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https://github.com/timescale/timescaledb.git
synced 2025-05-17 19:13:16 +08:00
Reset compression sequence when group resets
The sequence number of the compressed tuple is per segment by grouping and should be reset when the grouping changes to prevent overflows with many segmentby columns.
This commit is contained in:
Sven Klemm
Sven Klemm
parent
0c6f4e2458
commit
131773a902
tsl
@ -897,6 +897,15 @@ row_compressor_flush(RowCompressor *row_compressor, CommandId mycid, bool change
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row_compressor->rowcnt_pre_compression += row_compressor->rows_compressed_into_current_value;
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row_compressor->num_compressed_rows++;
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row_compressor->rows_compressed_into_current_value = 0;
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/*
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* The sequence number of the compressed tuple is per segment by grouping
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* and should be reset when the grouping changes to prevent overflows with
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* many segmentby columns.
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*/
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if (changed_groups)
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row_compressor->sequence_num = SEQUENCE_NUM_GAP;
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MemoryContextReset(row_compressor->per_row_ctx);
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}
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@ -349,11 +349,11 @@ SELECT sum(_ts_meta_count) from :COMPRESSED_CHUNK_NAME;
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42
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(1 row)
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SELECT _ts_meta_sequence_num from :COMPRESSED_CHUNK_NAME;
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_ts_meta_sequence_num
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-----------------------
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10
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20
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SELECT location, _ts_meta_sequence_num from :COMPRESSED_CHUNK_NAME ORDER BY 1,2;
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location | _ts_meta_sequence_num
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----------+-----------------------
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NYC | 10
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POR | 10
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(2 rows)
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\x
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@ -1587,3 +1587,52 @@ SELECT count(*) FROM metrics;
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12961
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(1 row)
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-- test sequence number is local to segment by
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CREATE TABLE local_seq(time timestamptz, device int);
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SELECT table_name FROM create_hypertable('local_seq','time');
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NOTICE: adding not-null constraint to column "time"
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table_name
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------------
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local_seq
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(1 row)
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ALTER TABLE local_seq SET(timescaledb.compress,timescaledb.compress_segmentby='device');
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INSERT INTO local_seq SELECT '2000-01-01',1 FROM generate_series(1,3000);
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INSERT INTO local_seq SELECT '2000-01-01',2 FROM generate_series(1,3500);
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INSERT INTO local_seq SELECT '2000-01-01',3 FROM generate_series(1,3000);
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INSERT INTO local_seq SELECT '2000-01-01',4 FROM generate_series(1,3000);
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INSERT INTO local_seq SELECT '2000-01-01', generate_series(5,8);
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SELECT compress_chunk(c) FROM show_chunks('local_seq') c;
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compress_chunk
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------------------------------------------
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_timescaledb_internal._hyper_33_66_chunk
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(1 row)
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SELECT
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format('%s.%s',chunk.schema_name,chunk.table_name) AS "COMP_CHUNK"
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FROM _timescaledb_catalog.hypertable ht
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INNER JOIN _timescaledb_catalog.hypertable ht_comp ON ht_comp.id = ht.compressed_hypertable_id
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INNER JOIN _timescaledb_catalog.chunk ON chunk.hypertable_id = ht_comp.id
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WHERE ht.table_name = 'local_seq' \gset
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SELECT device, _ts_meta_sequence_num, _ts_meta_count FROM :COMP_CHUNK ORDER BY 1,2;
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device | _ts_meta_sequence_num | _ts_meta_count
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--------+-----------------------+----------------
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1 | 10 | 1000
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1 | 20 | 1000
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1 | 30 | 1000
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2 | 10 | 1000
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2 | 20 | 1000
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2 | 30 | 1000
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2 | 40 | 500
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3 | 10 | 1000
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3 | 20 | 1000
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3 | 30 | 1000
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4 | 10 | 1000
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4 | 20 | 1000
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4 | 30 | 1000
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5 | 10 | 1
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6 | 10 | 1
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7 | 10 | 1
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8 | 10 | 1
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(17 rows)
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@ -422,7 +422,7 @@ SELECT * FROM _timescaledb_internal.compress_hyper_3_6_chunk;
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time | device | temp | _ts_meta_count | _ts_meta_sequence_num | _ts_meta_min_1 | _ts_meta_max_1
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----------------------------------------------------------+--------+--------------------------------------------------------------------------------------------------------------------------------------------------+----------------+-----------------------+--------------------------+--------------------------
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BAAAAgna9rUEAAACCdr2tQQAAAAAAQAAAAEAAAAAAAAADgAEE7XtaggA | 1 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 10 | Thu Mar 08 01:00:00 2018 | Thu Mar 08 01:00:00 2018
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BAAAAgnaICFgAAACCdogIWAAAAAAAQAAAAEAAAAAAAAADgAEE7RAQsAA | 10 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 20 | Thu Mar 08 00:00:00 2018 | Thu Mar 08 00:00:00 2018
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BAAAAgnaICFgAAACCdogIWAAAAAAAQAAAAEAAAAAAAAADgAEE7RAQsAA | 10 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 10 | Thu Mar 08 00:00:00 2018 | Thu Mar 08 00:00:00 2018
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(2 rows)
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SELECT * FROM _timescaledb_internal._dist_hyper_3_12_chunk ORDER BY time;
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@ -466,7 +466,7 @@ SELECT * FROM _timescaledb_internal.compress_hyper_3_6_chunk;
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time | device | temp | _ts_meta_count | _ts_meta_sequence_num | _ts_meta_min_1 | _ts_meta_max_1
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----------------------------------------------------------+--------+--------------------------------------------------------------------------------------------------------------------------------------------------+----------------+-----------------------+--------------------------+--------------------------
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BAAAAgna9rUEAAACCdr2tQQAAAAAAQAAAAEAAAAAAAAADgAEE7XtaggA | 1 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 10 | Thu Mar 08 01:00:00 2018 | Thu Mar 08 01:00:00 2018
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BAAAAgnaICFgAAACCdogIWAAAAAAAQAAAAEAAAAAAAAADgAEE7RAQsAA | 10 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 20 | Thu Mar 08 00:00:00 2018 | Thu Mar 08 00:00:00 2018
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BAAAAgnaICFgAAACCdogIWAAAAAAAQAAAAEAAAAAAAAADgAEE7RAQsAA | 10 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 10 | Thu Mar 08 00:00:00 2018 | Thu Mar 08 00:00:00 2018
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(2 rows)
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SELECT * FROM _timescaledb_internal._dist_hyper_3_12_chunk ORDER BY time;
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@ -586,7 +586,7 @@ SELECT * FROM _timescaledb_internal.compress_hyper_3_6_chunk;
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time | device | temp | _ts_meta_count | _ts_meta_sequence_num | _ts_meta_min_1 | _ts_meta_max_1
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----------------------------------------------------------+--------+--------------------------------------------------------------------------------------------------------------------------------------------------+----------------+-----------------------+--------------------------+--------------------------
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BAAAAgna9rUEAAACCdr2tQQAAAAAAQAAAAEAAAAAAAAADgAEE7XtaggA | 1 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 10 | Thu Mar 08 01:00:00 2018 | Thu Mar 08 01:00:00 2018
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BAAAAgnaICFgAAACCdogIWAAAAAAAQAAAAEAAAAAAAAADgAEE7RAQsAA | 10 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 20 | Thu Mar 08 00:00:00 2018 | Thu Mar 08 00:00:00 2018
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BAAAAgnaICFgAAACCdogIWAAAAAAAQAAAAEAAAAAAAAADgAEE7RAQsAA | 10 | AwA/uZmZmZmZmgAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEAAAABAAAAAAAAAAEAAAAAAAAAAQAAAAEGAAAAAAAAAAIAAAABAAAAAQAAAAAAAAAGAAAAAAAAAD0AAAABPR/czMzMzMzN | 1 | 10 | Thu Mar 08 00:00:00 2018 | Thu Mar 08 00:00:00 2018
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(2 rows)
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SELECT * FROM _timescaledb_internal._dist_hyper_3_12_chunk ORDER BY time;
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@ -155,7 +155,7 @@ where uncompressed.compressed_chunk_id = compressed.id AND uncompressed.id = :'C
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SELECT count(*) from :CHUNK_NAME;
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SELECT count(*) from :COMPRESSED_CHUNK_NAME;
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SELECT sum(_ts_meta_count) from :COMPRESSED_CHUNK_NAME;
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SELECT _ts_meta_sequence_num from :COMPRESSED_CHUNK_NAME;
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SELECT location, _ts_meta_sequence_num from :COMPRESSED_CHUNK_NAME ORDER BY 1,2;
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\x
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SELECT chunk_id, numrows_pre_compression, numrows_post_compression
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@ -688,3 +688,26 @@ WHERE h.id = c.hypertable_id and h.table_name = 'metrics'
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ORDER BY 1;
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SELECT count(*) FROM metrics;
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-- test sequence number is local to segment by
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CREATE TABLE local_seq(time timestamptz, device int);
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SELECT table_name FROM create_hypertable('local_seq','time');
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ALTER TABLE local_seq SET(timescaledb.compress,timescaledb.compress_segmentby='device');
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INSERT INTO local_seq SELECT '2000-01-01',1 FROM generate_series(1,3000);
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INSERT INTO local_seq SELECT '2000-01-01',2 FROM generate_series(1,3500);
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INSERT INTO local_seq SELECT '2000-01-01',3 FROM generate_series(1,3000);
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INSERT INTO local_seq SELECT '2000-01-01',4 FROM generate_series(1,3000);
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INSERT INTO local_seq SELECT '2000-01-01', generate_series(5,8);
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SELECT compress_chunk(c) FROM show_chunks('local_seq') c;
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SELECT
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format('%s.%s',chunk.schema_name,chunk.table_name) AS "COMP_CHUNK"
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FROM _timescaledb_catalog.hypertable ht
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INNER JOIN _timescaledb_catalog.hypertable ht_comp ON ht_comp.id = ht.compressed_hypertable_id
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INNER JOIN _timescaledb_catalog.chunk ON chunk.hypertable_id = ht_comp.id
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WHERE ht.table_name = 'local_seq' \gset
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SELECT device, _ts_meta_sequence_num, _ts_meta_count FROM :COMP_CHUNK ORDER BY 1,2;
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