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Refactor LQ v2 (#3779)

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Przemyslaw Hugh Kaznowski 2024-04-02 10:15:36 +01:00 committed by GitHub
parent 3dc00c8229
commit 09553baae0
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4 changed files with 227 additions and 122 deletions
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10
core/src/cf/mutations.rs
View file

@ -1,3 +1,4 @@
use crate::fflags::FFLAGS;
use crate::sql::array::Array;
use crate::sql::object::Object;
use crate::sql::statements::DefineTableStatement;
@ -21,8 +22,9 @@ pub enum TableMutation {
Del(Thing),
Def(DefineTableStatement),
#[revision(start = 2)]
/// Includes the ID, current value, and changes that were applied to achieve this value
/// Example, ("mytb:tobie", {{"note": "surreal"}}, [{"op": "add", "path": "/note", "value": "surreal"}])
/// Includes the ID, current value (after change), changes that were applied to achieve this
/// value, and if this is a new record (i.e. create = true vs update = false)
/// Example, ("mytb:tobie", {{"note": "surreal"}}, [{"op": "add", "path": "/note", "value": "surreal"}], false)
/// Means that we have already applied the add "/note" operation to achieve the recorded result
SetWithDiff(Thing, Value, Vec<Operation>),
}
@ -77,7 +79,11 @@ impl TableMutation {
let mut h = BTreeMap::<String, Value>::new();
let h = match self {
TableMutation::Set(_thing, v) => {
if FFLAGS.change_feed_live_queries.enabled() {
h.insert("create".to_string(), v);
} else {
h.insert("update".to_string(), v);
}
h
}
TableMutation::SetWithDiff(_thing, current, operations) => {

6
core/src/cf/writer.rs
View file

@ -79,8 +79,14 @@ impl Writer {
match store_difference {
true => {
let patches = current.diff(&previous, Idiom(Vec::new()));
let new_record = !previous.is_some();
trace!("The record is new_record={new_record} because previous is {previous:?}");
if previous.is_none() {
TableMutation::Set(id, current.into_owned())
} else {
TableMutation::SetWithDiff(id, current.into_owned(), patches)
}
}
false => TableMutation::Set(id, current.into_owned()),
},
);

26
core/src/doc/document.rs
View file

@ -37,12 +37,12 @@ impl<'a> CursorDoc<'a> {
ir: Option<IteratorRef>,
rid: Option<&'a Thing>,
doc_id: Option<DocId>,
doc: &'a Value,
doc: Cow<'a, Value>,
) -> Self {
Self {
ir,
rid,
doc: Cow::Borrowed(doc),
doc,
doc_id,
}
}
@ -89,12 +89,32 @@ impl<'a> Document<'a> {
doc_id: Option<DocId>,
val: &'a Value,
extras: Workable,
) -> Self {
Document {
id,
extras,
current: CursorDoc::new(ir, id, doc_id, Cow::Borrowed(val)),
initial: CursorDoc::new(ir, id, doc_id, Cow::Borrowed(val)),
}
}
/// Create a new document that is not going through the standard lifecycle of documents
///
/// This allows for it to be crafted without needing statements to operate on it
#[doc(hidden)]
pub fn new_artificial(
ir: Option<IteratorRef>,
id: Option<&'a Thing>,
doc_id: Option<DocId>,
val: Cow<'a, Value>,
initial: Cow<'a, Value>,
extras: Workable,
) -> Self {
Document {
id,
extras,
current: CursorDoc::new(ir, id, doc_id, val),
initial: CursorDoc::new(ir, id, doc_id, val),
initial: CursorDoc::new(ir, id, doc_id, initial),
}
}
}

