Skip to content

Commit

Permalink
perf(472): Add metric for index seeks and keys scanned (#501)
Browse files Browse the repository at this point in the history 
Closes #472.
  • Loading branch information
@joshua-spacetime
joshua-spacetime authored Oct 30, 2023
1 parent d1cbef2 commit 7623404
Show file tree
Hide file tree
Showing 3 changed files with 112 additions and 5 deletions.
16 changes: 15 additions & 1 deletion crates/core/src/db/datastore/locking_tx_datastore/btree_index.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -62,14 +62,27 @@ impl Iterator for BTreeIndexIter<'_> {
/// [BTreeIndex]
pub struct BTreeIndexRangeIter<'a> {
range_iter: btree_set::Range<'a, IndexKey>,
num_keys_scanned: u64,
}

impl<'a> Iterator for BTreeIndexRangeIter<'a> {
type Item = &'a RowId;

#[tracing::instrument(skip_all)]
fn next(&mut self) -> Option<Self::Item> {
self.range_iter.next().map(|key| &key.row_id)
if let Some(key) = self.range_iter.next() {
self.num_keys_scanned += 1;
Some(&key.row_id)
} else {
None
}
}
}

impl BTreeIndexRangeIter<'_> {
/// Returns the current number of keys the iterator has scanned.
pub fn keys_scanned(&self) -> u64 {
self.num_keys_scanned
}
}

Expand Down Expand Up @@ -161,6 +174,7 @@ impl BTreeIndex {
let end = map(range.end_bound(), DataKey::max_datakey());
BTreeIndexRangeIter {
range_iter: self.idx.range((start, end)),
num_keys_scanned: 0,
}
}

Expand Down
91 changes: 87 additions & 4 deletions crates/core/src/db/datastore/locking_tx_datastore/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1495,11 +1495,13 @@ impl Inner {
// The current transaction has modified this table, and the table is indexed.
let tx_state = self.tx_state.as_ref().unwrap();
Ok(IterByColRange::Index(IndexSeekIterInner {
ctx,
table_id: *table_id,
tx_state,
inserted_rows,
committed_rows: self.committed_state.index_seek(table_id, &cols, &range),
committed_state: &self.committed_state,
num_committed_rows_fetched: 0,
}))
} else {
// Either the current transaction has not modified this table, or the table is not
Expand All @@ -1513,10 +1515,12 @@ impl Inner {
scan_iter: self.iter(ctx, table_id)?,
})),
Some(tx_state) => Ok(IterByColRange::CommittedIndex(CommittedIndexIter {
ctx,
table_id: *table_id,
tx_state,
committed_state: &self.committed_state,
committed_rows,
num_committed_rows_fetched: 0,
})),
},
None => Ok(IterByColRange::Scan(ScanIterByColRange {
Expand Down Expand Up @@ -1689,7 +1693,7 @@ pub struct Iter<'a> {
table_id: TableId,
inner: &'a Inner,
stage: ScanStage<'a>,
committed_rows_fetched: u64,
num_committed_rows_fetched: u64,
}

impl Drop for Iter<'_> {
Expand All @@ -1702,7 +1706,7 @@ impl Drop for Iter<'_> {
self.ctx.reducer_name().unwrap_or_default(),
&self.table_id.into(),
)
.inc_by(self.committed_rows_fetched);
.inc_by(self.num_committed_rows_fetched);
}
}

Expand All @@ -1713,7 +1717,7 @@ impl<'a> Iter<'a> {
table_id,
inner,
stage: ScanStage::Start,
committed_rows_fetched: 0,
num_committed_rows_fetched: 0,
}
}
}
Expand Down Expand Up @@ -1771,7 +1775,7 @@ impl<'a> Iterator for Iter<'a> {
let _span = tracing::debug_span!("ScanStage::Committed").entered();
for (row_id, row) in iter {
// Increment metric for number of committed rows scanned.
self.committed_rows_fetched += 1;
self.num_committed_rows_fetched += 1;
// Check the committed row's state in the current tx.
match self.inner.tx_state.as_ref().map(|tx_state| tx_state.get_row_op(&table_id, row_id)) {
Some(RowState::Committed(_)) => unreachable!("a row cannot be committed in a tx state"),
Expand Down Expand Up @@ -1802,11 +1806,50 @@ impl<'a> Iterator for Iter<'a> {
}

pub struct IndexSeekIterInner<'a> {
ctx: &'a ExecutionContext<'a>,
table_id: TableId,
tx_state: &'a TxState,
committed_state: &'a CommittedState,
inserted_rows: BTreeIndexRangeIter<'a>,
committed_rows: Option<BTreeIndexRangeIter<'a>>,
num_committed_rows_fetched: u64,
}

impl Drop for IndexSeekIterInner<'_> {
fn drop(&mut self) {
// Increment number of index seeks
DB_METRICS
.rdb_num_index_seeks
.with_label_values(
&self.ctx.txn_type(),
&self.ctx.database(),
self.ctx.reducer_name().unwrap_or_default(),
&self.table_id.0,
)
.inc();

