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log(schemeshard): add split/merge reason to FLAT_TX_SCHEMESHARD logs #15887

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Merged
merged 1 commit into from
Mar 18, 2025
Merged

log(schemeshard): add split/merge reason to FLAT_TX_SCHEMESHARD logs #15887

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12 changes: 9 additions & 3 deletions ydb/core/tx/schemeshard/schemeshard__table_stats.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -423,8 +423,9 @@ bool TTxStoreTableStats::PersistSingleStats(const TPathId& pathId,

const auto forceShardSplitSettings = Self->SplitSettings.GetForceShardSplitSettings();
TVector<TShardIdx> shardsToMerge;
TString mergeReason;
if ((!index || index->State == NKikimrSchemeOp::EIndexStateReady)
&& table->CheckCanMergePartitions(Self->SplitSettings, forceShardSplitSettings, shardIdx, shardsToMerge, mainTableForIndex)
&& table->CheckCanMergePartitions(Self->SplitSettings, forceShardSplitSettings, shardIdx, shardsToMerge, mainTableForIndex, mergeReason)
) {
TTxId txId = Self->GetCachedTxId(ctx);

Expand All @@ -439,6 +440,10 @@ bool TTxStoreTableStats::PersistSingleStats(const TPathId& pathId,

auto request = MergeRequest(Self, txId, Self->ShardInfos[shardIdx].PathId, shardsToMerge);

LOG_INFO_S(ctx, NKikimrServices::FLAT_TX_SCHEMESHARD,
"Propose merge request : " << request->Record.ShortDebugString()
<< ", reason: " << mergeReason);

TMemoryChanges memChanges;
TStorageChanges dbChanges;
TOperationContext context{Self, txc, ctx, MergeOpSideEffects, memChanges, dbChanges};
Expand All @@ -455,12 +460,13 @@ bool TTxStoreTableStats::PersistSingleStats(const TPathId& pathId,
}

bool collectKeySample = false;
if (table->ShouldSplitBySize(dataSize, forceShardSplitSettings)) {
TString reason;
if (table->ShouldSplitBySize(dataSize, forceShardSplitSettings, reason)) {
// We would like to split by size and do this no matter how many partitions there are
} else if (table->GetPartitions().size() >= table->GetMaxPartitionsCount()) {
// We cannot split as there are max partitions already
return true;
} else if (table->CheckSplitByLoad(Self->SplitSettings, shardIdx, dataSize, rowCount, mainTableForIndex)) {
} else if (table->CheckSplitByLoad(Self->SplitSettings, shardIdx, dataSize, rowCount, mainTableForIndex, reason)) {
collectKeySample = true;
} else {
return true;
Expand Down
9 changes: 7 additions & 2 deletions ydb/core/tx/schemeshard/schemeshard__table_stats_histogram.cpp
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Expand Up @@ -355,11 +355,12 @@ bool TTxPartitionHistogram::Execute(TTransactionContext& txc, const TActorContex
const TTableInfo* mainTableForIndex = Self->GetMainTableForIndex(tableId);

ESplitReason splitReason = ESplitReason::NO_SPLIT;
if (table->ShouldSplitBySize(dataSize, forceShardSplitSettings)) {
TString splitReasonMsg;
if (table->ShouldSplitBySize(dataSize, forceShardSplitSettings, splitReasonMsg)) {
splitReason = ESplitReason::SPLIT_BY_SIZE;
}

if (splitReason == ESplitReason::NO_SPLIT && table->CheckSplitByLoad(Self->SplitSettings, shardIdx, dataSize, rowCount, mainTableForIndex)) {
if (splitReason == ESplitReason::NO_SPLIT && table->CheckSplitByLoad(Self->SplitSettings, shardIdx, dataSize, rowCount, mainTableForIndex, splitReasonMsg)) {
splitReason = ESplitReason::SPLIT_BY_LOAD;
}

Expand Down Expand Up @@ -427,6 +428,10 @@ bool TTxPartitionHistogram::Execute(TTransactionContext& txc, const TActorContex

auto request = SplitRequest(Self, txId, tableId, datashardId, splitKey.GetBuffer());

LOG_INFO_S(ctx, NKikimrServices::FLAT_TX_SCHEMESHARD,
"Propose split request : " << request->Record.ShortDebugString()
<< ", reason: " << splitReasonMsg);

