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70c549dad8
* Speeding up comment-ltree migration, fixing index creation. Fixes #2664 * Adding some logging lines, fixing for missing posts. * Adding more postgres config
119 lines
4.2 KiB
SQL
119 lines
4.2 KiB
SQL
-- Remove the comment.read column, and create a new comment_reply table,
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-- similar to the person_mention table.
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--
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-- This is necessary because self-joins using ltrees would be too tough with SQL views
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--
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-- Every comment should have a row here, because all comments have a recipient,
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-- either the post creator, or the parent commenter.
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create table comment_reply(
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id serial primary key,
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recipient_id int references person on update cascade on delete cascade not null,
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comment_id int references comment on update cascade on delete cascade not null,
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read boolean default false not null,
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published timestamp not null default now(),
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unique(recipient_id, comment_id)
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);
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-- Ones where parent_id is null, use the post creator recipient
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insert into comment_reply (recipient_id, comment_id, read)
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select p.creator_id, c.id, c.read from comment c
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inner join post p on c.post_id = p.id
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where c.parent_id is null;
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-- Ones where there is a parent_id, self join to comment to get the parent comment creator
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insert into comment_reply (recipient_id, comment_id, read)
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select c2.creator_id, c.id, c.read from comment c
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inner join comment c2 on c.parent_id = c2.id;
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-- Drop comment_alias view
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drop view comment_alias_1;
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alter table comment drop column read;
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create extension ltree;
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alter table comment add column path ltree not null default '0';
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alter table comment_aggregates add column child_count integer not null default 0;
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-- The ltree path column should be the comment_id parent paths, separated by dots.
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-- Stackoverflow: building an ltree from a parent_id hierarchical tree:
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-- https://stackoverflow.com/a/1144848/1655478
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create temporary table comment_temp as
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WITH RECURSIVE q AS (
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SELECT h, 1 AS level, ARRAY[id] AS breadcrumb
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FROM comment h
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WHERE parent_id is null
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UNION ALL
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SELECT hi, q.level + 1 AS level, breadcrumb || id
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FROM q
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JOIN comment hi
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ON hi.parent_id = (q.h).id
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)
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SELECT (q.h).id,
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(q.h).parent_id,
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level,
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breadcrumb::VARCHAR AS path,
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text2ltree('0.' || array_to_string(breadcrumb, '.')) as ltree_path
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FROM q
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ORDER BY
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breadcrumb;
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-- Remove indexes and foreign key constraints, and disable triggers for faster updates
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alter table comment disable trigger all;
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alter table comment drop constraint if exists comment_creator_id_fkey;
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alter table comment drop constraint if exists comment_parent_id_fkey;
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alter table comment drop constraint if exists comment_post_id_fkey;
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alter table comment drop constraint if exists idx_comment_ap_id;
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drop index if exists idx_comment_creator;
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drop index if exists idx_comment_parent;
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drop index if exists idx_comment_post;
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drop index if exists idx_comment_published;
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-- Add the ltree column
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update comment c
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set path = ct.ltree_path
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from comment_temp ct
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where c.id = ct.id;
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-- Update the child counts
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update comment_aggregates ca set child_count = c2.child_count
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from (
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select c.id, c.path, count(c2.id) as child_count from comment c
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left join comment c2 on c2.path <@ c.path and c2.path != c.path
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group by c.id
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) as c2
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where ca.comment_id = c2.id;
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-- Delete comments at a depth of > 150, otherwise the index creation below will fail
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delete from comment where nlevel(path) > 150;
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-- Delete from comment where there is a missing post
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delete from comment c where not exists (
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select from post p where p.id = c.post_id
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);
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-- Delete from comment where there is a missing creator_id
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delete from comment c where not exists (
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select from person p where p.id = c.creator_id
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);
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-- Re-enable old constraints and indexes
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alter table comment add constraint "comment_creator_id_fkey" FOREIGN KEY (creator_id) REFERENCES person(id) ON UPDATE CASCADE ON DELETE CASCADE;
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alter table comment add constraint "comment_post_id_fkey" FOREIGN KEY (post_id) REFERENCES post(id) ON UPDATE CASCADE ON DELETE CASCADE;
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alter table comment add constraint "idx_comment_ap_id" unique (ap_id);
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create index idx_comment_creator on comment (creator_id);
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create index idx_comment_post on comment (post_id);
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create index idx_comment_published on comment (published desc);
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-- Create the index
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create index idx_path_gist on comment using gist (path);
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-- Drop the parent_id column
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alter table comment drop column parent_id cascade;
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alter table comment enable trigger all;
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