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Fallback to local execution in case of cluster(shard) has only one node

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This commit is contained in:
Igor Nikonov 2024-07-16 19:59:16 +00:00
parent 0056db42be
commit 08dc1c8c37
3 changed files with 41 additions and 2 deletions
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39
src/Interpreters/ClusterProxy/executeQuery.cpp
View File

@ -488,12 +488,12 @@ void executeQueryWithParallelReplicas(
shard_num = column->getUInt(0);
}
const auto shard_count = not_optimized_cluster->getShardCount();
ClusterPtr new_cluster = not_optimized_cluster;
/// if got valid shard_num from query initiator, then parallel replicas scope is the specified shard
/// shards are numbered in order of appearance in the cluster config
if (shard_num > 0)
{
const auto shard_count = not_optimized_cluster->getShardCount();
if (shard_num > shard_count)
throw Exception(
ErrorCodes::LOGICAL_ERROR,
@ -702,6 +702,43 @@ void executeQueryWithParallelReplicasCustomKey(
context, query_info.query, storage_id.getDatabaseName(), storage_id.getTableName(), /*table_function_ptr=*/nullptr);
executeQueryWithParallelReplicasCustomKey(query_plan, storage_id, query_info, columns, snapshot, processed_stage, header, context);
}
bool canUseParallelReplicasOnInitiator(const ContextPtr & context)
{
if (!context->canUseParallelReplicasOnInitiator())
return false;
auto cluster = context->getClusterForParallelReplicas();
if (cluster->getShardCount() == 1)
return cluster->getShardsInfo()[0].getAllNodeCount() > 1;
/// parallel replicas with distributed table
auto scalars = context->hasQueryContext() ? context->getQueryContext()->getScalars() : Scalars{};
UInt64 shard_num = 0; /// shard_num is 1-based, so 0 - no shard specified
const auto it = scalars.find("_shard_num");
if (it != scalars.end())
{
const Block & block = it->second;
const auto & column = block.safeGetByPosition(0).column;
shard_num = column->getUInt(0);
}
if (shard_num > 0)
{
const auto shard_count = cluster->getShardCount();
if (shard_num > shard_count)
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"Shard number is greater than shard count: shard_num={} shard_count={} cluster={}",
shard_num,
shard_count,
cluster->getName());
return cluster->getShardsInfo().at(shard_num - 1).getAllNodeCount() > 1;
}
return false;
}
}
}

2
src/Interpreters/ClusterProxy/executeQuery.h
View File

@ -58,6 +58,8 @@ using AdditionalShardFilterGenerator = std::function<ASTPtr(uint64_t)>;
AdditionalShardFilterGenerator
getShardFilterGeneratorForCustomKey(const Cluster & cluster, ContextPtr context, const ColumnsDescription & columns);
bool canUseParallelReplicasOnInitiator(const ContextPtr & context);
/// Execute a distributed query, creating a query plan, from which the query pipeline can be built.
/// `stream_factory` object encapsulates the logic of creating plans for a different type of query
/// (currently SELECT, DESCRIBE).

2
src/Planner/PlannerJoinTree.cpp
View File

@ -920,7 +920,7 @@ JoinTreeQueryPlan buildQueryPlanForTableExpression(QueryTreeNodePtr table_expres
query_plan = std::move(query_plan_parallel_replicas);
}
}
else if (query_context->canUseParallelReplicasOnInitiator())
else if (ClusterProxy::canUseParallelReplicasOnInitiator(query_context))
{
// (1) find read step
QueryPlan::Node * node = query_plan.getRootNode();