TMemoryChanges memChanges;
TStorageChanges dbChanges;
TOperationContext context{Self, txc, ctx, SplitOpSideEffects, memChanges, dbChanges};
Expand Down
36 changes: 29 additions & 7 deletions ydb/core/tx/schemeshard/schemeshard_info_types.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1873,7 +1873,7 @@ bool TTableInfo::TryAddShardToMerge(const TSplitSettings& splitSettings,
const TForceShardSplitSettings& forceShardSplitSettings,
TShardIdx shardIdx, TVector<TShardIdx>& shardsToMerge,
THashSet<TTabletId>& partOwners, ui64& totalSize, float& totalLoad,
const TTableInfo* mainTableForIndex) const
const TTableInfo* mainTableForIndex, TString& reason) const
{
if (ExpectedPartitionCount + 1 - shardsToMerge.size() <= GetMinPartitionsCount()) {
return false;
Expand Down Expand Up @@ -1904,14 +1904,20 @@ bool TTableInfo::TryAddShardToMerge(const TSplitSettings& splitSettings,
bool canMerge = false;

// Check if we can try merging by size
if (IsMergeBySizeEnabled(forceShardSplitSettings) && stats->DataSize + totalSize <= GetSizeToMerge(forceShardSplitSettings)) {
const auto sizeToMerge = GetSizeToMerge(forceShardSplitSettings);
if (IsMergeBySizeEnabled(forceShardSplitSettings) && stats->DataSize + totalSize <= sizeToMerge) {
reason = TStringBuilder() << "merge by size ("
<< "dataSize: " << stats->DataSize << ", "
<< "totalSize: " << stats->DataSize + totalSize << ", "
<< "sizeToMerge: " << sizeToMerge << ")";
canMerge = true;
}

// Check if we can try merging by load
TInstant now = AppData()->TimeProvider->Now();
TDuration minUptime = TDuration::Seconds(splitSettings.MergeByLoadMinUptimeSec);
if (!canMerge && IsMergeByLoadEnabled(mainTableForIndex) && stats->StartTime && stats->StartTime + minUptime < now) {
reason = "merge by load";
canMerge = true;
}

Expand All @@ -1936,6 +1942,11 @@ bool TTableInfo::TryAddShardToMerge(const TSplitSettings& splitSettings,

if (shardLoad + totalLoad > cpuUsageThreshold *0.7)
return false;

reason = TStringBuilder() << "merge by load ("
<< "shardLoad: " << shardLoad << ", "
<< "totalLoad: " << shardLoad + totalLoad << ", "
<< "loadThreshold: " << cpuUsageThreshold * 0.7 << ")";
}

// Merged shards must not have borrowed parts from the same original tablet
Expand All @@ -1956,7 +1967,7 @@ bool TTableInfo::TryAddShardToMerge(const TSplitSettings& splitSettings,
bool TTableInfo::CheckCanMergePartitions(const TSplitSettings& splitSettings,
const TForceShardSplitSettings& forceShardSplitSettings,
TShardIdx shardIdx, TVector<TShardIdx>& shardsToMerge,
const TTableInfo* mainTableForIndex) const
const TTableInfo* mainTableForIndex, TString& reason) const
{
// Don't split/merge backup tables
if (IsBackup) {
Expand Down Expand Up @@ -1989,20 +2000,21 @@ bool TTableInfo::CheckCanMergePartitions(const TSplitSettings& splitSettings,
THashSet<TTabletId> partOwners;

// Make sure we can actually merge current shard first
if (!TryAddShardToMerge(splitSettings, forceShardSplitSettings, shardIdx, shardsToMerge, partOwners, totalSize, totalLoad, mainTableForIndex)) {
if (!TryAddShardToMerge(splitSettings, forceShardSplitSettings, shardIdx, shardsToMerge, partOwners, totalSize, totalLoad, mainTableForIndex, reason)) {
return false;
}

TString mergeReason;
for (i64 pi = partitionIdx - 1; pi >= 0; --pi) {
if (!TryAddShardToMerge(splitSettings, forceShardSplitSettings, GetPartitions()[pi].ShardIdx, shardsToMerge, partOwners, totalSize, totalLoad, mainTableForIndex)) {
if (!TryAddShardToMerge(splitSettings, forceShardSplitSettings, GetPartitions()[pi].ShardIdx, shardsToMerge, partOwners, totalSize, totalLoad, mainTableForIndex, mergeReason)) {
break;
}
}
// make shardsToMerge ordered by partition index
Reverse(shardsToMerge.begin(), shardsToMerge.end());

