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Unification of serde of data types: development [#CLICKHOUSE-2838].

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This commit is contained in:
Alexey Milovidov 2017-11-29 02:31:21 +03:00
parent cccf8aa8a8
commit 7b4bffe088
2 changed files with 40 additions and 11 deletions
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4
dbms/src/DataTypes/DataTypeArray.cpp
View File

@ -243,9 +243,7 @@ void DataTypeArray::deserializeBinaryBulkWithMultipleStreams(
/// Check consistency between offsets and elements subcolumns.
/// But if elements column is empty - it's ok for columns of Nested types that was added by ALTER.
if (nested_column.empty())
column_array.getOffsetsColumn() = column_array.getOffsetsColumn()->cloneEmpty();
else if (nested_column.size() != last_offset)
if (!nested_column.empty() && nested_column.size() != last_offset)
throw Exception("Cannot read all array values", ErrorCodes::CANNOT_READ_ALL_DATA);
}

47
dbms/src/Storages/MergeTree/MergeTreeReader.cpp
View File

@ -431,17 +431,35 @@ void MergeTreeReader::readData(
}
static bool arrayHasNoElementsRead(const IColumn & column)
{
const ColumnArray * column_array = typeid_cast<const ColumnArray *>(&column);
if (!column_array)
return false;
size_t size = column_array->size();
if (!size)
return false;
size_t data_size = column_array->getData().size();
if (data_size)
return false;
size_t last_offset = column_array->getOffsets()[size - 1];
return last_offset != 0;
}
void MergeTreeReader::fillMissingColumns(Block & res, const Names & ordered_names, bool always_reorder)
{
if (!res)
throw Exception("Empty block passed to fillMissingColumnsImpl", ErrorCodes::LOGICAL_ERROR);
throw Exception("Empty block passed to fillMissingColumns", ErrorCodes::LOGICAL_ERROR);
try
{
/// For a missing column of a nested data structure we must create not a column of empty
/// arrays, but a column of arrays of correct length.
/// TODO: If for some nested data structure only missing columns were selected, the arrays in these columns will be empty,
/// even if the offsets for this nested structure are present in the current part. This can be fixed.
/// NOTE: Similar, but slightly different code is present in Block::addDefaults.
/// First, collect offset columns for all arrays in the block.
@ -462,13 +480,26 @@ void MergeTreeReader::fillMissingColumns(Block & res, const Names & ordered_name
}
}
auto should_evaluate_defaults = false;
auto should_sort = always_reorder;
bool should_evaluate_defaults = false;
bool should_sort = always_reorder;
size_t rows = res.rows();
/// insert default values only for columns without default expressions
for (const auto & requested_column : columns)
{
/// insert default values only for columns without default expressions
if (!res.has(requested_column.name))
bool has_column = res.has(requested_column.name);
if (has_column)
{
const auto & col = *res.getByName(requested_column.name).column;
if (arrayHasNoElementsRead(col))
{
res.erase(requested_column.name);
has_column = false;
}
}
if (!has_column)
{
should_sort = true;
if (storage.column_defaults.count(requested_column.name) != 0)
@ -499,7 +530,7 @@ void MergeTreeReader::fillMissingColumns(Block & res, const Names & ordered_name
/// We must turn a constant column into a full column because the interpreter could infer that it is constant everywhere
/// but in some blocks (from other parts) it can be a full column.
column_to_add.column = column_to_add.type->createConstColumn(
res.rows(), column_to_add.type->getDefault())->convertToFullColumnIfConst();
rows, column_to_add.type->getDefault())->convertToFullColumnIfConst();
}
res.insert(std::move(column_to_add));