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Merge pull request #23458 from kitaisreal/system-dictionaries-virtual-key-column

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System dictionaries virtual key column
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alexey-milovidov 2021-04-22 08:42:15 +03:00 committed by GitHub
commit 3df3acc970
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5 changed files with 55 additions and 3 deletions
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16
src/Storages/System/IStorageSystemOneBlock.h
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@ -12,7 +12,16 @@ namespace DB
class Context;
/** Base class for system tables whose all columns have String type.
/** IStorageSystemOneBlock is base class for system tables whose all columns can be synchronously fetched.
*
* Client class need to provide static method static NamesAndTypesList getNamesAndTypes() that will return list of column names and
* their types. IStorageSystemOneBlock during read will create result columns in same order as result of getNamesAndTypes
* and pass it with fillData method.
*
* Client also must override fillData and fill result columns.
*
* If subclass want to support virtual columns, it should override getVirtuals method of IStorage interface.
* IStorageSystemOneBlock will add virtuals columns at the end of result columns of fillData method.
*/
template <typename Self>
class IStorageSystemOneBlock : public IStorage
@ -41,9 +50,10 @@ public:
size_t /*max_block_size*/,
unsigned /*num_streams*/) override
{
metadata_snapshot->check(column_names, getVirtuals(), getStorageID());
auto virtuals_names_and_types = getVirtuals();
metadata_snapshot->check(column_names, virtuals_names_and_types, getStorageID());
Block sample_block = metadata_snapshot->getSampleBlock();
Block sample_block = metadata_snapshot->getSampleBlockWithVirtuals(virtuals_names_and_types);
MutableColumns res_columns = sample_block.cloneEmptyColumns();
fillData(res_columns, context, query_info);

10
src/Storages/System/StorageSystemDictionaries.cpp
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@ -50,6 +50,13 @@ NamesAndTypesList StorageSystemDictionaries::getNamesAndTypes()
};
}
NamesAndTypesList StorageSystemDictionaries::getVirtuals() const
{
return {
{"key", std::make_shared<DataTypeString>()}
};
}
void StorageSystemDictionaries::fillData(MutableColumns & res_columns, ContextPtr context, const SelectQueryInfo & /*query_info*/) const
{
const auto access = context->getAccess();
@ -128,6 +135,9 @@ void StorageSystemDictionaries::fillData(MutableColumns & res_columns, ContextPt
else
res_columns[i++]->insertDefault();
/// Start fill virtual columns
res_columns[i++]->insert(dictionary_structure.getKeyDescription());
}
}

2
src/Storages/System/StorageSystemDictionaries.h
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@ -18,6 +18,8 @@ public:
static NamesAndTypesList getNamesAndTypes();
NamesAndTypesList getVirtuals() const override;
protected:
using IStorageSystemOneBlock::IStorageSystemOneBlock;

4
tests/queries/0_stateless/01838_system_dictionaries_virtual_key_column.reference Normal file
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@ -0,0 +1,4 @@
simple key
example_simple_key_dictionary UInt64
complex key
example_complex_key_dictionary (UInt64, String)

26
tests/queries/0_stateless/01838_system_dictionaries_virtual_key_column.sql Normal file
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@ -0,0 +1,26 @@
DROP DICTIONARY IF EXISTS example_simple_key_dictionary;
CREATE DICTIONARY example_simple_key_dictionary (
id UInt64,
value UInt64
)
PRIMARY KEY id
SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() USER 'default' TABLE '' DATABASE currentDatabase()))
LAYOUT(DIRECT());
SELECT 'simple key';
SELECT name, key FROM system.dictionaries WHERE name='example_simple_key_dictionary' AND database=currentDatabase();
DROP DICTIONARY IF EXISTS example_complex_key_dictionary;
CREATE DICTIONARY example_complex_key_dictionary (
id UInt64,
id_key String,
value UInt64
)
PRIMARY KEY id, id_key
SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() USER 'default' TABLE '' DATABASE currentDatabase()))
LAYOUT(COMPLEX_KEY_DIRECT());
SELECT 'complex key';
SELECT name, key FROM system.dictionaries WHERE name='example_complex_key_dictionary' AND database=currentDatabase();