// Increment number of index keys scanned
DB_METRICS
.rdb_num_keys_scanned
.with_label_values(
&self.ctx.txn_type(),
&self.ctx.database(),
self.ctx.reducer_name().unwrap_or_default(),
&self.table_id.0,
)
.inc_by(self.committed_rows.as_ref().map_or(0, |iter| iter.keys_scanned()));

// Increment number of rows fetched
DB_METRICS
.rdb_num_rows_fetched
.with_label_values(
&self.ctx.txn_type(),
&self.ctx.database(),
self.ctx.reducer_name().unwrap_or_default(),
&self.table_id.0,
)
.inc_by(self.num_committed_rows_fetched);
}
}

impl<'a> Iterator for IndexSeekIterInner<'a> {
Expand All @@ -1830,6 +1873,7 @@ impl<'a> Iterator for IndexSeekIterInner<'a> {
.map_or(false, |table| table.contains(row_id))
})
}) {
self.num_committed_rows_fetched += 1;
return Some(get_committed_row(self.committed_state, &self.table_id, row_id));
}

Expand All @@ -1838,10 +1882,48 @@ impl<'a> Iterator for IndexSeekIterInner<'a> {
}

pub struct CommittedIndexIter<'a> {
ctx: &'a ExecutionContext<'a>,
table_id: TableId,
tx_state: &'a TxState,
committed_state: &'a CommittedState,
committed_rows: BTreeIndexRangeIter<'a>,
num_committed_rows_fetched: u64,
}

impl Drop for CommittedIndexIter<'_> {
fn drop(&mut self) {
DB_METRICS
.rdb_num_index_seeks
.with_label_values(
&self.ctx.txn_type(),
&self.ctx.database(),
self.ctx.reducer_name().unwrap_or_default(),
&self.table_id.0,
)
.inc();

// Increment number of index keys scanned
DB_METRICS
.rdb_num_keys_scanned
.with_label_values(
&self.ctx.txn_type(),
&self.ctx.database(),
self.ctx.reducer_name().unwrap_or_default(),
&self.table_id.0,
)
.inc_by(self.committed_rows.keys_scanned());

// Increment number of rows fetched
DB_METRICS
.rdb_num_rows_fetched
.with_label_values(
&self.ctx.txn_type(),
&self.ctx.database(),
self.ctx.reducer_name().unwrap_or_default(),
&self.table_id.0,
)
.inc_by(self.num_committed_rows_fetched);
}
}

impl<'a> Iterator for CommittedIndexIter<'a> {
Expand All @@ -1856,6 +1938,7 @@ impl<'a> Iterator for CommittedIndexIter<'a> {
.get(&self.table_id)
.map_or(false, |table| table.contains(row_id))
}) {
self.num_committed_rows_fetched += 1;
return Some(get_committed_row(self.committed_state, &self.table_id, row_id));
}

Expand Down
10 changes: 10 additions & 0 deletions crates/core/src/db/db_metrics/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -71,6 +71,16 @@ metrics_group!(
#[labels(txn_type: TransactionType, db: Address, reducer: str, table_id: u32)]
pub rdb_num_rows_fetched: IntCounterVec,

#[name = spacetime_num_index_keys_scanned_cumulative]
#[help = "The cumulative number of keys scanned from an index"]
#[labels(txn_type: TransactionType, db: Address, reducer: str, table_id: u32)]
pub rdb_num_keys_scanned: IntCounterVec,

#[name = spacetime_num_index_seeks_cumulative]
#[help = "The cumulative number of index seeks"]
#[labels(txn_type: TransactionType, db: Address, reducer: str, table_id: u32)]
pub rdb_num_index_seeks: IntCounterVec,

#[name = spacetime_num_txns_committed_cumulative]
#[help = "The cumulative number of committed transactions"]
#[labels(txn_type: TransactionType, db: Address, reducer: str)]
Expand Down

1 comment on commit 7623404

@github-actions
Copy link

@github-actions github-actions bot commented on 7623404 Oct 30, 2023 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Benchmarking failed. Please check the workflow run for details.

Please sign in to comment.