Ok(None);
}
let prefix = keys::dict_long_value_prefix(keys::hash64(bytes));
for (k, _) in btree::prefix_scan(self.root, &prefix, self.backend, self.cache)? {
let vref = keys::dict_long_value_ref(&k)?;
if self.long_bytes(vref)? == bytes {
return Ok(Some(vref));
}
}
Ok(None)
}
/// The committed long string equal to `s`, if any.
pub fn find_long_value(&mut self, s: &str) -> Result<Option<ValueRef>> {
self.find_long_bytes(s.as_bytes())
}
/// The set a committed key value holds, `None` if it is not a set.
pub fn set_of(&mut self, v: &KeyValue) -> Result<Option<crate::graph::types::ValueSet>> {
let long = match v {
KeyValue::LongSet { vref, .. } => Some(self.long_bytes(*vref)?),
_ => None,
};
// `decode_set` takes three closures over one reader: read the long
// bytes first, then name the elements one lookup at a time.
let names = std::cell::RefCell::new(self);
keys::decode_set(
v,
|_| long.ok_or_else(|| err_coded!(ErrorCode::Int049, "long set without bytes")),
|iid| names.borrow_mut().name_of(iid),
|eid| names.borrow_mut().uuid_of(eid),
)
}
/// Translate an index entry back into a fact.
pub fn fact(&mut self, kf: &KeyFact) -> Result<Fact> {
let value = match &kf.v {
KeyValue::Null => Value::Null,
KeyValue::Bool(b) => Value::Boolean(*b),
KeyValue::Int(n) => Value::Integer(*n),
KeyValue::Float(f) => Value::Float(*f),
KeyValue::Str(s) => Value::String(s.clone()),
KeyValue::LongStr { vref, .. } => Value::String(self.long_value(*vref)?),
KeyValue::Keyword(iid) => Value::Keyword(self.name_of(*iid)?),
KeyValue::Ref(eid) => Value::Ref(self.uuid_of(*eid)?),
KeyValue::Set(_) | KeyValue::LongSet { .. } => Value::Set(
self.set_of(&kf.v)?
.ok_or_else(|| err_coded!(ErrorCode::Int049, "set key without a set"))?,
),
};
Ok(Fact {
entity: self.uuid_of(kf.e)?,
attribute: self.name_of(kf.a)?,
value,
tx_id: self.tx_id_of(kf.tx_count)?,
tx_count: kf.tx_count,
valid_from: kf.vf,
valid_to: kf.vt,
asserted: kf.asserted,
})
}
}
/// A value after staging: ready, or a long value still to be written.
enum StagedValue {
Ready(KeyValue),
/// The index of a record this checkpoint writes, and whether this value
/// is a set. A string and a set with the same bytes share the record;
/// each keeps its own kind (#316).
NewLong(usize, bool),
}
/// The key form of a long string's or set's `bytes` stored at `vref`.
fn long_key(bytes: &[u8], set: bool, vref: ValueRef) -> KeyValue {
if set {
keys::long_set(bytes, vref)
} else {
keys::long_bytes(bytes, vref)
}
}
/// A fact with its ids assigned.
struct Staged {
e: u64,
a: u32,
v: StagedValue,
tx_count: u64,
vf: i64,
vt: i64,
asserted: bool,
}
/// What one checkpoint adds: sorted, distinct entries per tree.
pub struct Encoded {
/// EAVT, AEVT, AVET, VAET entries, in [`Index::ALL`] order.
pub index: [Vec<Entry>; 4],
pub dict: Vec<Entry>,
pub next_eid: u64,
pub next_iid: u32,
}
/// Assigns ids and builds keys for one checkpoint's facts.
pub struct Encoder {
next_eid: u64,
next_iid: u32,
eids: HashMap<Uuid, u64>,
iids: HashMap<String, u32>,
txs: HashMap<u64, u64>,
new_long: HashMap<Vec<u8>, usize>,
/// Long values this checkpoint writes: a string's bytes, or a set's
/// element encoding (#316).
