From b916ab9e3187046325f02cc7367a13fa848abdee Mon Sep 17 00:00:00 2001 From: dullbananas Date: Sat, 30 Dec 2023 09:48:14 -0700 Subject: [PATCH] try to fix create_triggers --- replaceable_schema.sql | 264 +++++++++++++++++++---------------------- 1 file changed, 123 insertions(+), 141 deletions(-) diff --git a/replaceable_schema.sql b/replaceable_schema.sql index 7e0ae2e66..5a9385cc9 100644 --- a/replaceable_schema.sql +++ b/replaceable_schema.sql @@ -36,74 +36,105 @@ BEGIN END $$; --- Create functions that select both old and new rows in a trigger. Column 1 is `-1` if old and `1` if new, --- which can be used with `sum` to get the number to add to a count. Column 2 is the original row as a composite --- value. A separate function is called in each `IF` statement to prevent an error from referencing transition --- tables that don't exist. All of this could be one function, but that would require using `RETURN QUERY EXECUTE` --- instead of calls to separate functions because of PostgreSQL's limited polymorphism. Parsing and planning dynamic --- queries at runtime is worse for performance. -CREATE PROCEDURE r.combine_transition_tables_function (table_name text) +-- This function creates statement-level triggers for all operation types. It's designed this way +-- because of these limitations: +-- * A trigger that uses transition tables can only handle 1 operation type. +-- * Transition tables must be relevant for the operation type (for example, `NEW TABLE` is +-- not allowed for a `DELETE` trigger) +-- * Transition tables are only provided to the trigger function, not to functions that it calls. +-- +-- This function can only be called once per table. The command to run is given as the 2nd argument +-- and has access to these tables: +-- * `old_table` with old rows +-- * `new_table` with new rows +-- * `combined_transition_tables` with both old and new rows, with 2 columns: +-- 1. `-1` for old rows and `1` for new rows, which can be used with `sum` to get the number +-- to add to a count +-- 2. the old or new row as a composite value +CREATE PROCEDURE r.create_triggers (table_name text, command text) LANGUAGE plpgsql AS $a$ +DECLARE + defs text := $b$ + CREATE FUNCTION r.thing_delete_statement () + RETURNS TRIGGER + LANGUAGE plpgsql + AS $$ + BEGIN + PERFORM ( + WITH + combined_transition_tables AS ( + select_old_table + ), + trigger_result AS command + SELECT + 1 + ); + RETURN NULL; + END + $$; + CREATE TRIGGER delete_statement + AFTER DELETE ON thing REFERENCING OLD TABLE AS old_table + FOR EACH STATEMENT + EXECUTE FUNCTION r.thing_delete_statement (); + CREATE FUNCTION r.thing_insert_statement () + RETURNS TRIGGER + LANGUAGE plpgsql + AS $$ + BEGIN + PERFORM ( + WITH + combined_transition_tables AS ( + select_new_table + ), + trigger_result AS command + SELECT + 1 + ); + RETURN NULL; + END + $$; + CREATE TRIGGER insert_statement + AFTER DELETE ON thing REFERENCING NEW TABLE AS new_table + FOR EACH STATEMENT + EXECUTE FUNCTION r.thing_insert_statement (); + CREATE FUNCTION r.thing_update_statement () + RETURNS TRIGGER + LANGUAGE plpgsql + AS $$ + BEGIN + PERFORM ( + WITH + combined_transition_tables AS ( + select_old_table + UNION ALL + select_new_table + ), + trigger_result AS command + SELECT + 1 + ); + RETURN NULL; + END + $$; + CREATE TRIGGER update_statement + AFTER UPDATE ON thing REFERENCING OLD TABLE AS old_table NEW TABLE AS new_table + FOR EACH STATEMENT + EXECUTE FUNCTION r.thing_update_statement (); + $b$; BEGIN - EXECUTE replace($b$ - CREATE FUNCTION r.get_old_thing_rows () - RETURNS SETOF record - LANGUAGE plpgsql - AS $$ - BEGIN - RETURN QUERY SELECT -1, old_table FROM old_table; - RETURN; - END - $$; - CREATE FUNCTION r.get_new_thing_rows () - RETURNS