YT-19324: move YT provider to ydb/library/yql

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This commit has zero effect on all projects that depend on YQL.

The summary of changes:
- `yql/providers/yt -> ydb/library/yql/providers/yt `- the whole implementation of YT provider is moved into YDB code base for further export as a part of YT YQL plugin shared library;
- `yql/providers/stat/{expr_nodes,uploader} -> ydb/library/yql/providers/stat/{expr_nodes,uploader}` - a small interface without implementation and the description of stat expr nodes;
- `yql/core/extract_predicate/ut -> ydb/library/yql/core/extract_predicate/ut`;
- `yql/core/{ut,ut_common} -> ydb/library/yql/core/{ut,ut_common}`;
- `yql/core` is gone;
- `yql/library/url_preprocessing -> ydb/library/yql/core/url_preprocessing`.

**NB**: all new targets inside `ydb/` are under `IF (NOT CMAKE_EXPORT)` clause which disables them from open-source cmake generation and ya make build. They will be enabled in the subsequent commits.

1 files changed, 65 insertions, 0 deletions

diff --git a/yt/yt/client/hedging/hedging.h b/yt/yt/client/hedging/hedging.h
new file mode 100644
index 0000000000..3c515ce8b9
--- /dev/null
+++ b/yt/yt/client/hedging/hedging.h
@@ -0,0 +1,65 @@
+#pragma once
+
+#include "public.h"
+
+#include "hedging_executor.h"
+#include "penalty_provider.h"
+
+#include <yt/yt/client/api/client.h>
+
+// @brief   HedgingClient is a wrapper for several YT-clients with ability
+//          to retry asynchronously the same request with different underlying-clients.
+//          HedgingClient implements IClient interface and supports methods that do not change state of data on YT.
+//          Currently supported methods: LookupRows, VersionedLookupRows, SelectRows, ExplainQuery,
+//          CreateTableReader, GetNode, ListNode, NodeExists, CreateFileReader
+//
+//          For initial configuration every YT-client needs an InitialPenalty value.
+//          This value is used to determine in which order YT-clients will be used.
+//
+//          MinInitialPenalty - minimal retry timeout value out of all YT-clients.
+//          EffectivePenalty - is a delay value for starting a request with a corresponding YT-client.
+//          For every client this value is calculated as: InitialPenalty - MinInitialPenalty.
+//
+//          If any of the clients responses with a success result: requests to other YT-clients are cancelled.
+//
+//          If any of the clients responses with an error: it's InitialPenalty is
+//          increased by BanPenalty value for the next BanDuration time interval.
+//          Both BanPenalty and BanDuration values are set in MultiClientCluster config.
+namespace NYT::NClient::NHedging::NRpc {
+
+////////////////////////////////////////////////////////////////////////////////
+
+// from config.proto
+class THedgingClientConfig;
+
+// @brief Options for hedging client.
+//        from hedging_executor.h
+struct THedgingClientOptions;
+
+////////////////////////////////////////////////////////////////////////////////
+
+// @brief Method for creating HedgingClient with given options.
+NApi::IClientPtr CreateHedgingClient(const THedgingClientOptions& options);
+
+// @brief Method for creating HedgingClient with given options and ability to use penalty updater policy.
+//        Currently for experimental usage.
+NApi::IClientPtr CreateHedgingClient(const THedgingClientOptions& options, const IPenaltyProviderPtr& penaltyProvider);
+
+// @brief Method for creating HedgingClient with given rpc clients config.
+NApi::IClientPtr CreateHedgingClient(const THedgingClientConfig& config);
+
+// @brief Method for creating HedgingClient with given rpc clients config and preinitialized clients.
+NApi::IClientPtr CreateHedgingClient(const THedgingClientConfig& config, const IClientsCachePtr& clientsCache);
+
+// @brief Method for creating HedgingClient with given rpc clients config, preinitialized clients and PenaltyProvider.
+NApi::IClientPtr CreateHedgingClient(const THedgingClientConfig& config, const IClientsCachePtr& clientsCache, const IPenaltyProviderPtr& penaltyProvider);
+
+// @brief Method for creating HedgingClient options from given config and preinitialized clients.
+THedgingClientOptions GetHedgingClientOptions(const THedgingClientConfig& config, const IClientsCachePtr& clientsCache);
+
+// @brief Method for creating HedgingClient options from given config.
+THedgingClientOptions GetHedgingClientOptions(const THedgingClientConfig& config);
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NClient::NHedging::NRpc