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https://github.com/timescale/timescaledb.git
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19239ff8dd
Add a function that can be used on a compressed data value to show some metadata information, such as the compression algorithm used and the presence of any null values.
72 lines
2.9 KiB
SQL
72 lines
2.9 KiB
SQL
-- This file and its contents are licensed under the Timescale License.
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-- Please see the included NOTICE for copyright information and
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-- LICENSE-TIMESCALE for a copy of the license.
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\set ECHO errors
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DROP TABLE IF EXISTS compressed;
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CREATE TABLE compressed AS SELECT :COMPRESSION_CMD AS c FROM (:QUERY) AS sub;
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SELECT (_timescaledb_functions.compressed_data_info(c)).*,
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pg_column_size(c) as "compressed size"
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FROM compressed;
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--rewrite table (needed to make sure the compressed data does not reference toast table of original)
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CREATE TABLE temp AS SELECT * FROM :TABLE_NAME;
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DROP TABLE :TABLE_NAME;
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ALTER TABLE temp RENAME TO :TABLE_NAME;
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--test that decompression gives same result in forward direction
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with original AS (
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SELECT row_number() OVER() row_number, * FROM (:QUERY) as q
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),
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decompressed AS (
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SELECT row_number() OVER () row_number, * FROM (SELECT :DECOMPRESS_FORWARD_CMD FROM compressed) as q
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)
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SELECT 'Number of rows different between original and decompressed forward (expect 0)', count(*)
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FROM original
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FULL OUTER JOIN decompressed ON (original.row_number = decompressed.row_number)
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WHERE (original.*) IS DISTINCT FROM (decompressed.*);
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--test the decompress reverse direction too
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with count_orig AS (
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SELECT count(*) as cnt FROM (:QUERY) as q
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),
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original AS (
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SELECT count_orig.cnt + 1 - row_number() OVER() row_number, q.* FROM (:QUERY) as q, count_orig
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),
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decompressed AS (
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SELECT row_number() OVER () row_number, * FROM (SELECT :DECOMPRESS_REVERSE_CMD FROM compressed) as q
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)
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SELECT 'Number of rows different between original and decompressed reversed (expect 0)', count(*)
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FROM original
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FULL OUTER JOIN decompressed ON (original.row_number = decompressed.row_number)
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WHERE (original.*) IS DISTINCT FROM (decompressed.*);
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--Test IO
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SELECT c "COMPRESSED_AS_TEXT" FROM compressed \gset
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WITH original AS
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(
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SELECT row_number() OVER() row_number, * FROM (:QUERY) as q
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),
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decompressed AS
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(
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SELECT row_number() OVER () row_number, * FROM (SELECT :DECOMPRESS_FORWARD_CMD FROM compressed) as q
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),
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decompressed_from_text AS (
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SELECT row_number() OVER () row_number, * FROM (SELECT :DECOMPRESS_FORWARD_CMD FROM (SELECT :'COMPRESSED_AS_TEXT'::text as c) as txt) as q
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)
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SELECT 'Number of rows different between original, decompressed, and decompressed deserializeed (expect 0)', count(*)
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FROM original
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FULL OUTER JOIN decompressed ON (original.row_number = decompressed.row_number)
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FULL OUTER JOIN decompressed_from_text ON (original.row_number = decompressed_from_text.row_number)
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WHERE (original.*) IS DISTINCT FROM (decompressed_from_text.*) OR (decompressed.*) IS DISTINCT FROM (decompressed_from_text.*) ;
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SELECT
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'Test that deserialization, decompression, recompression, and serialization results in the same text',
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:COMPRESSION_CMD::text IS NOT DISTINCT FROM :'COMPRESSED_AS_TEXT'
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FROM
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(SELECT :DECOMPRESS_FORWARD_CMD as item FROM (SELECT :'COMPRESSED_AS_TEXT'::text as c) as txt) as decompressed_serialized;
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\set ECHO all
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