new_values: Vec<Vec<u8>>,
dict: Vec<Entry>,
staged: Vec<Staged>,
}
impl Encoder {
/// An encoder whose new ids start at the meta's counters (0 means 1).
pub fn new(next_eid: u64, next_iid: u32) -> Self {
Encoder {
next_eid: next_eid.max(1),
next_iid: next_iid.max(1),
eids: HashMap::new(),
iids: HashMap::new(),
txs: HashMap::new(),
new_long: HashMap::new(),
new_values: Vec::new(),
dict: Vec::new(),
staged: Vec::new(),
}
}
fn eid(&mut self, uuid: Uuid, dict: &DictReader<'_>) -> Result<u64> {
if let Some(e) = self.eids.get(&uuid) {
return Ok(*e);
}
let e = match dict.eid_of(&uuid)? {
Some(e) => e,
None => {
let e = self.next_eid;
self.next_eid = e
.checked_add(1)
.ok_or_else(|| err_coded!(ErrorCode::Int048, "entity ids exhausted"))?;
self.dict
.push((keys::dict_uuid_key(&uuid), keys::uint_bytes(e)));
self.dict
.push((keys::dict_eid_key(e), uuid.as_bytes().to_vec()));
e
}
};
self.eids.insert(uuid, e);
Ok(e)
}
fn iid(&mut self, ident: &str, dict: &DictReader<'_>) -> Result<u32> {
if let Some(i) = self.iids.get(ident) {
return Ok(*i);
}
if ident.len() > keys::MAX_IDENT_BYTES
8
{
10BC8
bail_coded!(ErrorCode::Wal003, ident.len(), keys::MAX_IDENT_BYTES);
}
let i = match dict.iid_of(ident)? {
Some(i) => i,
None => {
let i = self.next_iid;
self.next_iid = i
.checked_add(1)
.ok_or_else(|| err_coded!(ErrorCode::Int048, "ident ids exhausted"))?;
self.dict
.push((keys::dict_ident_key(ident), keys::uint_bytes(u64::from(i))));
self.dict
.push((keys::dict_iid_key(i), ident.as_bytes().to_vec()));
i
}
};
self.iids.insert(ident.to_string(), i);
Ok(i)
}
fn tx(&mut self, tx_count: u64, tx_id: u64, dict: &mut DictReader<'_>) -> Result<()> {
let known = match self.txs.get(&tx_count) {
Some(t) => Some(*t),
None => dict.tx_id_lookup(tx_count)?,
};
match known {
Some(t) if t != tx_id => bail_coded!(ErrorCode::Stg037, tx_count, t, tx_id),
Some(_) => {}
None => self
.dict
.push((keys::dict_tx_key(tx_count), keys::uint_bytes(tx_id))),
}
self.txs.insert(tx_count, tx_id);
Ok(())
}
fn value(&mut self, v: &Value, dict: &mut DictReader<'_>) -> Result<StagedValue> {
Ok(StagedValue::Ready(match v {
Value::Null => KeyValue::Null,
Value::Boolean(b) => KeyValue::Bool(*b),
Value::Integer(n) => KeyValue::Int(*n),
Value::Float(f) => KeyValue::Float(*f),
Value::String(s) if s.len() <= SHORT_STRING_MAX => KeyValue::Str(s.clone()),
Value::String(s) => return self.long(s.as_bytes(), false, dict),
Value::Keyword(k) => KeyValue::Keyword(self.iid(k, dict)?),
Value::Ref(u) => KeyValue::Ref(self.eid(*u, dict)?),
Value::Set(set) => {
let mut elements = Vec::with_capacity(set.len());
for e in set {
elements.push(match e {
// A string element is written in full, whatever its length.
