thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-12-15 10:52:30 +00:00
Code Issues Packages Projects Releases Wiki Activity

Better thread pool

Browse Source
This commit is contained in:
Nikolay Degterinsky 2022-12-14 02:12:08 +00:00
parent 540f890291
commit fef57b4e3b
2 changed files with 22 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/Core/Settings.h
View File

@ -155,8 +155,6 @@ static constexpr UInt64 operator""_GiB(unsigned long long value)
\
M(Bool, allow_experimental_parallel_reading_from_replicas, false, "If true, ClickHouse will send a SELECT query to all replicas of a table. It will work for any kind on MergeTree table.", 0) \
\
M(UInt64, system_replicas_fetch_threads, 16, "The maximum number of threads to fetch data for system.replicas table.", 0) \
\
M(Bool, skip_unavailable_shards, false, "If true, ClickHouse silently skips unavailable shards and nodes unresolvable through DNS. Shard is marked as unavailable when none of the replicas can be reached.", 0) \
\
M(UInt64, parallel_distributed_insert_select, 0, "Process distributed INSERT SELECT query in the same cluster on local tables on every shard; if set to 1 - SELECT is executed on each shard; if set to 2 - SELECT and INSERT are executed on each shard", 0) \

25
src/Storages/System/StorageSystemReplicas.cpp
View File

@ -10,6 +10,7 @@
#include <Common/typeid_cast.h>
#include <Databases/IDatabase.h>
#include <Processors/Sources/SourceFromSingleChunk.h>
#include <Common/getNumberOfPhysicalCPUCores.h>
namespace DB
@ -151,30 +152,46 @@ Pipe StorageSystemReplicas::read(
MutableColumns res_columns = storage_snapshot->metadata->getSampleBlock().cloneEmptyColumns();
auto settings = context->getSettingsRef();
size_t thread_pool_size = settings.system_replicas_fetch_threads;
size_t tables_size = col_database->size();
size_t thread_pool_size = std::min(tables_size, static_cast<size_t>(getNumberOfPhysicalCPUCores()));
auto settings = context->getSettingsRef();
if (settings.max_threads != 0)
thread_pool_size = std::min(thread_pool_size, static_cast<size_t>(settings.max_threads));
ThreadPool thread_pool(thread_pool_size);
std::atomic<bool> error_flag = false;
Exception exception;
size_t tables_size = col_database->size();
std::vector<StorageReplicatedMergeTree::Status> statuses(tables_size);
for (size_t i = 0; i < tables_size; ++i)
{
thread_pool.scheduleOrThrowOnError([i, &statuses, &replicated_tables, &col_database, &col_table, &with_zk_fields]
thread_pool.scheduleOrThrowOnError([&, i=i]
{
try
{
dynamic_cast<StorageReplicatedMergeTree &>(
*replicated_tables
[(*col_database)[i].safeGet<const String &>()]
[(*col_table)[i].safeGet<const String &>()]).getStatus(statuses[i], with_zk_fields);
}
catch (...)
{
tryLogCurrentException("system.replicas", "Failed to fetch system.replicas data");
/// We capture one of the exceptions to be thrown later
if (!error_flag.exchange(true))
exception = Exception(getCurrentExceptionCode(), getCurrentExceptionMessage(false));
}
});
}
thread_pool.wait();
if (error_flag)
throw exception;
for (const auto & status: statuses)
{
size_t col_num = 3;