Description
Vortex is an extensible columnar file format for compressed Apache Arrow-compatible data, designed for fast scans and random access. ClickHouse supports reading and writing Vortex files.Data types matching
The table below shows the Vortex data types and the corresponding ClickHouse data types inINSERT and SELECT queries.
Other types are not supported. In particular, Map,
Int128/UInt128/Int256/UInt256, IPv6
and Interval columns cannot be written to Vortex files.
String columns are written as
Binary because ClickHouse strings are
arbitrary byte sequences, while Vortex requires Utf8 values to be valid UTF-8. Vortex has no
fixed-size binary type, so FixedString is also written as Binary,
and LowCardinality columns are written as their underlying type
(Vortex chooses dictionary and other encodings adaptively by itself).
DateTime columns are written as vortex.timestamp with second precision,
so they are read back as DateTime64 with scale 0.
IPv4 columns are written as U32 because Vortex has no type for IP addresses,
so schema inference reads them back as UInt32. Specify the type explicitly
to read such a column back as IPv4: SELECT * FROM file('data.vortex', Vortex, 'ip IPv4').
The data types of ClickHouse table columns do not have to match the corresponding Vortex data fields.
When inserting data, ClickHouse interprets data types according to the table above and then
casts the data to the data type set for the
ClickHouse table column.