Value::String(s) => KeyValue::Str(s.clone()),
e => match self.value(e, dict)? {
StagedValue::Ready(k) => k,
StagedValue::NewLong(..) => {
bail_coded!(ErrorCode::Int049, "set element staged as long")
}
},
});
}
let bytes = keys::set_elements(&elements);
if bytes.len() <= SHORT_STRING_MAX {
KeyValue::Set(bytes)
} else {
return self.long(&bytes, true, dict);
}
}
}))
}
/// The staged form of a long value: an existing record's ref, or a new
/// record written by [`Encoder::finish`].
fn long(&mut self, bytes: &[u8], set: bool, dict: &mut DictReader<'_>) -> Result<StagedValue> {
if bytes.len() > keys::MAX_VALUE_BYTES {
bail_coded!(ErrorCode::Wal003, bytes.len(), keys::MAX_VALUE_BYTES);
}
if let Some(i) = self.new_long.get(bytes) {
return Ok(StagedValue::NewLong(*i, set));
}
if let Some(vref) = dict.find_long_bytes(bytes)? {
return Ok(StagedValue::Ready(long_key(bytes, set, vref)));
}
let i = self.new_values.len();
self.new_values.push(bytes.to_vec());
self.new_long.insert(bytes.to_vec(), i);
Ok(StagedValue::NewLong(i, set))
}
/// Assign ids for `fact`, reading the committed dictionary.
pub fn stage(&mut self, fact: &Fact, dict: &mut DictReader<'_>) -> Result<()> {
let e = self.eid(fact.entity, dict)?;
let a = self.iid(&fact.attribute, dict)?;
let v = self.value(&fact.value, dict)?;
self.tx(fact.tx_count, fact.tx_id, dict)?;
self.staged.push(Staged {
e,
a,
v,
tx_count: fact.tx_count,
vf: fact.valid_from,
vt: fact.valid_to,
asserted: fact.asserted,
});
Ok(())
}
/// Write the new long values to fresh value pages and build every entry.
pub fn finish(
mut self,
alloc: &mut PageAllocator,
backend: &mut dyn StorageBackend,
cache: &PageCache,
) -> Result<Encoded> {
let mut writer = ValueWriter::new();
let mut new_refs = Vec::with_capacity(self.new_values.len());
for bytes in &self.new_values {
let vref = writer.push(bytes, alloc, backend, cache)?;
self.dict.push((
keys::dict_long_value_key(keys::hash64(bytes), vref),
Vec::new(),
));
new_refs.push(vref);
}
writer.flush(alloc, backend, cache)?;
let mut index: [Vec<Entry>; 4] = Default::default();
for st in self.staged {
let v = match st.v {
StagedValue::Ready(v) => v,
StagedValue::NewLong(i, set) => match (new_refs.get(i), self.new_values.get(i)) {
(Some(vref), Some(bytes)) => long_key(bytes, set, *vref),
_ => bail_coded!(ErrorCode::Int049, "staged long value missing"),
},
};
let kf = KeyFact {
e: st.e,
a: st.a,
v,
tx_count: st.tx_count,
vf: st.vf,
vt: st.vt,
asserted: st.asserted,
};
for (tree, idx) in index.iter_mut().zip(Index::ALL) {
if let Some(k) = kf.key(idx) {
tree.push((k, Vec::new()));
}
}
}
for tree in &mut index {
tree.sort_unstable();
tree.dedup();
}
self.dict.sort_unstable();
if self
.dict
.windows(2)
.any(|w| matches!(w, [a, b] if a.0 == b.0))
{
bail_coded!(ErrorCode::Int049, "a DICT key assigned twice");
}
Ok(Encoded {
index,
dict: self.dict,
next_eid: self.next_eid,
next_iid: self.next_iid,
})
}
}
/// True if `key` is a DICT long-value entry (its value ref keeps a value page alive).
#[cfg(test)]
pub fn is_long_value_entry(key: &[u8]) -> bool {
key.first() == Some(&keys::DICT_LONG_VALUE)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::graph::types::VALID_TIME_FOREVER;
use crate::storage::backend::MemoryBackend;
fn fact(e: u128, a: &str, v: Value, tx: u64) -> Fact {
Fact {
entity: Uuid::from_u128(e),
attribute: a.to_string(),
value: v,
tx_id: 1_000 + tx,
tx_count: tx,
valid_from: 5,
valid_to: VALID_TIME_FOREVER,
asserted: true,
}
}
#[test]
fn uuid_batches_match_scalar_and_only_decode_requested_values() {
let mut backend = MemoryBackend::new();
let cache = PageCache::new(0);
let mut entries: Vec<_> = (1..=2500u64)
.map(|e| {
(
keys::dict_eid_key(e),
if e == 1250 {
vec![0]
} else {
Uuid::from_u128(u128::from(e)).as_bytes().to_vec()
},
)
})
.collect();
// A damaged value must only fail when it is actually requested.
