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Merge pull request #3833 from yandex/remove-shard-by-hash

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Removed table function "shardByHash" because it has no use
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alexey-milovidov 2018-12-14 20:29:03 +03:00 committed by GitHub
commit eea8e2bbc2
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3 changed files with 0 additions and 118 deletions
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93
dbms/src/TableFunctions/TableFunctionShardByHash.cpp
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@ -1,93 +0,0 @@
#include <Storages/getStructureOfRemoteTable.h>
#include <Storages/StorageDistributed.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTFunction.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Interpreters/Cluster.h>
#include <Interpreters/Context.h>
#include <Interpreters/getClusterName.h>
#include <Common/SipHash.h>
#include <Common/typeid_cast.h>
#include <TableFunctions/TableFunctionShardByHash.h>
#include <TableFunctions/TableFunctionFactory.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int BAD_ARGUMENTS;
}
StoragePtr TableFunctionShardByHash::executeImpl(const ASTPtr & ast_function, const Context & context) const
{
ASTs & args_func = typeid_cast<ASTFunction &>(*ast_function).children;
const char * err = "Table function 'shardByHash' requires 4 parameters: "
"cluster name, key string to hash, name of remote database, name of remote table.";
if (args_func.size() != 1)
throw Exception(err, ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
ASTs & args = typeid_cast<ASTExpressionList &>(*args_func.at(0)).children;
if (args.size() != 4)
throw Exception(err, ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
String cluster_name;
String key;
String remote_database;
String remote_table;
auto getStringLiteral = [](const IAST & node, const char * description)
{
const ASTLiteral * lit = typeid_cast<const ASTLiteral *>(&node);
if (!lit)
throw Exception(description + String(" must be string literal (in single quotes)."), ErrorCodes::BAD_ARGUMENTS);
if (lit->value.getType() != Field::Types::String)
throw Exception(description + String(" must be string literal (in single quotes)."), ErrorCodes::BAD_ARGUMENTS);
return safeGet<const String &>(lit->value);
};
cluster_name = getClusterName(*args[0]);
key = getStringLiteral(*args[1], "Key to hash");
args[2] = evaluateConstantExpressionOrIdentifierAsLiteral(args[2], context);
args[3] = evaluateConstantExpressionOrIdentifierAsLiteral(args[3], context);
remote_database = static_cast<const ASTLiteral &>(*args[2]).value.safeGet<String>();
remote_table = static_cast<const ASTLiteral &>(*args[3]).value.safeGet<String>();
/// Similar to other TableFunctions.
for (auto & arg : args)
if (ASTIdentifier * id = typeid_cast<ASTIdentifier *>(arg.get()))
id->setSpecial();
auto cluster = context.getCluster(cluster_name);
size_t shard_index = sipHash64(key) % cluster->getShardCount();
std::shared_ptr<Cluster> shard(cluster->getClusterWithSingleShard(shard_index).release());
auto res = StorageDistributed::createWithOwnCluster(
getName(),
getStructureOfRemoteTable(*shard, remote_database, remote_table, context),
remote_database,
remote_table,
shard,
context);
res->startup();
return res;
}
void registerTableFunctionShardByHash(TableFunctionFactory & factory)
{
factory.registerFunction<TableFunctionShardByHash>();
}
}

23
dbms/src/TableFunctions/TableFunctionShardByHash.h
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@ -1,23 +0,0 @@
#pragma once
#include <TableFunctions/ITableFunction.h>
namespace DB
{
/* shardByHash(cluster, 'key', db, table) - creates a temporary StorageDistributed,
* using the cluster `cluster`, and selecting from it only one shard by hashing the string key.
*
* Similarly to the `remote` function, to get the table structure, a DESC TABLE request is made to the remote server.
*/
class TableFunctionShardByHash : public ITableFunction
{
public:
static constexpr auto name = "shardByHash";
std::string getName() const override { return name; }
private:
StoragePtr executeImpl(const ASTPtr & ast_function, const Context & context) const override;
};
}

2
dbms/src/TableFunctions/registerTableFunctions.cpp
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@ -8,7 +8,6 @@ namespace DB
void registerTableFunctionMerge(TableFunctionFactory & factory);
void registerTableFunctionRemote(TableFunctionFactory & factory);
void registerTableFunctionShardByHash(TableFunctionFactory & factory);
void registerTableFunctionNumbers(TableFunctionFactory & factory);
void registerTableFunctionCatBoostPool(TableFunctionFactory & factory);
void registerTableFunctionFile(TableFunctionFactory & factory);
@ -35,7 +34,6 @@ void registerTableFunctions()
registerTableFunctionMerge(factory);
registerTableFunctionRemote(factory);
registerTableFunctionShardByHash(factory);
registerTableFunctionNumbers(factory);
registerTableFunctionCatBoostPool(factory);
registerTableFunctionFile(factory);