refactor(mito): tidy memtable stats (#4982)

* wip: share same WriteMetrics struct between different memtable implementations

* refactor: extract function to update memtable timestamp range

src/mito2/src/memtable.rs

@@ -42,6 +42,7 @@ use crate::sst::file::FileTimeRange;
 pub mod bulk;
 pub mod key_values;
 pub mod partition_tree;
+mod stats;
 pub mod time_partition;
 pub mod time_series;
 pub(crate) mod version;

src/mito2/src/memtable/partition_tree.rs

@@ -18,7 +18,6 @@ pub(crate) mod data;
 mod dedup;
 mod dict;
 mod merger;
-mod metrics;
 mod partition;
 mod shard;
 mod shard_builder;
@@ -38,8 +37,8 @@ use table::predicate::Predicate;
 use crate::error::{Result, UnsupportedOperationSnafu};
 use crate::flush::WriteBufferManagerRef;
 use crate::memtable::key_values::KeyValue;
-use crate::memtable::partition_tree::metrics::WriteMetrics;
 use crate::memtable::partition_tree::tree::PartitionTree;
+use crate::memtable::stats::WriteMetrics;
 use crate::memtable::{
     AllocTracker, BoxedBatchIterator, BulkPart, IterBuilder, KeyValues, Memtable, MemtableBuilder,
     MemtableId, MemtableRange, MemtableRangeContext, MemtableRef, MemtableStats,
@@ -273,46 +272,7 @@ impl PartitionTreeMemtable {
     fn update_stats(&self, metrics: &WriteMetrics) {
         // Only let the tracker tracks value bytes.
         self.alloc_tracker.on_allocation(metrics.value_bytes);
-
-        loop {
-            let current_min = self.min_timestamp.load(Ordering::Relaxed);
-            if metrics.min_ts >= current_min {
-                break;
-            }
-
-            let Err(updated) = self.min_timestamp.compare_exchange(
-                current_min,
-                metrics.min_ts,
-                Ordering::Relaxed,
-                Ordering::Relaxed,
-            ) else {
-                break;
-            };
-
-            if updated == metrics.min_ts {
-                break;
-            }
-        }
-
-        loop {
-            let current_max = self.max_timestamp.load(Ordering::Relaxed);
-            if metrics.max_ts <= current_max {
-                break;
-            }
-
-            let Err(updated) = self.max_timestamp.compare_exchange(
-                current_max,
-                metrics.max_ts,
-                Ordering::Relaxed,
-                Ordering::Relaxed,
-            ) else {
-                break;
-            };
-
-            if updated == metrics.max_ts {
-                break;
-            }
-        }
+        metrics.update_timestamp_range(&self.max_timestamp, &self.min_timestamp);
     }
 }
 

src/mito2/src/memtable/partition_tree/dict.rs

@@ -19,8 +19,8 @@ use std::sync::Arc;
 
 use datatypes::arrow::array::{Array, ArrayBuilder, BinaryArray, BinaryBuilder};
 
-use crate::memtable::partition_tree::metrics::WriteMetrics;
 use crate::memtable::partition_tree::PkIndex;
+use crate::memtable::stats::WriteMetrics;
 use crate::metrics::MEMTABLE_DICT_BYTES;
 
 /// Maximum keys in a [DictBlock].

src/mito2/src/memtable/partition_tree/metrics.rs

@@ -1,38 +0,0 @@
-// Copyright 2023 Greptime Team
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! Internal metrics of the memtable.
-
-/// Metrics of writing the partition tree.
-pub struct WriteMetrics {
-    /// Size allocated by keys.
-    pub key_bytes: usize,
-    /// Size allocated by values.
-    pub value_bytes: usize,
-    /// Minimum timestamp.
-    pub min_ts: i64,
-    /// Maximum timestamp
-    pub max_ts: i64,
-}
-
-impl Default for WriteMetrics {
-    fn default() -> Self {
-        Self {
-            key_bytes: 0,
-            value_bytes: 0,
-            min_ts: i64::MAX,
-            max_ts: i64::MIN,
-        }
-    }
-}

src/mito2/src/memtable/partition_tree/partition.rs

@@ -30,12 +30,12 @@ use crate::error::Result;
 use crate::memtable::key_values::KeyValue;
 use crate::memtable::partition_tree::data::{DataBatch, DataParts, DATA_INIT_CAP};
 use crate::memtable::partition_tree::dedup::DedupReader;
-use crate::memtable::partition_tree::metrics::WriteMetrics;
 use crate::memtable::partition_tree::shard::{
     BoxedDataBatchSource, Shard, ShardMerger, ShardNode, ShardSource,
 };
 use crate::memtable::partition_tree::shard_builder::ShardBuilder;
 use crate::memtable::partition_tree::{PartitionTreeConfig, PkId};
+use crate::memtable::stats::WriteMetrics;
 use crate::metrics::PARTITION_TREE_READ_STAGE_ELAPSED;
 use crate::read::{Batch, BatchBuilder};
 use crate::row_converter::{McmpRowCodec, RowCodec};

