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#include <Functions/FunctionConstantBase.h>
#include <DataTypes/DataTypeNothing.h>
#include <DataTypes/DataTypesNumber.h>
#include <Functions/FunctionFactory.h>
#include <Interpreters/Context.h>
#include <Interpreters/MergeTreeTransaction.h>
#include <Interpreters/TransactionLog.h>
namespace DB
{
namespace
{
class FunctionTransactionID : public FunctionConstantBase<FunctionTransactionID, Tuple, DataTypeNothing>
{
public:
static constexpr auto name = "transactionID";
static Tuple getValue(const MergeTreeTransactionPtr & txn)
{
Tuple res;
if (txn)
res = {txn->tid.start_csn, txn->tid.local_tid, txn->tid.host_id};
else
res = {static_cast<UInt64>(0), static_cast<UInt64>(0), UUIDHelpers::Nil};
return res;
}
DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override { return getTransactionIDDataType(); }
static FunctionPtr create(ContextPtr context) { return std::make_shared<FunctionTransactionID>(context); }
explicit FunctionTransactionID(ContextPtr context) : FunctionConstantBase(getValue(context->getCurrentTransaction()), context->isDistributed()) {}
};
class FunctionTransactionLatestSnapshot : public FunctionConstantBase<FunctionTransactionLatestSnapshot, UInt64, DataTypeUInt64>
{
static UInt64 getLatestSnapshot(ContextPtr context)
{
context->checkTransactionsAreAllowed(/* explicit_tcl_query */ true);
return TransactionLog::instance().getLatestSnapshot();
}
public:
static constexpr auto name = "transactionLatestSnapshot";
static FunctionPtr create(ContextPtr context) { return std::make_shared<FunctionTransactionLatestSnapshot>(context); }
explicit FunctionTransactionLatestSnapshot(ContextPtr context) : FunctionConstantBase(getLatestSnapshot(context), context->isDistributed()) {}
};
class FunctionTransactionOldestSnapshot : public FunctionConstantBase<FunctionTransactionOldestSnapshot, UInt64, DataTypeUInt64>
{
static UInt64 getOldestSnapshot(ContextPtr context)
{
context->checkTransactionsAreAllowed(/* explicit_tcl_query */ true);
return TransactionLog::instance().getOldestSnapshot();
}
public:
static constexpr auto name = "transactionOldestSnapshot";
static FunctionPtr create(ContextPtr context) { return std::make_shared<FunctionTransactionOldestSnapshot>(context); }
explicit FunctionTransactionOldestSnapshot(ContextPtr context) : FunctionConstantBase(getOldestSnapshot(context), context->isDistributed()) {}
};
}
REGISTER_FUNCTION(TransactionCounters)
{
factory.registerFunction<FunctionTransactionID>();
factory.registerFunction<FunctionTransactionLatestSnapshot>();
factory.registerFunction<FunctionTransactionOldestSnapshot>();
}
}
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