entries.push((keys::dict_eid_key(2501), vec![0]));
let mut alloc = PageAllocator::new(Vec::new(), 2, 1);
entries.push((keys::dict_ident_key(":after"), vec![0]));
entries.sort_by(|a, b| a.0.cmp(&b.0));
let root = btree::build_btree(entries, &mut backend, &cache, &mut alloc).unwrap();
let dict = DictReader::new(root, &backend, &cache);
for requested in [
Vec::new(),
(1..=2500).filter(|&e| e != 1250).collect(),
vec![1, 255, 256, 2048, 2500],
] {
let mut actual = Vec::new();
dict.uuids_of(&requested, &mut |e, u| {
actual.push((e, u));
Ok(())
})
.unwrap();
let mut scalar = DictReader::new(root, &backend, &cache);
let expected: Vec<_> = requested
.iter()
.map(|&e| (e, scalar.uuid_of(e).unwrap()))
.collect();
assert!(actual == expected, "same UUIDs in requested order");
}
for requested in [
vec![1250],
vec![2501],
vec![3000],
vec![2, 1],
vec![1, 1],
(0..64).collect(),
(2440..2504).collect(),
(3000..3064).collect(),
] {
let error = dict.uuids_of(&requested, &mut |_, _| Ok(())).unwrap_err();
let code = crate::MinigrafError::from(error).code();
assert_eq!(
code,
if requested.first() == Some(&1) || requested.first() == Some(&2) {
"INT-049"
} else {
"STG-036"
}
);
}
let empty = DictReader::new(0, &backend, &cache);
empty.uuids_of(&[], &mut |_, _| panic!("no ids")).unwrap();
assert_eq!(
crate::MinigrafError::from(empty.uuids_of(&[1], &mut |_, _| Ok(())).unwrap_err())
.code(),
"STG-036"
);
}
#[test]
fn uuid_batches_preserve_partial_callback_errors_and_tree_errors() {
let mut backend = MemoryBackend::new();
let cache = PageCache::new(0);
let entries = (1..=4096u64)
.map(|e| {
(
keys::dict_eid_key(e),
Uuid::from_u128(u128::from(e)).as_bytes().to_vec(),
)
})
.collect();
let mut alloc = PageAllocator::new(Vec::new(), 2, 1);
let root = btree::build_btree(entries, &mut backend, &cache, &mut alloc).unwrap();
let ids: Vec<_> = (1..=128).collect();
let dict = DictReader::new(root, &backend, &cache);
let mut visits = 0;
assert!(
dict.uuids_of(&ids, &mut |_, _| {
visits += 1;
anyhow::bail!("visitor failed")
})
.is_err()
);
assert_eq!(visits, 1);
assert!(dict.uuids.is_empty(), "no speculative memo entries");
let beyond: Vec<_> = (5000..5064).collect();
assert_eq!(
crate::MinigrafError::from(dict.uuids_of(&beyond, &mut |_, _| Ok(())).unwrap_err())
.code(),
"STG-036",
"end of eid tree"
);
let original = backend.read_page(root).unwrap();
for cycle in [false, true] {
let mut page = original.clone();
if cycle {
let offset = crate::storage::node::RIGHTMOST_CHILD_OFFSET;
page[offset..offset + 8].copy_from_slice(&root.to_le_bytes());
} else {
page[0] = crate::storage::page::PAGE_TYPE_VALUE;
}
crate::storage::page::seal(&mut page, root, 1).unwrap();
backend.write_page(root, &page).unwrap();
let dict = DictReader::new(root, &backend, &cache);
let error = dict.uuids_of(&beyond, &mut |_, _| Ok(())).unwrap_err();
assert_eq!(
crate::MinigrafError::from(error).code(),
if cycle { "INT-049" } else { "STG-013" }
);
}
}
/// Encode `facts` on top of the dictionary at `root`, write the new DICT
/// tree, and return `(new_root, encoded)`.
