Add some basic tests for progress reporting of COPY

This tests some basic features for progress reporting of COPY, relying
on an INSERT trigger that gets fired when doing COPY FROM with a file or
stdin, checking for sizes, number of tuples processed, and number of
tuples excluded by a WHERE clause.

Author: Josef Šimánek, Matthias van de Meent
Reviewed-by: Michael Paquier, Justin Pryzby, Bharath Rupireddy, Tomas
Vondra
Discussion: https://postgr.es/m/CAEze2WiOcgdH4aQA8NtZq-4dgvnJzp8PohdeKchPkhMY-jWZXA@mail.gmail.com

src/test/regress/input/copy.source

@@ -201,3 +201,65 @@ select * from parted_copytest where b = 1;
 select * from parted_copytest where b = 2;
 
 drop table parted_copytest;
+
+--
+-- Progress reporting for COPY
+--
+create table tab_progress_reporting (
+	name text,
+	age int4,
+	location point,
+	salary int4,
+	manager name
+);
+
+-- Add a trigger to catch and print the contents of the catalog view
+-- pg_stat_progress_copy during data insertion.  This allows to test
+-- the validation of some progress reports for COPY FROM where the trigger
+-- would fire.
+create function notice_after_tab_progress_reporting() returns trigger AS
+$$
+declare report record;
+begin
+  -- The fields ignored here are the ones that may not remain
+  -- consistent across multiple runs.  The sizes reported may differ
+  -- across platforms, so just check if these are strictly positive.
+  with progress_data as (
+    select
+       relid::regclass::text as relname,
+       command,
+       type,
+       bytes_processed > 0 as has_bytes_processed,
+       bytes_total > 0 as has_bytes_total,
+       tuples_processed,
+       tuples_excluded
+      from pg_stat_progress_copy
+      where pid = pg_backend_pid())
+  select into report (to_jsonb(r)) as value
+    from progress_data r;
+
+  raise info 'progress: %', report.value::text;
+  return new;
+end;
+$$ language plpgsql;
+
+create trigger check_after_tab_progress_reporting
+	after insert on tab_progress_reporting
+	for each statement
+	execute function notice_after_tab_progress_reporting();
+
+-- Generate COPY FROM report with PIPE.
+copy tab_progress_reporting from stdin;
+sharon	25	(15,12)	1000	sam
+sam	30	(10,5)	2000	bill
+bill	20	(11,10)	1000	sharon
+\.
+
+-- Generate COPY FROM report with FILE, with some excluded tuples.
+truncate tab_progress_reporting;
+copy tab_progress_reporting from '@abs_srcdir@/data/emp.data'
+	where (salary < 2000);
+
+drop trigger check_after_tab_progress_reporting on tab_progress_reporting;
+drop function notice_after_tab_progress_reporting();
+drop table tab_progress_reporting;

src/test/regress/output/copy.source

@@ -165,3 +165,57 @@ select * from parted_copytest where b = 2;
 (1 row)
 
 drop table parted_copytest;
+--
+-- Progress reporting for COPY
+--
+create table tab_progress_reporting (
+	name text,
+	age int4,
+	location point,
+	salary int4,
+	manager name
+);
+-- Add a trigger to catch and print the contents of the catalog view
+-- pg_stat_progress_copy during data insertion.  This allows to test
+-- the validation of some progress reports for COPY FROM where the trigger
+-- would fire.
+create function notice_after_tab_progress_reporting() returns trigger AS
+$$
+declare report record;
+begin
+  -- The fields ignored here are the ones that may not remain
+  -- consistent across multiple runs.  The sizes reported may differ
+  -- across platforms, so just check if these are strictly positive.
+  with progress_data as (
+    select
+       relid::regclass::text as relname,
+       command,
+       type,
+       bytes_processed > 0 as has_bytes_processed,
+       bytes_total > 0 as has_bytes_total,
+       tuples_processed,
+       tuples_excluded
+      from pg_stat_progress_copy
+      where pid = pg_backend_pid())
+  select into report (to_jsonb(r)) as value
+    from progress_data r;
+
+  raise info 'progress: %', report.value::text;
+  return new;
+end;
+$$ language plpgsql;
+create trigger check_after_tab_progress_reporting
+	after insert on tab_progress_reporting
+	for each statement
+	execute function notice_after_tab_progress_reporting();
+-- Generate COPY FROM report with PIPE.
+copy tab_progress_reporting from stdin;
+INFO:  progress: {"type": "PIPE", "command": "COPY FROM", "relname": "tab_progress_reporting", "has_bytes_total": false, "tuples_excluded": 0, "tuples_processed": 3, "has_bytes_processed": true}
+-- Generate COPY FROM report with FILE, with some excluded tuples.
+truncate tab_progress_reporting;
+copy tab_progress_reporting from '@abs_srcdir@/data/emp.data'
+	where (salary < 2000);
+INFO:  progress: {"type": "FILE", "command": "COPY FROM", "relname": "tab_progress_reporting", "has_bytes_total": true, "tuples_excluded": 1, "tuples_processed": 2, "has_bytes_processed": true}
+drop trigger check_after_tab_progress_reporting on tab_progress_reporting;
+drop function notice_after_tab_progress_reporting();
+drop table tab_progress_reporting;