209
core/src/kvs/ds.rs
View file

@ -1,3 +1,4 @@
use std::borrow::Cow;
use std::collections::{BTreeMap, BTreeSet};
#[cfg(any(
feature = "kv-surrealkv",
@ -102,7 +103,7 @@ pub struct Datastore {
local_live_queries: Arc<RwLock<BTreeMap<LqIndexKey, Vec<LqIndexValue>>>>,
// Set of tracked change feeds with associated watermarks
// This is updated with new/removed live queries and improves cf request performance
cf_watermarks: Arc<RwLock<BTreeMap<LqSelector, Versionstamp>>>,
cf_watermarks: Arc<Mutex<BTreeMap<LqSelector, Versionstamp>>>,
// Clock for tracking time. It is read only and accessible to all transactions. It is behind a mutex as tests may write to it.
clock: Arc<SizedClock>,
// The index store cache
@ -391,7 +392,7 @@ impl Datastore {
clock,
index_stores: IndexStores::default(),
local_live_queries: Arc::new(RwLock::new(BTreeMap::new())),
cf_watermarks: Arc::new(RwLock::new(BTreeMap::new())),
cf_watermarks: Arc::new(Mutex::new(BTreeMap::new())),
#[cfg(feature = "jwks")]
jwks_cache: Arc::new(RwLock::new(JwksCache::new())),
#[cfg(any(
@ -949,49 +950,21 @@ impl Datastore {
// Change map includes a mapping of selector to changesets, ordered by versionstamp
let mut change_map: BTreeMap<LqSelector, Vec<ChangeSet>> = BTreeMap::new();
let mut tx = self.transaction(Read, Optimistic).await?;
let mut tracked_cfs = self.cf_watermarks.write().await;
let mut tracked_cfs_updates = Vec::with_capacity(tracked_cfs.len());
for (selector, vs) in tracked_cfs.iter() {
// Read the change feed for the selector
let res = cf::read(
&mut tx,
&selector.ns,
&selector.db,
// Technically, we can not fetch by table and do the per-table filtering this side.
// That is an improvement though
Some(&selector.tb),
ShowSince::versionstamp(vs),
Some(self.engine_options.live_query_catchup_size),
{
let tx = self.transaction(Read, Optimistic).await?;
let tracked_cfs_updates = find_required_cfs_to_catch_up(
tx,
self.cf_watermarks.clone(),
self.engine_options.live_query_catchup_size,
&mut change_map,
)
.await?;
// Confirm we do need to change watermark - this is technically already handled by the cf range scan
if res.is_empty() {
trace!(
"There were no changes in the change feed for {:?} from versionstamp {:?}",
selector,
conv::versionstamp_to_u64(vs)
)
}
if let Some(change_set) = res.last() {
if conv::versionstamp_to_u64(&change_set.0) > conv::versionstamp_to_u64(vs) {
trace!("Adding a change set for lq notification processing");
// Update the cf watermark so we can progress scans
// If the notifications fail from here-on, they are lost
// this is a separate vec that we later insert to because we are iterating immutably
// We shouldn't use a read lock because of consistency between watermark scans
tracked_cfs_updates.push((selector.clone(), change_set.0));
// This does not guarantee a notification, as a changeset an include many tables and many changes
change_map.insert(selector.clone(), res);
}
}
}
tx.cancel().await?;
// Now we update since we are no longer iterating immutably
let mut tracked_cfs = self.cf_watermarks.lock().await;
for (selector, vs) in tracked_cfs_updates {
tracked_cfs.insert(selector, vs);
}
};
for (selector, change_sets) in change_map {
// find matching live queries
@ -1009,8 +982,34 @@ impl Datastore {
// Find relevant changes
let tx = Arc::new(Mutex::new(self.transaction(Read, Optimistic).await?));
trace!("There are {} change sets", change_sets.len());
trace!(
"\n{}",
change_sets
.iter()
.enumerate()
.map(|(i, x)| format!("[{i}] {:?}", x))
.collect::<Vec<String>>()
.join("\n")
);
for change_set in change_sets {
self.process_change_set_for_notifications(tx.clone(), opt, change_set, &lq_pairs)
.await?;
}
}
trace!("Finished process lq successfully");
Ok(())
}
async fn process_change_set_for_notifications(
&self,
tx: Arc<Mutex<Transaction>>,
opt: &Options,
change_set: ChangeSet,
lq_pairs: &[(LqIndexKey, LqIndexValue)],
) -> Result<(), Error> {
// TODO(phughk): this loop can be on the inside so we are only checking lqs relavant to cf change
trace!("Moving to next change set, {:?}", change_set);
for (lq_key, lq_value) in lq_pairs.iter() {
trace!(
"Processing live query for notification key={:?} and value={:?}",
@ -1024,14 +1023,24 @@ impl Datastore {
// Create a doc of the table value
// Run the 'lives' logic on the doc, while providing live queries instead of reading from storage
// This will generate and send notifications
for mutation in table_mutations.1.iter() {
trace!(
"There are {} table mutations being prepared for notifications",
table_mutations.1.len()
);
for (i, mutation) in table_mutations.1.iter().enumerate() {
trace!(
"[{} @ {:?}] Processing table mutation: {:?}",
i,
change_vs,
mutation
);
trace!("Constructing document from mutation");
if let Some(doc) = Self::construct_document(mutation) {
// We know we are only processing a single LQ at a time, so we can limit notifications to 1
let notification_capacity = 1;
// We track notifications as a separate channel in case we want to process
// for the current state we only forward