fn checkpoint(
backend: &mut MemoryBackend,
cache: &PageCache,
root: u64,
counters: (u64, u32),
facts: &[Fact],
) -> (u64, Encoded) {
let mut enc = Encoder::new(counters.0, counters.1);
{
let mut dict = DictReader::new(root, &*backend, cache);
for f in facts {
enc.stage(f, &mut dict).unwrap();
}
}
let start = backend.page_count().unwrap().max(2);
let mut alloc = PageAllocator::new(Vec::new(), start, 1);
let encoded = enc.finish(&mut alloc, backend, cache).unwrap();
let mut freed = Vec::new();
let new_root = btree::cow_insert(
root,
encoded.dict.clone(),
backend,
cache,
&mut alloc,
&mut freed,
)
.unwrap();
(new_root, encoded)
}
fn decode_all(
encoded: &Encoded,
root: u64,
backend: &MemoryBackend,
cache: &PageCache,
) -> Vec<Fact> {
let mut dict = DictReader::new(root, backend, cache);
encoded.index[0]
.iter()
.map(|(k, _)| {
dict.fact(&KeyFact::decode(Index::Eavt, k).unwrap())
.unwrap()
})
.collect()
}
fn same_facts(mut a: Vec<Fact>, mut b: Vec<Fact>) -> bool {
let key = |f: &Fact| crate::storage::index::encode_value(&f.value);
a.sort_by(|x, y| {
(x.entity, &x.attribute, key(x), x.tx_count).cmp(&(
y.entity,
&y.attribute,
key(y),
y.tx_count,
))
});
b.sort_by(|x, y| {
(x.entity, &x.attribute, key(x), x.tx_count).cmp(&(
y.entity,
&y.attribute,
key(y),
y.tx_count,
))
});
a == b
}
#[test]
fn facts_round_trip_through_keys_and_dictionary() {
let mut backend = MemoryBackend::new();
let cache = PageCache::new(256);
let long = "L".repeat(200);
let facts = vec![
fact(1, ":name", Value::String("Alice".into()), 1),
fact(1, ":status", Value::Keyword(":active".into()), 1),
fact(1, ":friend", Value::Ref(Uuid::from_u128(2)), 2),
fact(2, ":bio", Value::String(long.clone()), 2),
fact(2, ":score", Value::Float(-0.5), 3),
fact(2, ":n", Value::Integer(-7), 3),
fact(3, ":flag", Value::Boolean(true), 3),
fact(3, ":none", Value::Null, 3),
];
let (root, enc) = checkpoint(&mut backend, &cache, 0, (1, 1), &facts);
assert_eq!(enc.index[3].len(), 1, "one ref fact in VAET");
assert!(same_facts(decode_all(&enc, root, &backend, &cache), facts));
assert_eq!(enc.next_eid, 4, "entities 1, 2, 3 (2 via a ref)");
}
#[test]
fn ids_are_assigned_once_and_shared_between_attribute_and_keyword() {
let mut backend = MemoryBackend::new();
let cache = PageCache::new(256);
let first = vec![
fact(1, ":color", Value::Keyword(":red".into()), 1),
fact(2, ":red", Value::Integer(1), 1),
];
let (root, enc) = checkpoint(&mut backend, &cache, 0, (1, 1), &first);
// Idents :color and :red: two iids, :red shared by attribute and keyword.
assert_eq!(enc.next_iid, 3);
let dict = DictReader::new(root, &backend, &cache);
let red = dict.iid_of(":red").unwrap().unwrap();
let e1 = dict.eid_of(&Uuid::from_u128(1)).unwrap().unwrap();
// A later checkpoint reuses committed ids and continues the counters.