SETOF record - LANGUAGE plpgsql - AS $$ - BEGIN - RETURN QUERY SELECT 1, new_table FROM new_table; - RETURN; - END - $$; - CREATE FUNCTION r.combine_thing_transition_tables (tg_op text) - RETURNS SETOF record - LANGUAGE plpgsql - AS $$ - BEGIN - IF (TG_OP IN ('UPDATE', 'DELETE')) THEN - RETURN QUERY SELECT * FROM r.get_old_thing_rows () AS (count_diff bigint, thing thing); - END IF; - IF (TG_OP IN ('UPDATE', 'INSERT')) THEN - RETURN QUERY SELECT * FROM r.get_new_thing_rows () AS (count_diff bigint, thing thing); - END IF; - RETURN; - END - $$; - $b$, 'thing', table_name); + defs := replace(defs, 'select_old_table', $$ + SELECT -1 AS count_diff, old_table AS thing FROM old_table + $$); + defs := replace(defs, 'select_new_table', $$ + SELECT 1 AS count_diff, new_table AS thing FROM new_table + $$); + defs := replace(defs, 'thing', table_name); + defs := replace(defs, 'command', format('(%s)', command)); + EXECUTE defs; END $a$; -CALL r.combine_transition_tables_function('comment'); - -CALL r.combine_transition_tables_function('community'); - -CALL r.combine_transition_tables_function('community_follower'); - -CALL r.combine_transition_tables_function('person'); - -CALL r.combine_transition_tables_function('post'); - --- Creates triggers for all operation types, which can't be 1 trigger when transition tables are used -CREATE PROCEDURE r.create_triggers (table_name text, function_name text) -LANGUAGE plpgsql -AS $$ -BEGIN - EXECUTE format('CREATE TRIGGER %2$s_insert AFTER INSERT ON %1$s REFERENCING NEW TABLE AS new_table FOR EACH STATEMENT EXECUTE FUNCTION r.%2$s ();', table_name, function_name); - EXECUTE format('CREATE TRIGGER %2$s_delete AFTER DELETE ON %1$s REFERENCING OLD TABLE AS old_table FOR EACH STATEMENT EXECUTE FUNCTION r.%2$s ();', table_name, function_name); - EXECUTE format('CREATE TRIGGER %2$s_update AFTER UPDATE ON %1$s REFERENCING OLD TABLE AS old_table NEW TABLE AS new_table FOR EACH STATEMENT EXECUTE FUNCTION r.%2$s ();', table_name, function_name); -END -$$; - -- Define functions CREATE FUNCTION r.creator_id_from_post_aggregates (agg post_aggregates) RETURNS int RETURN agg.creator_id; @@ -149,12 +180,8 @@ BEGIN FOR EACH STATEMENT EXECUTE FUNCTION r.resolve_reports_when_thing_removed ( ); -- When a thing gets a vote, update its aggregates and its creator's aggregates - CREATE FUNCTION r.thing_aggregates_from_like ( ) - RETURNS TRIGGER - LANGUAGE plpgsql - AS $$ - BEGIN - WITH thing_diff AS ( + CALL r.create_triggers ('thing_like', $$ + WITH thing_diff AS ( UPDATE thing_aggregates AS a SET @@ -168,7 +195,7 @@ BEGIN sum(count_diff) FILTER (WHERE (thing_like).score = 1) AS upvotes, sum(count_diff) FILTER (WHERE (thing_like).score != 1) AS downvotes FROM - r.combine_thing_transition_tables (TG_OP) + combined_transition_tables AS (count_diff bigint, thing_like thing_like) GROUP BY @@ -191,13 +218,8 @@ BEGIN GROUP BY creator_id) AS diff WHERE - a.person_id = diff.creator_id; - RETURN NULL; - END $$; - CALL r.create_triggers ('thing_like', 'thing_aggregates_from_like'); - $b$, - 'thing', - thing_type); + a.person_id = diff.creator_id + $$); END $a$; @@ -206,11 +228,7 @@ CALL r.post_or_comment ('post'); CALL r.post_or_comment ('comment'); -- Create triggers that update counts in parent aggregates -CREATE FUNCTION r.parent_aggregates_from_comment () - RETURNS TRIGGER - LANGUAGE plpgsql - AS $$ -BEGIN +CALL r.create_triggers('comment', $$ WITH comment_group AS ( SELECT (comment).post_id, @@ -218,7 +236,7 @@ BEGIN (comment).local, sum(count_diff) AS comments FROM - r.combine_comment_transition_tables (TG_OP) + combined_transition_tables AS (count_diff bigint, comment comment) WHERE @@ -302,18 +320,10 @@ FROM ( GROUP BY community_id) AS diff WHERE - a.community_id = diff.community_id; - RETURN NULL; -END -$$; + a.community_id = diff.community_id + $$); -CALL r.create_triggers ('comment', 'parent_aggregates_from_comment'); - -CREATE FUNCTION r.parent_aggregates_from_post () - RETURNS TRIGGER - LANGUAGE plpgsql - AS $$ -BEGIN +CALL r.create_triggers('post', $$ WITH post_group AS ( SELECT (post).community_id, @@ -321,7 +331,7 @@ BEGIN (post).local, sum(count_diff) AS posts FROM - r.combine_post_transition_tables (TG_OP) + combined_post_transition_tables AS (count_diff bigint, post post) WHERE @@ -357,18 +367,10 @@ SET FROM post_group WHERE - a.community_id = post_group.community_id; - RETURN NULL; -END -$$; + a.community_id = post_group.community_id + $$); -CALL r.create_triggers ('post', 'parent_aggregates_from_post'); - -CREATE FUNCTION r.site_aggregates_from_community () - RETURNS TRIGGER - LANGUAGE plpgsql - AS $$ -BEGIN +CALL r.create_triggers('community', $$ UPDATE site_aggregates AS a SET @@ -377,20 +379,12 @@ BEGIN SELECT sum(count_diff) AS communities FROM - r.combine_community_transition_tables (TG_OP) + combined_transition_tables AS (count_diff bigint, community community) - WHERE (community).local AND NOT ((community).deleted OR (community).removed)) AS diff; - RETURN NULL; -END -$$; + WHERE (community).local AND NOT ((community).deleted OR (community).removed)) AS diff + $$); -CALL r.create_triggers ('community', 'site_aggregates_from_community'); - -CREATE FUNCTION r.site_aggregates_from_person () - RETURNS TRIGGER - LANGUAGE plpgsql - AS $$ -BEGIN +CALL r.create_triggers('person', $$ UPDATE site_aggregates AS a SET @@ -399,14 +393,10 @@ BEGIN SELECT sum(count_diff) AS users FROM - r.combine_person_transition_tables (TG_OP) + combined_transition_tables AS (count_diff bigint, person person) - WHERE (person).local) AS diff; - RETURN NULL; -END -$$; - -CALL r.create_triggers ('person', 'site_aggregates_from_person'); + WHERE (person).local) AS diff + $$); -- For community_aggregates.comments, don't include comments of deleted or removed posts CREATE FUNCTION r.update_comment_count_from_post () @@ -456,11 +446,7 @@ CREATE TRIGGER comment_count EXECUTE FUNCTION r.update_comment_count_from_post (); -- Count subscribers for local communities -CREATE FUNCTION r.community_aggregates_from_subscriber () - RETURNS TRIGGER - LANGUAGE plpgsql - AS $$ -BEGIN +CALL r.create_triggers ('community_follower', $$ UPDATE community_aggregates AS a SET @@ -470,7 +456,7 @@ BEGIN (community_follower).community_id, sum(count_diff) AS subscribers FROM - r.combine_community_follower_transition_tables (TG_OP) + combine_transition_tables AS (count_diff bigint, community_follower community_follower) WHERE ( SELECT @@ -483,12 +469,8 @@ BEGIN GROUP BY (community_follower).community_id) AS diff WHERE - a.community_id = diff.community_id; - RETURN NULL; -END -$$; - -CALL r.create_triggers ('community_follower', 'community_aggregates_from_subscriber'); + a.community_id = diff.community_id + $$); -- These triggers create and update rows in each aggregates table to match its associated table's rows. -- Deleting rows and updating IDs are already handled by `CASCADE` in foreign key constraints. @@ -581,6 +563,11 @@ BEGIN END $$; +CREATE TRIGGER aggregates + AFTER INSERT ON post REFERENCING NEW TABLE AS new_post + FOR EACH STATEMENT + EXECUTE FUNCTION r.post_aggregates_from_post (); + CREATE FUNCTION r.post_aggregates_from_post_update () RETURNS TRIGGER LANGUAGE plpgsql @@ -599,11 +586,6 @@ BEGIN END $$; -CREATE TRIGGER aggregates - AFTER INSERT ON post REFERENCING NEW TABLE AS new_post - FOR EACH STATEMENT - EXECUTE FUNCTION r.post_aggregates_from_post (); - CREATE TRIGGER aggregates_update AFTER UPDATE ON post REFERENCING NEW TABLE AS new_post FOR EACH STATEMENT