TimescaleDB super table modification partition time of postgresql database (range)

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TimescaleDB super table modification partition time of postgresql database (range)

Before encountering a problem today, the super table created with TimescaleDB has been in units of 7 days. Because the amount of data in 7 days is too large, the query efficiency needs to be changed from 7 days to one day.
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Create a hypertable create_hypertable()

1. Create a regular version table

CREATE TABLE "超表名" (
  "collect_time" timestamp(6) NOT NULL,
  "code" varchar(36) COLLATE "pg_catalog"."default" NOT NULL,
  "value" numeric(14,4) NOT NULL,
  "create_time" timestamp(6) NOT NULL
)
;

2. Change to super table create_hypertable()

SELECT create_hypertable('超表名', 'collect_time', chunk_time_interval => INTERVAL '7 day');

3. Insert data

INSERT INTO 超表名("collect_time", "code", "value",  "create_time") VALUES ('2020-10-15 16:35:00', '22255220522', '23.4672',  '2020-10-14 16:35:26.659');
INSERT INTO 超表名("collect_time", "code", "value",  "create_time") VALUES ('2020-10-16 16:35:00', '26622569666', '0.1085',  '2020-10-14 16:35:27.546');
INSERT INTO 超表名("collect_time", "code", "value",  "create_time") VALUES ('2020-10-13 16:35:00', '525941155555', '25.0549',  '2020-10-14 16:35:28.473');
INSERT INTO 超表名("collect_time", "code", "value",  "create_time") VALUES ('2020-10-14 16:35:00', '744445411114', '0.0000',  '2020-10-14 16:35:24.01');
INSERT INTO 超表名("collect_time", "code", "value",  "create_time") VALUES ('2020-10-12 16:35:00', '774484457444', '0.0000',  '2020-10-14 16:35:23.032');

Check the partition, you will find that the data is in 2 partitions

Modify the partition set_chunk_time_interval()

1. Check the partition situation

1. View _timescaledb_catalog.dimension table

SELECT * FROM "_timescaledb_catalog"."dimension"

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604800000000 (TIMESTAMP type) is displayed on interval_length, which means one week
. 2. View the status of sub-blocks.
View the dimension_slice table.

Conversion timestamp
1602720000000000 2020-10-15 08:00:00
1603324800000000 2020-10-22 08:00:00
Here you can see the partition Is 7 days

2. Modify the partition time set_chunk_time_interval()

1. Modify the partition time

SELECT set_chunk_time_interval('超表名', interval '24 hours');

2. Insert data verification

INSERT INTO 超表名("collect_time", "code", "value", "create_time") VALUES ('2021-1-14 16:35:00', '375222D001', '27.7932', '2020-10-14 16:35:15.011');
INSERT INTO 超表名("collect_time", "code", "value", "create_time") VALUES ('2021-1-15 16:35:00', '3715044111', '0.0000',  '2020-10-14 16:35:20.389');
INSERT INTO 超表名("collect_time", "code", "value", "create_time") VALUES ('2021-1-16 16:35:00', '202Q0019QT001', '0.3663',  '2020-10-14 16:35:19.087');
INSERT INTO 超表名("collect_time", "code", "value", "create_time") VALUES ('2021-1-17 16:35:00', '3702000284441', '22.2946',  '2020-10-14 16:35:15.035');
INSERT INTO 超表名("collect_time", "code", "value", "create_time") VALUES ('2021-1-18 16:35:00', '37075225555501', '0.3022',  '2020-10-14 16:35:24.041');
INSERT INTO 超表名("collect_time", "code", "value", "create_time") VALUES ('2021-1-19 16:35:00', '25555222206001', '0.0000',  '2020-10-14 16:35:23.956');

Three. View the modified results

Look at the _timescaledb_catalog.dimension table and it Insert picture description here
becomes 86400000000.
2. Look at the partitions.
There are more partitions.

There is also the second type (not tested).
I wonder if I can directly "_timescaledb_catalog". The interval_length field of the "dimension" table is directly changed to 86400000000

Postgresql database TimescaleDB modify partition time (range)