worker_spi: Rename custom wait event to "WorkerSpiMain"

This naming is more consistent with all the other user-facing wait event
strings.  Other in-core modules will use the same naming convention, so
let's be consistent here as well.

Extracted from a larger patch by the same author.

Author: Masahiro Ikeda
Discussion: https://postgr.es/m/197bce267fa691a0ac62c86c4ab904c4@oss.nttdata.com

Author: michaelpq

doc/src/sgml/xfunc.sgml

@@ -3472,9 +3472,9 @@ uint32 WaitEventExtensionNew(const char *wait_event_name)
 <screen>
 =# SELECT wait_event_type, wait_event FROM pg_stat_activity
      WHERE backend_type ~ 'worker_spi';
- wait_event_type |   wait_event
------------------+-----------------
- Extension       | worker_spi_main
+ wait_event_type |  wait_event
+-----------------+---------------
+ Extension       | WorkerSpiMain
 (1 row)
 </screen>
     </para>

src/test/modules/worker_spi/t/001_worker_spi.pl

@@ -43,15 +43,15 @@
 $result = $node->poll_query_until(
 	'postgres',
 	qq[SELECT wait_event FROM pg_stat_activity WHERE backend_type ~ 'worker_spi';],
-	qq[worker_spi_main]);
+	qq[WorkerSpiMain]);
 is($result, 1,
-	'dynamic bgworker has reported "worker_spi_main" as wait event');
+	'dynamic bgworker has reported "WorkerSpiMain" as wait event');
 
 # Check the wait event used by the dynamic bgworker appears in pg_wait_events
 $result = $node->safe_psql('postgres',
-	q[SELECT count(*) > 0 from pg_wait_events where type = 'Extension' and name = 'worker_spi_main';]
+	q[SELECT count(*) > 0 from pg_wait_events where type = 'Extension' and name = 'WorkerSpiMain';]
 );
-is($result, 't', '"worker_spi_main" is reported in pg_wait_events');
+is($result, 't', '"WorkerSpiMain" is reported in pg_wait_events');
 
 note "testing bgworkers loaded with shared_preload_libraries";
 
@@ -74,7 +74,7 @@
 		'mydb',
 		qq[SELECT datname, count(datname), wait_event FROM pg_stat_activity
             WHERE backend_type = 'worker_spi' GROUP BY datname, wait_event;],
-		'mydb|3|worker_spi_main'),
+		'mydb|3|WorkerSpiMain'),
 	'bgworkers all launched'
 ) or die "Timed out while waiting for bgworkers to be launched";
 
@@ -89,7 +89,7 @@
 		qq[SELECT datname, count(datname), wait_event FROM pg_stat_activity
             WHERE backend_type = 'worker_spi dynamic' AND
             pid IN ($worker1_pid, $worker2_pid) GROUP BY datname, wait_event;],
-		'mydb|2|worker_spi_main'),
+		'mydb|2|WorkerSpiMain'),
 	'dynamic bgworkers all launched'
 ) or die "Timed out while waiting for dynamic bgworkers to be launched";
 

src/test/modules/worker_spi/worker_spi.c

@@ -194,7 +194,7 @@ worker_spi_main(Datum main_arg)
 
 		/* First time, allocate or get the custom wait event */
 		if (worker_spi_wait_event_main == 0)
-			worker_spi_wait_event_main = WaitEventExtensionNew("worker_spi_main");
+			worker_spi_wait_event_main = WaitEventExtensionNew("WorkerSpiMain");
 
 		/*
 		 * Background workers mustn't call usleep() or any direct equivalent: