[+] add ManyTasks.sql sample showing enhanced reporting features

Author: pashagolub

samples/ManyChains.sql

@@ -0,0 +1,9 @@
+SELECT timetable.add_job(
+    job_name            => 'HelloWorld' || g.i,
+    job_schedule        => '* * * * *',
+    job_kind            => 'PROGRAM'::timetable.command_kind,
+    job_command         => 'bash',
+    job_parameters      => jsonb_build_array('-c', 'echo Hello World from ' || g.i),
+    job_live            => TRUE,
+    job_ignore_errors   => TRUE
+) as chain_id FROM generate_series(1, 500) AS g(i);

samples/ManyTasks.sql

@@ -1,9 +1,42 @@
-SELECT timetable.add_job(
-    job_name            => 'HelloWorld' || g.i,
-    job_schedule        => '* * * * *',
-    job_kind            => 'PROGRAM'::timetable.command_kind,
-    job_command         => 'bash',
-    job_parameters      => jsonb_build_array('-c', 'echo Hello World from ' || g.i),
-    job_live            => TRUE,
-    job_ignore_errors   => TRUE
-) as chain_id FROM generate_series(1, 500) AS g(i);
+WITH 
+    cte_chain (v_chain_id) AS ( -- let's create a new chain and add tasks to it later
+        INSERT INTO timetable.chain (chain_name, run_at, max_instances, live) 
+        VALUES ('many tasks', '* * * * *', 1, true)
+        RETURNING chain_id
+    ),
+    cte_tasks(v_task_id) AS ( -- now we'll add 500 tasks to the chain, some of them will fail
+        INSERT INTO timetable.task (chain_id, task_order, kind, command, ignore_error)
+        SELECT v_chain_id, g.s, 'SQL', 'SELECT 1.0 / round(random())::int4;', true
+        FROM cte_chain, generate_series(1, 500) AS g(s)
+        RETURNING task_id
+    ),
+    report_task(v_task_id) AS ( -- and the last reporting task will calculate the statistic
+        INSERT INTO timetable.task (chain_id, task_order, kind, command)
+        SELECT v_chain_id, 501, 'SQL', $CMD$DO
+$$
+DECLARE
+    s TEXT;
+BEGIN
+    WITH report AS (
+        SELECT 
+        count(*) FILTER (WHERE returncode = 0) AS success,
+        count(*) FILTER (WHERE returncode != 0) AS fail,
+        count(*) AS total
+        FROM timetable.execution_log 
+        WHERE chain_id = current_setting('pg_timetable.current_chain_id')::bigint
+          AND txid = txid_current()
+    )
+    SELECT 'Tasks executed:' || total || 
+         '; succeeded: ' || success || 
+         '; failed: ' || fail || 
+         '; ratio: ' || 100.0*success/GREATEST(total,1)
+    INTO s
+    FROM report;
+    RAISE NOTICE '%', s;
+END;
+$$
+$CMD$
+        FROM cte_chain
+        RETURNING task_id
+    )
+SELECT v_chain_id FROM cte_chain