Refactor some repetitive SLRU code

Functions to bootstrap and zero pages in various SLRU callers were
fairly duplicative.  We can slash almost two hundred lines with a couple
of simple helpers:

 - SimpleLruZeroAndWritePage: Does the equivalent of SimpleLruZeroPage
   followed by flushing the page to disk
 - XLogSimpleInsertInt64: Does a XLogBeginInsert followed by XLogInsert
   of a trivial record whose data is just an int64.

Author: Evgeny Voropaev <evgeny.voropaev@tantorlabs.com>
Reviewed by: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed by: Aleksander Alekseev <aleksander@timescale.com>
Discussion: https://www.postgresql.org/message-id/flat/97820ce8-a1cd-407f-a02b-47368fadb14b%40tantorlabs.com

1 files changed, 12 insertions, 0 deletions

diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c
index 5ee9d0b028e..c7571429e8e 100644
--- a/src/backend/access/transam/xloginsert.c
+++ b/src/backend/access/transam/xloginsert.c
@@ -530,6 +530,18 @@ XLogInsert(RmgrId rmid, uint8 info)
 }
 
 /*
+ * Simple wrapper to XLogInsert to insert a WAL record with elementary
+ * contents (only an int64 is supported as value currently).
+ */
+XLogRecPtr
+XLogSimpleInsertInt64(RmgrId rmid, uint8 info, int64 value)
+{
+	XLogBeginInsert();
+	XLogRegisterData(&value, sizeof(value));
+	return XLogInsert(rmid, info);
+}
+
+/*
  * Assemble a WAL record from the registered data and buffers into an
  * XLogRecData chain, ready for insertion with XLogInsertRecord().
  *