-- test/sql/parallel_build.sql
-- Regression test for parallel CREATE INDEX (amcanbuildparallel = true,
-- pg_tre.enable_parallel_build on by default).
--
-- Parallel builds scan, sort AND build posting trees in parallel (4.3.1:
-- each participant claims trigram-hash ranges and writes their posting
-- trees; the leader then builds the upper tree and SuRF in hash order).
-- This test confirms:
--
--   1. A parallel build succeeds and produces a valid index.
--   2. The parallel-built index returns exactly the same rows as a
--      seq scan (the correctness gate: no tuple is lost or duplicated
--      across the participant split).
--   3. A serial build of the same data answers identically.
CREATE EXTENSION IF NOT EXISTS pg_tre;
psql:test/sql/parallel_build.sql:16: NOTICE:  extension "pg_tre" already exists, skipping
CREATE EXTENSION
DROP TABLE IF EXISTS pbuild_t CASCADE;
psql:test/sql/parallel_build.sql:18: NOTICE:  table "pbuild_t" does not exist, skipping
DROP TABLE
CREATE TABLE pbuild_t (id serial, body text);
CREATE TABLE
INSERT INTO pbuild_t (body)
SELECT md5(i::text) || ' error' || (i % 100) || ' token' || (i % 13)
FROM generate_series(1, 20000) AS i;
INSERT 0 20000
-- Force the planner to assign build workers regardless of table size.
SET max_parallel_maintenance_workers = 4;
SET
SET max_parallel_workers = 8;
SET
SET min_parallel_table_scan_size = 0;
SET
SET maintenance_work_mem = '32MB';
SET
SET pg_tre.enable_parallel_build = on;
SET
SET client_min_messages = warning;   -- suppress per-build NOTICEs (worker count varies)
SET
CREATE INDEX pbuild_par ON pbuild_t USING tre (body);
CREATE INDEX
-- Index must be valid.
SELECT indisvalid, indisready FROM pg_index
WHERE indexrelid = 'pbuild_par'::regclass;
 indisvalid | indisready 
------------+------------
 t          | t
(1 row)

-- Differential vs seq scan across several patterns.
SET enable_seqscan = off;
SET
SELECT count(*) AS idx_exact FROM pbuild_t WHERE body %~~ tre_pattern('error42', 0);
 idx_exact 
-----------
       200
(1 row)

SELECT count(*) AS idx_token FROM pbuild_t WHERE body %~~ tre_pattern('token7', 0);
 idx_token 
-----------
      1538
(1 row)

SET enable_indexscan = off;
SET
SET enable_bitmapscan = off;
SET
SELECT count(*) AS seq_exact FROM pbuild_t WHERE body %~~ tre_pattern('error42', 0);
 seq_exact 
-----------
       200
(1 row)

SELECT count(*) AS seq_token FROM pbuild_t WHERE body %~~ tre_pattern('token7', 0);
 seq_token 
-----------
      1538
(1 row)

RESET enable_seqscan;
RESET
RESET enable_indexscan;
RESET
RESET enable_bitmapscan;
RESET
-- A serial build of the same data must answer identically.
SET pg_tre.enable_parallel_build = off;
SET
CREATE INDEX pbuild_ser ON pbuild_t USING tre (body);
CREATE INDEX
SET enable_seqscan = off;
SET
SELECT count(*) AS ser_exact FROM pbuild_t WHERE body %~~ tre_pattern('error42', 0);
 ser_exact 
-----------
       200
(1 row)

RESET enable_seqscan;
RESET
DROP TABLE pbuild_t CASCADE;
DROP TABLE