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This commit adds initial support for the continuous aggregate materialization and INSERT invalidations. INSERT path: On INSERT, DELETE and UPDATE we log the [max, min] time range that may be invalidated (that is, newly inserted, updated, or deleted) to _timescaledb_catalog.continuous_aggs_hypertable_invalidation_log. This log will be used to re-materialize these ranges, to ensure that the aggregate is up-to-date. Currently these invalidations are recorded in by a trigger _timescaledb_internal.continuous_agg_invalidation_trigger, which should be added to the hypertable when the continuous aggregate is created. This trigger stores a cache of min/max values per-hypertable, and on transaction commit writes them to the log, if needed. At the moment, we consider them to always be needed, unless we're in ReadCommitted mode or weaker, and the min invalidated value is greater than the hypertable's invalidation threshold (found in _timescaledb_catalog.continuous_aggs_invalidation_threshold) Materialization path: Materialization currently happens in multiple phase: in phase 1 we determine the timestamp at which we will end the new set of materializations, then we update the hypertable's invalidation threshold to that point, and finally we read the current invalidations, then materialize any invalidated rows, the new range between the continuous aggregate's completed threshold (found in _timescaledb_catalog.continuous_aggs_completed_threshold) and the hypertable's invalidation threshold. After all of this is done we update the completed threshold to the invalidation threshold. The portion of this protocol from after the invalidations are read, until the completed threshold is written (that is, actually materializing, and writing the completion threshold) is included with this commit, with the remainder to follow in subsequent ones. One important caveat is that since the thresholds are exclusive, we invalidate all values _less_ than the invalidation threshold, and we store timevalue as an int64 internally, we cannot ever determine if the row at PG_INT64_MAX is invalidated. To avoid this problem, we never materialize the time bucket containing PG_INT64_MAX.
12 lines
650 B
SQL
12 lines
650 B
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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-- Trigger that blocks INSERTs on the hypertable's root table
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CREATE OR REPLACE FUNCTION _timescaledb_internal.insert_blocker() RETURNS trigger
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AS '@MODULE_PATHNAME@', 'ts_hypertable_insert_blocker' LANGUAGE C;
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-- Records mutations or INSERTs which would invalidate a continuous aggregate
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CREATE OR REPLACE FUNCTION _timescaledb_internal.continuous_agg_invalidation_trigger() RETURNS TRIGGER
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AS '@MODULE_PATHNAME@', 'continuous_agg_invalidation_trigger' LANGUAGE C;
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