let (sender, receiver) =
channel::bounded(notification_capacity);
let (sender, receiver) = channel::bounded(notification_capacity);
doc.check_lqs_and_send_notifications(
opt,
&Statement::Live(&lq_value.stm),
@ -1062,25 +1071,7 @@ impl Datastore {
trace!("Ended notification sending")
}
// Update watermarks
trace!(
"Updating watermark to {:?} for index key {:?}",
change_vs,
lq_key
);
// For each live query we have processed we update the watermarks
self.local_live_queries.write().await.insert(
(*lq_key).clone(),
vec![LqIndexValue {
vs: change_vs,
..lq_value.clone()
}],
);
// We also update the tracked_cfs with a minimum watermark
}
}
self.update_versionstamp(&change_vs, lq_key, lq_value).await;
}
}
}
@ -1088,21 +1079,57 @@ impl Datastore {
Ok(())
}
async fn update_versionstamp(
&self,
change_vs: &Versionstamp,
lq_key: &LqIndexKey,
lq_value: &LqIndexValue,
) {
// We increase the watermark because scans are inclusive of first result
// And we have already processed the input watermark - it is derived from the event
// let change_vs = conv::try_u128_to_versionstamp(conv::to_u128_be(*change_vs) + 1).unwrap();
// Update watermarks
trace!("Updating watermark to {:?} for index key {:?}", change_vs, lq_key);
// For each live query we have processed we update the watermarks
self.local_live_queries.write().await.insert(
lq_key.clone(),
vec![LqIndexValue {
vs: *change_vs,
..lq_value.clone()
}],
);
// TODO(phugk) We also update the tracked_cfs with a minimum watermark
let mut tracked_cfs = self.cf_watermarks.lock().await;
// TODO we may be able to re-use the key without cloning...
tracked_cfs.insert(lq_key.selector.clone(), *change_vs).unwrap();
}
/// Construct a document from a Change Feed mutation
/// This is required to perform document operations such as live query notifications
fn construct_document(mutation: &TableMutation) -> Option<Document> {
match mutation {
TableMutation::Set(a, b) => {
let doc = Document::new(None, Some(a), None, b, Workable::Normal);
TableMutation::Set(id, current_value) => {
let doc = Document::new(None, Some(id), None, current_value, Workable::Normal);
Some(doc)
}
TableMutation::Del(a) => {
let doc = Document::new(None, Some(a), None, &Value::None, Workable::Normal);
TableMutation::Del(id) => {
let doc = Document::new(None, Some(id), None, &Value::None, Workable::Normal);
Some(doc)
}
TableMutation::Def(_) => None,
TableMutation::SetWithDiff(id, new, _operations) => {
let doc = Document::new(None, Some(id), None, new, Workable::Normal);
TableMutation::SetWithDiff(id, current_value, _operations) => {
let todo_original_after_reverse_applying_patches = Value::None;
let doc = Document::new_artificial(
None,
Some(id),
None,
Cow::Borrowed(current_value),
Cow::Owned(todo_original_after_reverse_applying_patches),
Workable::Normal,
);
trace!("Constructed artificial document: {:?}, is_new={}", doc, doc.is_new());
// TODO(SUR-328): reverse diff and apply to doc to retrieve original version of doc
Some(doc)
}
@ -1117,7 +1144,7 @@ impl Datastore {
) -> Result<(), Error> {
// Lock the local live queries
let mut lq_map = self.local_live_queries.write().await;
let mut cf_watermarks = self.cf_watermarks.write().await;
let mut cf_watermarks = self.cf_watermarks.lock().await;
let mut watermarks_to_check: Vec<LqIndexKey> = vec![];
for lq in lqs {
match lq {
@ -1705,3 +1732,49 @@ impl Datastore {
Ok(())
}
}
async fn find_required_cfs_to_catch_up(
mut tx: Transaction,
tracked_cfs: Arc<Mutex<BTreeMap<LqSelector, Versionstamp>>>,
catchup_size: u32,
change_map: &mut BTreeMap<LqSelector, Vec<ChangeSet>>,
) -> Result<Vec<(LqSelector, Versionstamp)>, Error> {
let tracked_cfs = tracked_cfs.lock().await;
let mut tracked_cfs_updates = Vec::with_capacity(tracked_cfs.len());
for (selector, vs) in tracked_cfs.iter() {
// Read the change feed for the selector
let res = cf::read(
&mut tx,
&selector.ns,
&selector.db,
// Technically, we can not fetch by table and do the per-table filtering this side.
// That is an improvement though
Some(&selector.tb),
ShowSince::versionstamp(vs),
Some(catchup_size),
)
.await?;
// Confirm we do need to change watermark - this is technically already handled by the cf range scan
if res.is_empty() {
trace!(
"There were no changes in the change feed for {:?} from versionstamp {:?}",
selector,
conv::versionstamp_to_u64(vs)
)
}
if let Some(change_set) = res.last() {
if conv::versionstamp_to_u64(&change_set.0) > conv::versionstamp_to_u64(vs) {
trace!("Adding a change set for lq notification processing");
// Update the cf watermark so we can progress scans
// If the notifications fail from here-on, they are lost
// this is a separate vec that we later insert to because we are iterating immutably
// We shouldn't use a read lock because of consistency between watermark scans
tracked_cfs_updates.push((selector.clone(), change_set.0));
// This does not guarantee a notification, as a changeset an include many tables and many changes
change_map.insert(selector.clone(), res);
}
}
}
tx.cancel().await?;
Ok(tracked_cfs_updates)
}