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feat: avoid populating the high part of append-only group topn cache (#23264) #23266

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feat: avoid populating the high part of append-only group topn cache (#23264) #23266

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2 changes: 1 addition & 1 deletion src/stream/src/executor/top_n/group_top_n_appendonly.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,7 @@ where
self.metrics.group_top_n_cache_miss_count.inc();
let mut topn_cache = TopNCache::new(self.offset, self.limit, data_types.clone());
self.managed_state
.init_topn_cache(Some(group_key), &mut topn_cache)
.init_append_only_topn_cache(Some(group_key), &mut topn_cache)
.await?;
self.caches.put(group_cache_key.clone(), topn_cache);
}
Expand Down
78 changes: 50 additions & 28 deletions src/stream/src/executor/top_n/top_n_state.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -198,10 +198,11 @@ impl<S: StateStore> ManagedTopNState<S> {
Ok(())
}

pub async fn init_topn_cache<const WITH_TIES: bool>(
pub async fn init_topn_cache_inner<const WITH_TIES: bool>(
&self,
group_key: Option<impl GroupKey>,
topn_cache: &mut TopNCache<WITH_TIES>,
skip_high: bool,
) -> StreamExecutorResult<()> {
assert!(topn_cache.low.as_ref().map(Cache::is_empty).unwrap_or(true));
assert!(topn_cache.middle.is_empty());
Expand Down Expand Up @@ -263,43 +264,64 @@ impl<S: StateStore> ManagedTopNState<S> {
}
}

assert!(
topn_cache.high_cache_capacity > 0,
"topn cache high_capacity should always > 0"
);
while !topn_cache.high_is_full()
&& let Some(item) = state_table_iter.next().await
{
group_row_count += 1;
let topn_row = self.get_topn_row(item?.into_owned_row(), group_key.len());
topn_cache
.high
.insert(topn_row.cache_key, (&topn_row.row).into());
}
if WITH_TIES && topn_cache.high_is_full() {
let high_last_sort_key = topn_cache.high.last_key_value().unwrap().0.0.clone();
while let Some(item) = state_table_iter.next().await {
if !skip_high {
assert!(
topn_cache.high_cache_capacity > 0,
"topn cache high_capacity should always > 0"
);
while !topn_cache.high_is_full()
&& let Some(item) = state_table_iter.next().await
{
group_row_count += 1;
let topn_row = self.get_topn_row(item?.into_owned_row(), group_key.len());
if topn_row.cache_key.0 == high_last_sort_key {
topn_cache
.high
.insert(topn_row.cache_key, (&topn_row.row).into());
} else {
break;
topn_cache
.high
.insert(topn_row.cache_key, (&topn_row.row).into());
}
if WITH_TIES && topn_cache.high_is_full() {
let high_last_sort_key = topn_cache.high.last_key_value().unwrap().0.0.clone();
while let Some(item) = state_table_iter.next().await {
group_row_count += 1;
let topn_row = self.get_topn_row(item?.into_owned_row(), group_key.len());
if topn_row.cache_key.0 == high_last_sort_key {
topn_cache
.high
.insert(topn_row.cache_key, (&topn_row.row).into());
} else {
break;
}
}
}
}

if state_table_iter.next().await.is_none() {
// After trying to initially fill in the cache, all table entries are in the cache,
// we then get the precise table row count.
if state_table_iter.next().await.is_none() {
// After trying to initially fill in the cache, all table entries are in the cache,
// we then get the precise table row count.
topn_cache.update_table_row_count(group_row_count);
}
} else {
topn_cache.update_table_row_count(group_row_count);
}

Ok(())
}

pub async fn init_topn_cache<const WITH_TIES: bool>(
&self,
group_key: Option<impl GroupKey>,
topn_cache: &mut TopNCache<WITH_TIES>,
) -> StreamExecutorResult<()> {
self.init_topn_cache_inner(group_key, topn_cache, false)
.await
}

pub async fn init_append_only_topn_cache<const WITH_TIES: bool>(
&self,
group_key: Option<impl GroupKey>,
topn_cache: &mut TopNCache<WITH_TIES>,
) -> StreamExecutorResult<()> {
self.init_topn_cache_inner(group_key, topn_cache, true)
.await
}

pub async fn flush(
&mut self,
epoch: EpochPair,
Expand Down