From f2c2026715745a19fffe34e46549d68fc3dfed2d Mon Sep 17 00:00:00 2001
From: Neil Shen <overvenus@gmail.com>
Date: Thu, 16 Mar 2023 15:22:39 +0800
Subject: [PATCH] scheduler(ticdc): log splits (#8543)

ref pingcap/tiflow#7720
---
 .../v3/keyspan/splitter_region_count.go       | 19 +++++++++++++++++++
 .../internal/v3/keyspan/splitter_write.go     | 17 ++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/cdc/scheduler/internal/v3/keyspan/splitter_region_count.go b/cdc/scheduler/internal/v3/keyspan/splitter_region_count.go
index 49678971c1d..86e4d0a3b50 100644
--- a/cdc/scheduler/internal/v3/keyspan/splitter_region_count.go
+++ b/cdc/scheduler/internal/v3/keyspan/splitter_region_count.go
@@ -50,10 +50,18 @@ func (m *regionCountSplitter) split(
 		log.Warn("schedulerv3: list regions failed, skip split span",
 			zap.String("namespace", m.changefeedID.Namespace),
 			zap.String("changefeed", m.changefeedID.ID),
+			zap.String("span", span.String()),
 			zap.Error(err))
 		return []tablepb.Span{span}
 	}
 	if len(regions) <= config.RegionThreshold || totalCaptures == 0 {
+		log.Info("schedulerv3: skip split span by region count",
+			zap.String("namespace", m.changefeedID.Namespace),
+			zap.String("changefeed", m.changefeedID.ID),
+			zap.String("span", span.String()),
+			zap.Int("totalCaptures", totalCaptures),
+			zap.Int("regionCount", len(regions)),
+			zap.Int("regionThreshold", config.RegionThreshold))
 		return []tablepb.Span{span}
 	}
 
@@ -70,6 +78,7 @@ func (m *regionCountSplitter) split(
 			log.Warn("schedulerv3: get regions failed, skip split span",
 				zap.String("namespace", m.changefeedID.Namespace),
 				zap.String("changefeed", m.changefeedID.ID),
+				zap.String("span", span.String()),
 				zap.Error(err))
 			return []tablepb.Span{span}
 		}
@@ -78,6 +87,7 @@ func (m *regionCountSplitter) split(
 			log.Warn("schedulerv3: get regions failed, skip split span",
 				zap.String("namespace", m.changefeedID.Namespace),
 				zap.String("changefeed", m.changefeedID.ID),
+				zap.String("span", span.String()),
 				zap.Error(err))
 			return []tablepb.Span{span}
 		}
@@ -86,6 +96,7 @@ func (m *regionCountSplitter) split(
 			log.Warn("schedulerv3: list region out of order detected",
 				zap.String("namespace", m.changefeedID.Namespace),
 				zap.String("changefeed", m.changefeedID.ID),
+				zap.String("span", span.String()),
 				zap.Stringer("lastSpan", &spans[len(spans)-1]),
 				zap.Stringer("region", startRegion))
 			return []tablepb.Span{span}
@@ -110,6 +121,14 @@ func (m *regionCountSplitter) split(
 	// Make sure spans does not exceed [startKey, endKey).
 	spans[0].StartKey = span.StartKey
 	spans[len(spans)-1].EndKey = span.EndKey
+	log.Info("schedulerv3: split span by region count",
+		zap.String("namespace", m.changefeedID.Namespace),
+		zap.String("changefeed", m.changefeedID.ID),
+		zap.String("span", span.String()),
+		zap.Int("spans", len(spans)),
+		zap.Int("totalCaptures", totalCaptures),
+		zap.Int("regionCount", len(regions)),
+		zap.Int("regionThreshold", config.RegionThreshold))
 	return spans
 }
 
diff --git a/cdc/scheduler/internal/v3/keyspan/splitter_write.go b/cdc/scheduler/internal/v3/keyspan/splitter_write.go
index 8f7bc3a9a2d..4ef4d130040 100644
--- a/cdc/scheduler/internal/v3/keyspan/splitter_write.go
+++ b/cdc/scheduler/internal/v3/keyspan/splitter_write.go
@@ -49,16 +49,31 @@ func (m *writeSplitter) split(
 	regions, err := m.pdAPIClient.ScanRegions(ctx, span)
 	if err != nil {
 		// Skip split.
+		log.Warn("schedulerv3: scan regions failed, skip split span",
+			zap.String("namespace", m.changefeedID.Namespace),
+			zap.String("changefeed", m.changefeedID.ID),
+			zap.String("span", span.String()),
+			zap.Error(err))
 		return nil
 	}
 	if totalCaptures <= 1 {
+		log.Warn("schedulerv3: only one capture, skip split span",
+			zap.String("namespace", m.changefeedID.Namespace),
+			zap.String("changefeed", m.changefeedID.ID),
+			zap.String("span", span.String()),
+			zap.Error(err))
 		return []tablepb.Span{span}
 	}
 	info := splitRegionsByWrittenKeys(span.TableID, regions, config.WriteKeyThreshold, totalCaptures)
 	log.Info("schedulerv3: split span by written keys",
+		zap.String("namespace", m.changefeedID.Namespace),
+		zap.String("changefeed", m.changefeedID.ID),
+		zap.String("span", span.String()),
 		zap.Ints("counts", info.Counts),
 		zap.Ints("weights", info.Weights),
-		zap.String("span", span.String()))
+		zap.Int("spans", len(info.Spans)),
+		zap.Int("totalCaptures", totalCaptures),
+		zap.Int("writeKeyThreshold", config.WriteKeyThreshold))
 	return info.Spans
 }