fix bug in ColumnLowCardinality::Load #270
Merged
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ColumnLowCardinality::Load
allocate the wrong amount rows forLowCardinality(Nullable(X))
columns. In most cases, it leads to extra memory allocation than required. But in case then the number of rows in a column is less than the dictionary size exception "can't load column 'some column' of type LowCardinality(Nullable(X))
" happened. The dictionary always contains null and default values. So if the column contains every unique value once and doesn't contain a null or default value, then such a situation happens.