(kvrocks) branch unstable updated: feat(tdigest): refactor buffer merge's min max updating logic (#2814)

[twice]

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twice pushed a commit to branch unstable
in repository https://gitbox.apache.org/repos/asf/kvrocks.git


The following commit(s) were added to refs/heads/unstable by this push:
     new 45037538 feat(tdigest): refactor buffer merge's min max updating logic 
(#2814)
45037538 is described below

commit 45037538ca4a4722e1d4134bcdde57d7f1f815d2
Author: Edward Xu <xuxian...@foxmail.com>
AuthorDate: Wed Mar 5 12:45:47 2025 +0800

    feat(tdigest): refactor buffer merge's min max updating logic (#2814)
---
 src/types/redis_tdigest.cc |  5 +++--
 src/types/tdigest.cc       | 10 ++--------
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/src/types/redis_tdigest.cc b/src/types/redis_tdigest.cc
index 6953f476..0ee55740 100644
--- a/src/types/redis_tdigest.cc
+++ b/src/types/redis_tdigest.cc
@@ -161,6 +161,9 @@ rocksdb::Status TDigest::Add(engine::Context& ctx, const 
Slice& digest_name, con
 
   metadata.total_observations += inputs.size();
   metadata.total_weight += inputs.size();
+  auto [buffer_min, buffer_max] = std::minmax_element(inputs.cbegin(), 
inputs.cend());
+  metadata.maximum = std::max(metadata.maximum, *buffer_max);
+  metadata.minimum = std::min(metadata.minimum, *buffer_min);
 
   if (metadata.unmerged_nodes + inputs.size() <= metadata.capacity) {
     if (auto status = appendBuffer(ctx, batch, ns_key, inputs, &metadata); 
!status.ok()) {
@@ -279,8 +282,6 @@ rocksdb::Status 
TDigest::mergeCurrentBuffer(engine::Context& ctx, const std::str
   metadata->merge_times++;
   metadata->merged_nodes = merged_centroids->centroids.size();
   metadata->unmerged_nodes = 0;
-  metadata->minimum = merged_centroids->min;
-  metadata->maximum = merged_centroids->max;
   metadata->merged_weight = 
static_cast<uint64_t>(merged_centroids->total_weight);
 
   return rocksdb::Status::OK();
diff --git a/src/types/tdigest.cc b/src/types/tdigest.cc
index 43a5a798..a51967a4 100644
--- a/src/types/tdigest.cc
+++ b/src/types/tdigest.cc
@@ -119,8 +119,8 @@ class TDigestImpl {
     tdigests_[1].resize(0);
     current_ = 0;
     total_weight_ = 0;
-    min_ = std::numeric_limits<double>::infinity();
-    max_ = -std::numeric_limits<double>::infinity();
+    min_ = std::numeric_limits<double>::max();
+    max_ = std::numeric_limits<double>::lowest();
     merger_.Reset(0, nullptr);
   }
 
@@ -225,18 +225,12 @@ class TDigestImpl {
 
   // merge input data with current tdigest
   void MergeInput(std::vector<double> input) {
-    if (tdigests_[current_].empty() && !input.empty()) {
-      min_ = input.front();
-      max_ = input.front();
-    }
     total_weight_ += static_cast<double>(input.size());
 
     std::sort(input.begin(), input.end());
     if (input.empty()) {
       return;
     }
-    min_ = std::min(min_, input.front());
-    max_ = std::max(max_, input.back());
 
     // pick next minimal centroid from input and tdigest, feed to merger
     merger_.Reset(total_weight_, &tdigests_[1 - current_]);