DioCrafts
173 lines
7.1 KiB
PL/PgSQL
173 lines
7.1 KiB
PL/PgSQL
\set ON_ERROR_STOP on
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\pset pager off
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\pset format unaligned
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\pset tuples_only on
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-- SUPERSEDED EXPLORATORY FIXTURE: every generated row shares one timestamp,
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-- so PostgreSQL posting-list compression understates representative btree
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-- storage cost. Keep this file only as raw historical evidence; do not use it
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-- to accept or reject an index. Use admin_user_order_index_representative.sql.
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-- A/B the missing ORDER BY index used by GET /api/admin/users. Two temporary
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-- tables keep both variants resident and let samples alternate without DDL
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-- contaminating timings. No persistent state survives the transaction.
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BEGIN;
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CREATE TEMP TABLE perf_users_no_index (
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id uuid NOT NULL,
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username text,
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email text NOT NULL,
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role_text text NOT NULL,
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storage_quota_bytes bigint NOT NULL,
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storage_used_bytes bigint NOT NULL,
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created_at timestamptz NOT NULL,
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last_login_at timestamptz,
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active boolean NOT NULL,
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oidc_provider text,
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is_external boolean NOT NULL
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);
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INSERT INTO perf_users_no_index
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SELECT
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gen_random_uuid(),
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'user-' || n,
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'user-' || n || '@example.invalid',
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CASE WHEN n % 20 = 0 THEN 'admin' ELSE 'user' END,
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10737418240,
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n::bigint * 1048576,
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-- One hundred accounts intentionally share each timestamp. The real
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-- default is statement-stable CURRENT_TIMESTAMP, so bulk/JIT creation can
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-- produce ties; `id` must make page boundaries deterministic.
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timestamptz '2026-01-01 00:00:00+00' + make_interval(secs => n / 100),
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timestamptz '2026-01-01 00:00:00+00' + make_interval(secs => n / 2),
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true,
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CASE WHEN n % 3 = 0 THEN 'keycloak' END,
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n % 7 = 0
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FROM generate_series(1, 500000) AS n;
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CREATE TEMP TABLE perf_users_indexed
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(LIKE perf_users_no_index INCLUDING ALL);
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INSERT INTO perf_users_indexed SELECT * FROM perf_users_no_index;
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CREATE INDEX perf_users_indexed_created_at_id
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ON perf_users_indexed (created_at DESC, id DESC);
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ANALYZE perf_users_no_index;
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ANALYZE perf_users_indexed;
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SELECT 'created_at_id_index_bytes|' || pg_relation_size('perf_users_indexed_created_at_id');
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SELECT 'tied_timestamp_groups|' || COUNT(*)
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FROM (
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SELECT created_at FROM perf_users_no_index GROUP BY created_at HAVING COUNT(*) > 1
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) tied;
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SELECT 'stable_order_match|' || (
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ARRAY(
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SELECT id FROM perf_users_no_index
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ORDER BY created_at DESC, id DESC LIMIT 200 OFFSET 49900
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) = ARRAY(
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SELECT id FROM perf_users_indexed
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ORDER BY created_at DESC, id DESC LIMIT 200 OFFSET 49900
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)
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);
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SELECT 'adjacent_page_overlap|' || COUNT(*)
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FROM (
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SELECT id FROM perf_users_indexed
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ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0
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) first_page
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JOIN (
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SELECT id FROM perf_users_indexed
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ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 100
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) second_page USING (id);
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\o /dev/null
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\timing on
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-- Warm both table variants and both page depths.
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\echo no_index_warmup_first
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SELECT id, username, email, role_text, storage_quota_bytes, storage_used_bytes,
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last_login_at, active, oidc_provider, is_external
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FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo indexed_warmup_first
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SELECT id, username, email, role_text, storage_quota_bytes, storage_used_bytes,
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last_login_at, active, oidc_provider, is_external
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FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo no_index_warmup_deep
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SELECT id, username, email, role_text, storage_quota_bytes, storage_used_bytes,
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last_login_at, active, oidc_provider, is_external
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FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo indexed_warmup_deep
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SELECT id, username, email, role_text, storage_quota_bytes, storage_used_bytes,
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last_login_at, active, oidc_provider, is_external
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FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo no_index_first_1
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo indexed_first_1
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo indexed_deep_1
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo no_index_deep_1
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo indexed_first_2
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo no_index_first_2
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo no_index_deep_2
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo indexed_deep_2
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo no_index_first_3
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo indexed_first_3
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo indexed_deep_3
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo no_index_deep_3
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo indexed_first_4
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo no_index_first_4
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo no_index_deep_4
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo indexed_deep_4
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo no_index_first_5
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo indexed_first_5
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 0;
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\echo indexed_deep_5
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SELECT * FROM perf_users_indexed ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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\echo no_index_deep_5
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SELECT * FROM perf_users_no_index ORDER BY created_at DESC, id DESC LIMIT 100 OFFSET 50000;
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-- Write-cost gate: an ordering index is not free. Copy the same 10k-row shape
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-- into each variant and report the insertion tax alongside the read win.
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\echo no_index_insert_1
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INSERT INTO perf_users_no_index SELECT * FROM perf_users_no_index LIMIT 10000;
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\echo indexed_insert_1
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INSERT INTO perf_users_indexed SELECT * FROM perf_users_indexed LIMIT 10000;
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\echo indexed_insert_2
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INSERT INTO perf_users_indexed SELECT * FROM perf_users_indexed LIMIT 10000;
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\echo no_index_insert_2
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INSERT INTO perf_users_no_index SELECT * FROM perf_users_no_index LIMIT 10000;
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\echo no_index_insert_3
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INSERT INTO perf_users_no_index SELECT * FROM perf_users_no_index LIMIT 10000;
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\echo indexed_insert_3
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INSERT INTO perf_users_indexed SELECT * FROM perf_users_indexed LIMIT 10000;
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\echo indexed_insert_4
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INSERT INTO perf_users_indexed SELECT * FROM perf_users_indexed LIMIT 10000;
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\echo no_index_insert_4
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INSERT INTO perf_users_no_index SELECT * FROM perf_users_no_index LIMIT 10000;
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\echo no_index_insert_5
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INSERT INTO perf_users_no_index SELECT * FROM perf_users_no_index LIMIT 10000;
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\echo indexed_insert_5
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INSERT INTO perf_users_indexed SELECT * FROM perf_users_indexed LIMIT 10000;
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\timing off
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\o
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ROLLBACK;
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