src/mito2/src/memtable/partition_tree/shard.rs

@@ -428,8 +428,8 @@ mod tests {
     use super::*;
     use crate::memtable::partition_tree::data::timestamp_array_to_i64_slice;
     use crate::memtable::partition_tree::dict::KeyDictBuilder;
-    use crate::memtable::partition_tree::metrics::WriteMetrics;
     use crate::memtable::partition_tree::PkIndex;
+    use crate::memtable::stats::WriteMetrics;
     use crate::memtable::KeyValues;
     use crate::test_util::memtable_util::{
         build_key_values_with_ts_seq_values, encode_keys, metadata_for_test,

src/mito2/src/memtable/partition_tree/shard_builder.rs

@@ -26,10 +26,10 @@ use crate::memtable::partition_tree::data::{
     DataBatch, DataBuffer, DataBufferReader, DataBufferReaderBuilder, DataParts, DATA_INIT_CAP,
 };
 use crate::memtable::partition_tree::dict::{DictBuilderReader, KeyDictBuilder};
-use crate::memtable::partition_tree::metrics::WriteMetrics;
 use crate::memtable::partition_tree::partition::PrimaryKeyFilter;
 use crate::memtable::partition_tree::shard::Shard;
 use crate::memtable::partition_tree::{PartitionTreeConfig, PkId, PkIndex, ShardId};
+use crate::memtable::stats::WriteMetrics;
 use crate::metrics::PARTITION_TREE_READ_STAGE_ELAPSED;
 
 /// Builder to write keys and data to a shard that the key dictionary
@@ -318,7 +318,6 @@ mod tests {
 
     use super::*;
     use crate::memtable::partition_tree::data::timestamp_array_to_i64_slice;
-    use crate::memtable::partition_tree::metrics::WriteMetrics;
     use crate::memtable::KeyValues;
     use crate::test_util::memtable_util::{
         build_key_values_with_ts_seq_values, encode_key_by_kv, metadata_for_test,

src/mito2/src/memtable/partition_tree/tree.rs

@@ -33,11 +33,11 @@ use table::predicate::Predicate;
 use crate::error::{PrimaryKeyLengthMismatchSnafu, Result, SerializeFieldSnafu};
 use crate::flush::WriteBufferManagerRef;
 use crate::memtable::key_values::KeyValue;
-use crate::memtable::partition_tree::metrics::WriteMetrics;
 use crate::memtable::partition_tree::partition::{
     Partition, PartitionKey, PartitionReader, PartitionRef, ReadPartitionContext,
 };
 use crate::memtable::partition_tree::PartitionTreeConfig;
+use crate::memtable::stats::WriteMetrics;
 use crate::memtable::{BoxedBatchIterator, KeyValues};
 use crate::metrics::{PARTITION_TREE_READ_STAGE_ELAPSED, READ_ROWS_TOTAL, READ_STAGE_ELAPSED};
 use crate::read::dedup::LastNonNullIter;

src/mito2/src/memtable/stats.rs

@@ -0,0 +1,85 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Internal metrics of the memtable.
+
+use std::sync::atomic::{AtomicI64, Ordering};
+
+/// Metrics of writing memtables.
+pub(crate) struct WriteMetrics {
+    /// Size allocated by keys.
+    pub(crate) key_bytes: usize,
+    /// Size allocated by values.
+    pub(crate) value_bytes: usize,
+    /// Minimum timestamp.
+    pub(crate) min_ts: i64,
+    /// Maximum timestamp
+    pub(crate) max_ts: i64,
+}
+
+impl WriteMetrics {
+    /// Update the min/max timestamp range according to current write metric.
+    pub(crate) fn update_timestamp_range(&self, prev_max_ts: &AtomicI64, prev_min_ts: &AtomicI64) {
+        loop {
+            let current_min = prev_min_ts.load(Ordering::Relaxed);
+            if self.min_ts >= current_min {
+                break;
+            }
+
+            let Err(updated) = prev_min_ts.compare_exchange(
+                current_min,
+                self.min_ts,
+                Ordering::Relaxed,
+                Ordering::Relaxed,
+            ) else {
+                break;
+            };
+
+            if updated == self.min_ts {
+                break;
+            }
+        }
+
+        loop {
+            let current_max = prev_max_ts.load(Ordering::Relaxed);
+            if self.max_ts <= current_max {
+                break;
+            }
+
+            let Err(updated) = prev_max_ts.compare_exchange(
+                current_max,
+                self.max_ts,
+                Ordering::Relaxed,
+                Ordering::Relaxed,
+            ) else {
+                break;
+            };
+
+            if updated == self.max_ts {
+                break;
+            }
+        }
+    }
+}
+
+impl Default for WriteMetrics {
+    fn default() -> Self {
+        Self {
+            key_bytes: 0,
+            value_bytes: 0,
+            min_ts: i64::MAX,
+            max_ts: i64::MIN,
+        }
+    }
+}

src/mito2/src/memtable/time_series.rs

@@ -42,6 +42,7 @@ use crate::error::{
 };
 use crate::flush::WriteBufferManagerRef;
 use crate::memtable::key_values::KeyValue;
+use crate::memtable::stats::WriteMetrics;
 use crate::memtable::{
     AllocTracker, BoxedBatchIterator, BulkPart, IterBuilder, KeyValues, Memtable, MemtableBuilder,
     MemtableId, MemtableRange, MemtableRangeContext, MemtableRef, MemtableStats,
@@ -140,51 +141,13 @@ impl TimeSeriesMemtable {
     }
 
