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system.codecs

Description​

Contains information about compression and encryption codecs.

You can use this table to get information about the available compression and encryption codecs

Columns​

  • name (String) — Codec name.
  • method_byte (UInt8) — Byte which indicates codec in compressed file.
  • is_compression (UInt8) — True if this codec compresses something. Otherwise it can be just a transformation that helps compression.
  • is_generic_compression (UInt8) — The codec is a generic compression algorithm like lz4, zstd.
  • is_encryption (UInt8) — The codec encrypts.
  • is_timeseries_codec (UInt8) — The codec is for floating point timeseries codec.
  • is_experimental (UInt8) — The codec is experimental.
  • description (String) — A high-level description of the codec.

Example​

SELECT * FROM system.codecs WHERE name='LZ4'

Row 1:
──────
name:                   LZ4
method_byte:            130
is_compression:         1
is_generic_compression: 1
is_encryption:          0
is_timeseries_codec:    0
is_experimental:        0
description:            Extremely fast; good compression; balanced speed and efficiency.