for (ui64 pi = partitionIdx + 1; pi < GetPartitions().size(); ++pi) {
if (!TryAddShardToMerge(splitSettings, forceShardSplitSettings, GetPartitions()[pi].ShardIdx, shardsToMerge, partOwners, totalSize, totalLoad, mainTableForIndex)) {
if (!TryAddShardToMerge(splitSettings, forceShardSplitSettings, GetPartitions()[pi].ShardIdx, shardsToMerge, partOwners, totalSize, totalLoad, mainTableForIndex, mergeReason)) {
break;
}
}
Expand All @@ -2013,7 +2025,7 @@ bool TTableInfo::CheckCanMergePartitions(const TSplitSettings& splitSettings,
bool TTableInfo::CheckSplitByLoad(
const TSplitSettings& splitSettings, TShardIdx shardIdx,
ui64 dataSize, ui64 rowCount,
const TTableInfo* mainTableForIndex) const
const TTableInfo* mainTableForIndex, TString& reason) const
{
// Don't split/merge backup tables
if (IsBackup)
Expand Down Expand Up @@ -2067,6 +2079,16 @@ bool TTableInfo::CheckSplitByLoad(
return false;
}

reason = TStringBuilder() << "split by load ("
<< "rowCount: " << rowCount << ", "
<< "minRowCount: " << MIN_ROWS_FOR_SPLIT_BY_LOAD << ", "
<< "dataSize: " << dataSize << ", "
<< "minDataSize: " << MIN_SIZE_FOR_SPLIT_BY_LOAD << ", "
<< "shardCount: " << Stats.PartitionStats.size() << ", "
<< "maxShardCount: " << maxShards << ", "
<< "cpuUsage: " << stats.GetCurrentRawCpuUsage() << ", "
<< "cpuUsageThreshold: " << cpuUsageThreshold * 1000000 << ")";

return true;
}

Expand Down
24 changes: 19 additions & 5 deletions ydb/core/tx/schemeshard/schemeshard_info_types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -685,17 +685,17 @@ struct TTableInfo : public TSimpleRefCount<TTableInfo> {
const TForceShardSplitSettings& forceShardSplitSettings,
TShardIdx shardIdx, TVector<TShardIdx>& shardsToMerge,
THashSet<TTabletId>& partOwners, ui64& totalSize, float& totalLoad,
const TTableInfo* mainTableForIndex) const;
const TTableInfo* mainTableForIndex, TString& reason) const;

bool CheckCanMergePartitions(const TSplitSettings& splitSettings,
const TForceShardSplitSettings& forceShardSplitSettings,
TShardIdx shardIdx, TVector<TShardIdx>& shardsToMerge,
const TTableInfo* mainTableForIndex) const;
const TTableInfo* mainTableForIndex, TString& reason) const;

bool CheckSplitByLoad(
const TSplitSettings& splitSettings, TShardIdx shardIdx,
ui64 dataSize, ui64 rowCount,
const TTableInfo* mainTableForIndex) const;
const TTableInfo* mainTableForIndex, TString& reason) const;

bool IsSplitBySizeEnabled(const TForceShardSplitSettings& params) const {
// Respect unspecified SizeToSplit when force shard splits are disabled
Expand Down Expand Up @@ -818,16 +818,30 @@ struct TTableInfo : public TSimpleRefCount<TTableInfo> {
return stats.DataSize >= params.ForceShardSplitDataSize;
}

bool ShouldSplitBySize(ui64 dataSize, const TForceShardSplitSettings& params) const {
bool ShouldSplitBySize(ui64 dataSize, const TForceShardSplitSettings& params, TString& reason) const {
if (!IsSplitBySizeEnabled(params)) {
return false;
}
// When shard is over the maximum size we split even when over max partitions
if (dataSize >= params.ForceShardSplitDataSize && !params.DisableForceShardSplit) {
reason = TStringBuilder() << "force split by size ("
<< "dataSize: " << dataSize << ", "
<< "maxDataSize: " << params.ForceShardSplitDataSize << ")";

return true;
}
// Otherwise we split when we may add one more partition
return Partitions.size() < GetMaxPartitionsCount() && dataSize >= GetShardSizeToSplit(params);
if (Partitions.size() < GetMaxPartitionsCount() && dataSize >= GetShardSizeToSplit(params)) {
reason = TStringBuilder() << "split by size ("
<< "partitionCount: " << Partitions.size() << ", "
<< "maxPartitionCount: " << GetMaxPartitionsCount() << ", "
<< "dataSize: " << dataSize << ", "
<< "maxDataSize: " << GetShardSizeToSplit(params) << ")";

return true;
}

return false;
}

bool NeedRecreateParts() const {
Expand Down
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