chunk_compression_stats()
CommunityCommunity functions are available under Timescale Community Edition. Click to learn more.Get chunk-specific statistics related to hypertable compression. All sizes are in bytes.
This function shows the compressed size of chunks, computed when the
compress_chunk is manually executed, or when a compression policy processes
the chunk. An insert into a compressed chunk does not update the compressed
sizes. For more information about how to compute chunk sizes, see the
chunks_detailed_size section.
| Name | Type | Description |
|---|---|---|
hypertable | REGCLASS | Name of the hypertable |
| Column | Type | Description |
|---|---|---|
chunk_schema | TEXT | Schema name of the chunk |
chunk_name | TEXT | Name of the chunk |
compression_status | TEXT | the current compression status of the chunk |
before_compression_table_bytes | BIGINT | Size of the heap before compression (NULL if currently uncompressed) |
before_compression_index_bytes | BIGINT | Size of all the indexes before compression (NULL if currently uncompressed) |
before_compression_toast_bytes | BIGINT | Size the TOAST table before compression (NULL if currently uncompressed) |
before_compression_total_bytes | BIGINT | Size of the entire chunk table (table+indexes+toast) before compression (NULL if currently uncompressed) |
after_compression_table_bytes | BIGINT | Size of the heap after compression (NULL if currently uncompressed) |
after_compression_index_bytes | BIGINT | Size of all the indexes after compression (NULL if currently uncompressed) |
after_compression_toast_bytes | BIGINT | Size the TOAST table after compression (NULL if currently uncompressed) |
after_compression_total_bytes | BIGINT | Size of the entire chunk table (table+indexes+toast) after compression (NULL if currently uncompressed) |
node_name | TEXT | nodes on which the chunk is located, applicable only to distributed hypertables |
SELECT * FROM chunk_compression_stats('conditions')ORDER BY chunk_name LIMIT 2;-[ RECORD 1 ]------------------+----------------------chunk_schema | _timescaledb_internalchunk_name | _hyper_1_1_chunkcompression_status | Uncompressedbefore_compression_table_bytes |before_compression_index_bytes |before_compression_toast_bytes |before_compression_total_bytes |after_compression_table_bytes |after_compression_index_bytes |after_compression_toast_bytes |after_compression_total_bytes |node_name |-[ RECORD 2 ]------------------+----------------------chunk_schema | _timescaledb_internalchunk_name | _hyper_1_2_chunkcompression_status | Compressedbefore_compression_table_bytes | 8192before_compression_index_bytes | 32768before_compression_toast_bytes | 0before_compression_total_bytes | 40960after_compression_table_bytes | 8192after_compression_index_bytes | 32768after_compression_toast_bytes | 8192after_compression_total_bytes | 49152node_name |
Use pg_size_pretty get the output in a more human friendly format.
SELECT pg_size_pretty(after_compression_total_bytes) AS totalFROM chunk_compression_stats('conditions')WHERE compression_status = 'Compressed';-[ RECORD 1 ]--+------total | 48 kB
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