     /// Updates memtable stats.
-    fn update_stats(&self, stats: LocalStats) {
-        self.alloc_tracker.on_allocation(stats.allocated);
-
-        loop {
-            let current_min = self.min_timestamp.load(Ordering::Relaxed);
-            if stats.min_ts >= current_min {
-                break;
-            }
-
-            let Err(updated) = self.min_timestamp.compare_exchange(
-                current_min,
-                stats.min_ts,
-                Ordering::Relaxed,
-                Ordering::Relaxed,
-            ) else {
-                break;
-            };
-
-            if updated == stats.min_ts {
-                break;
-            }
-        }
-
-        loop {
-            let current_max = self.max_timestamp.load(Ordering::Relaxed);
-            if stats.max_ts <= current_max {
-                break;
-            }
-
-            let Err(updated) = self.max_timestamp.compare_exchange(
-                current_max,
-                stats.max_ts,
-                Ordering::Relaxed,
-                Ordering::Relaxed,
-            ) else {
-                break;
-            };
-
-            if updated == stats.max_ts {
-                break;
-            }
-        }
+    fn update_stats(&self, stats: WriteMetrics) {
+        self.alloc_tracker
+            .on_allocation(stats.key_bytes + stats.value_bytes);
+        stats.update_timestamp_range(&self.max_timestamp, &self.min_timestamp);
     }
 
-    fn write_key_value(&self, kv: KeyValue, stats: &mut LocalStats) -> Result<()> {
+    fn write_key_value(&self, kv: KeyValue, stats: &mut WriteMetrics) -> Result<()> {
         ensure!(
             kv.num_primary_keys() == self.row_codec.num_fields(),
             PrimaryKeyLengthMismatchSnafu {
@@ -195,9 +158,9 @@ impl TimeSeriesMemtable {
         let primary_key_encoded = self.row_codec.encode(kv.primary_keys())?;
         let fields = kv.fields().collect::<Vec<_>>();
 
-        stats.allocated += fields.iter().map(|v| v.data_size()).sum::<usize>();
+        stats.value_bytes += fields.iter().map(|v| v.data_size()).sum::<usize>();
         let (series, series_allocated) = self.series_set.get_or_add_series(primary_key_encoded);
-        stats.allocated += series_allocated;
+        stats.key_bytes += series_allocated;
 
         // safety: timestamp of kv must be both present and a valid timestamp value.
         let ts = kv.timestamp().as_timestamp().unwrap().unwrap().value();
@@ -223,13 +186,13 @@ impl Memtable for TimeSeriesMemtable {
     }
 
     fn write(&self, kvs: &KeyValues) -> Result<()> {
-        let mut local_stats = LocalStats::default();
+        let mut local_stats = WriteMetrics::default();
 
         for kv in kvs.iter() {
             self.write_key_value(kv, &mut local_stats)?;
         }
-        local_stats.allocated += kvs.num_rows() * std::mem::size_of::<Timestamp>();
-        local_stats.allocated += kvs.num_rows() * std::mem::size_of::<OpType>();
+        local_stats.value_bytes += kvs.num_rows() * std::mem::size_of::<Timestamp>();
+        local_stats.value_bytes += kvs.num_rows() * std::mem::size_of::<OpType>();
 
         // TODO(hl): this maybe inaccurate since for-iteration may return early.
         // We may lift the primary key length check out of Memtable::write
@@ -241,11 +204,11 @@ impl Memtable for TimeSeriesMemtable {
     }
 
     fn write_one(&self, key_value: KeyValue) -> Result<()> {
-        let mut local_stats = LocalStats::default();
-        let res = self.write_key_value(key_value, &mut local_stats);
-        local_stats.allocated += std::mem::size_of::<Timestamp>() + std::mem::size_of::<OpType>();
+        let mut metrics = WriteMetrics::default();
+        let res = self.write_key_value(key_value, &mut metrics);
+        metrics.value_bytes += std::mem::size_of::<Timestamp>() + std::mem::size_of::<OpType>();
 
-        self.update_stats(local_stats);
+        self.update_stats(metrics);
         self.num_rows.fetch_add(1, Ordering::Relaxed);
         res
     }
@@ -359,22 +322,6 @@ impl Memtable for TimeSeriesMemtable {
     }
 }
 
-struct LocalStats {
-    allocated: usize,
-    min_ts: i64,
-    max_ts: i64,
-}
-
-impl Default for LocalStats {
-    fn default() -> Self {
-        LocalStats {
-            allocated: 0,
-            min_ts: i64::MAX,
-            max_ts: i64::MIN,
-        }
-    }
-}
-
 type SeriesRwLockMap = RwLock<BTreeMap<Vec<u8>, Arc<RwLock<Series>>>>;
 
 #[derive(Clone)]