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6a9db8a621
A new function, `get_chunk_relstats()`, allows fetching relstats
(basically `pg_class.{relpages,reltuples`) from remote chunks on data
nodes and writing it to the `pg_class` entry for the corresponding
local chunk. The function expects either a chunk or a hypertable as
input and returns the relstats for the given chunk or all chunks for
the given hypertable, respectively.
Importing relstats as described is useful as part of a distributed
ANALYZE/VACUUM that won't require fetching all data into the access
node for local sampling (like the current implemention does).
In a future change, this function will be called as part of a local
ANALYZE on the access node that runs ANALYZE on all data nodes
followed by importing of the resulting relstats for the analyzed
chunks.
64 lines
3.3 KiB
SQL
64 lines
3.3 KiB
SQL
-- This file and its contents are licensed under the Apache License 2.0.
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-- Please see the included NOTICE for copyright information and
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-- LICENSE-APACHE for a copy of the license.
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-- Built-in function for calculating the next chunk interval when
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-- using adaptive chunking. The function can be replaced by a
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-- user-defined function with the same signature.
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--
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-- The parameters passed to the function are as follows:
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--
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-- dimension_id: the ID of the dimension to calculate the interval for
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-- dimension_coord: the coordinate / point on the dimensional axis
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-- where the tuple that triggered this chunk creation falls.
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-- chunk_target_size: the target size in bytes that the chunk should have.
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--
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-- The function should return the new interval in dimension-specific
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-- time (ususally microseconds).
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CREATE OR REPLACE FUNCTION _timescaledb_internal.calculate_chunk_interval(
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dimension_id INTEGER,
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dimension_coord BIGINT,
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chunk_target_size BIGINT
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) RETURNS BIGINT AS '@MODULE_PATHNAME@', 'ts_calculate_chunk_interval' LANGUAGE C;
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-- Function for explicit chunk exclusion. Supply a record and an array
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-- of chunk ids as input.
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-- Intended to be used in WHERE clause.
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-- An example: SELECT * FROM hypertable WHERE _timescaledb_internal.chunks_in(hypertable, ARRAY[1,2]);
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--
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-- Use it with care as this function directly affects what chunks are being scanned for data.
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-- This is a marker function and should never be executed (we remove it from the plan)
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CREATE OR REPLACE FUNCTION _timescaledb_internal.chunks_in(record RECORD, chunks INTEGER[]) RETURNS BOOL
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AS '@MODULE_PATHNAME@', 'ts_chunks_in' LANGUAGE C STABLE STRICT PARALLEL SAFE;
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--given a chunk's relid, return the id. Error out if not a chunk relid.
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CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_id_from_relid(relid OID) RETURNS INTEGER
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AS '@MODULE_PATHNAME@', 'ts_chunk_id_from_relid' LANGUAGE C STABLE STRICT PARALLEL SAFE;
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--trigger to block dml on a chunk --
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CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_dml_blocker() RETURNS trigger
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AS '@MODULE_PATHNAME@', 'ts_chunk_dml_blocker' LANGUAGE C;
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-- Show the definition of a chunk.
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CREATE OR REPLACE FUNCTION _timescaledb_internal.show_chunk(chunk REGCLASS)
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RETURNS TABLE(chunk_id INTEGER, hypertable_id INTEGER, schema_name NAME, table_name NAME, relkind "char", slices JSONB)
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AS '@MODULE_PATHNAME@', 'ts_chunk_show' LANGUAGE C VOLATILE;
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-- Create a chunk with the given dimensional constraints (slices) as given in the JSONB.
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CREATE OR REPLACE FUNCTION _timescaledb_internal.create_chunk(
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hypertable REGCLASS,
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slices JSONB,
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schema_name NAME = NULL,
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table_name NAME = NULL)
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RETURNS TABLE(chunk_id INTEGER, hypertable_id INTEGER, schema_name NAME, table_name NAME, relkind "char", slices JSONB, created BOOLEAN)
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AS '@MODULE_PATHNAME@', 'ts_chunk_create' LANGUAGE C VOLATILE;
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-- change default data node for a chunk
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CREATE OR REPLACE FUNCTION _timescaledb_internal.set_chunk_default_data_node(chunk REGCLASS, node_name NAME) RETURNS BOOLEAN
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AS '@MODULE_PATHNAME@', 'ts_chunk_set_default_data_node' LANGUAGE C VOLATILE;
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-- Get chunk stats.
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CREATE OR REPLACE FUNCTION _timescaledb_internal.get_chunk_relstats(relid REGCLASS)
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RETURNS TABLE(chunk_id INTEGER, hypertable_id INTEGER, num_pages INTEGER, num_tuples REAL, num_allvisible INTEGER)
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AS '@MODULE_PATHNAME@', 'ts_chunk_get_relstats' LANGUAGE C VOLATILE;
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