let second = vec![
fact(1, ":red", Value::Keyword(":blue".into()), 2),
fact(9, ":color", Value::Keyword(":red".into()), 2),
];
let (root2, enc2) = checkpoint(
&mut backend,
&cache,
root,
(enc.next_eid, enc.next_iid),
&second,
);
let dict2 = DictReader::new(root2, &backend, &cache);
assert_eq!(
dict2.iid_of(":red").unwrap(),
Some(red),
"iid never changes"
);
assert_eq!(dict2.eid_of(&Uuid::from_u128(1)).unwrap(), Some(e1));
assert_eq!(enc2.next_iid, 4, "only :blue is new");
assert_eq!(enc2.next_eid, enc.next_eid + 1, "only entity 9 is new");
assert!(same_facts(
decode_all(&enc2, root2, &backend, &cache),
second
));
}
#[test]
fn assignment_is_deterministic() {
let facts: Vec<Fact> = (0..300u128)
.map(|i| {
fact(
i * 7919 % 1000,
&format!(":a{}", i % 13),
Value::Integer(1),
u64::try_from(i / 10).unwrap(),
)
})
.collect();
let run = || {
let mut backend = MemoryBackend::new();
let cache = PageCache::new(256);
let (_, enc) = checkpoint(&mut backend, &cache, 0, (1, 1), &facts);
(enc.index, enc.dict)
};
assert!(
run() == run(),
"same facts in the same order give the same keys"
);
}
#[test]
fn long_values_are_deduplicated() {
let mut backend = MemoryBackend::new();
let cache = PageCache::new(256);
let long = "x".repeat(500);
let mut retract = fact(1, ":bio", Value::String(long.clone()), 2);
retract.asserted = false;
let facts = vec![
fact(1, ":bio", Value::String(long.clone()), 1),
retract,
fact(2, ":bio", Value::String(long.clone()), 2),
];
let (root, enc) = checkpoint(&mut backend, &cache, 0, (1, 1), &facts);
let pages_after_first = backend.page_count().unwrap();
let long_entries = enc
.dict
.iter()
.filter(|(k, _)| is_long_value_entry(k))
.count();
assert_eq!(long_entries, 1, "one stored copy within a checkpoint");
// Re-asserting in a later checkpoint writes no value page.
let again = vec![fact(3, ":bio", Value::String(long), 3)];
let mut enc2 = Encoder::new(enc.next_eid, enc.next_iid);
{
let mut dict = DictReader::new(root, &backend, &cache);
enc2.stage(&again[0], &mut dict).unwrap();
}
let mut alloc = PageAllocator::new(Vec::new(), pages_after_first, 2);
let enc2 = enc2.finish(&mut alloc, &mut backend, &cache).unwrap();
assert_eq!(alloc.next_append(), pages_after_first, "no new value page");
assert!(!enc2.dict.iter().any(|(k, _)| is_long_value_entry(k)));
}
fn long_set_value() -> Value {
use crate::graph::types::ValueSet;
Value::Set(
ValueSet::new(vec![
Value::String("s".repeat(80)),
Value::Keyword(":k/a".into()),
Value::Integer(9),
])
.unwrap(),
)
}
#[test]
fn long_sets_are_deduplicated_and_read_back() {
let mut backend = MemoryBackend::new();
let cache = PageCache::new(256);
let facts = vec![
fact(1, ":s", long_set_value(), 1),
fact(2, ":s", long_set_value(), 1),
];
let (root, enc) = checkpoint(&mut backend, &cache, 0, (1, 1), &facts);
let pages_after_first = backend.page_count().unwrap();
let long_entries = enc
.dict
.iter()
.filter(|(k, _)| is_long_value_entry(k))
.count();
assert_eq!(long_entries, 1, "one stored copy within a checkpoint");
let again = vec![fact(3, ":s", long_set_value(), 2)];
let mut enc2 = Encoder::new(enc.next_eid, enc.next_iid);
{
let mut dict = DictReader::new(root, &backend, &cache);
enc2.stage(&again[0], &mut dict).unwrap();
}
let mut alloc = PageAllocator::new(Vec::new(), pages_after_first, 2);
let enc2 = enc2.finish(&mut alloc, &mut backend, &cache).unwrap();
assert_eq!(alloc.next_append(), pages_after_first, "no new value page");