v2-0001-Elimination-of-the-repetitive-code-at-the-SLRU-bo.patch

From a5a29cdbb37834bfcd23cd22db90a78a7db43d18 Mon Sep 17 00:00:00 2001
From: Evgeny Voropaev <evorop@gmail.com>
Date: Fri, 14 Feb 2025 14:03:01 +0800
Subject: [PATCH v2] Elimination of the repetitive code at the SLRU bootstrap
 functions.

The functions bootstrapping SLRU pages used to have a lot of repetitive code. The new
realized function BootStrapSlruPage has moved duplicating code into the
single place and eliminated code repetitions.

Author: Evgeny Voropaev <evgeny.voropaev@tantorlabs.com> <evorop@gmail.com>
---
 src/backend/access/transam/clog.c      | 27 +------------
 src/backend/access/transam/commit_ts.c | 24 +-----------
 src/backend/access/transam/multixact.c | 54 ++------------------------
 src/backend/access/transam/slru.c      | 35 +++++++++++++++++
 src/backend/access/transam/subtrans.c  | 28 ++++++-------
 src/include/access/slru.h              |  1 +
 6 files changed, 55 insertions(+), 114 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 0d556c00b8c..5ae684da6af 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -832,19 +832,7 @@ check_transaction_buffers(int *newval, void **extra, GucSource source)
 void
 BootStrapCLOG(void)
 {
-	int			slotno;
-	LWLock	   *lock = SimpleLruGetBankLock(XactCtl, 0);
-
-	LWLockAcquire(lock, LW_EXCLUSIVE);
-
-	/* Create and zero the first page of the commit log */
-	slotno = ZeroCLOGPage(0, false);
-
-	/* Make sure it's written out */
-	SimpleLruWritePage(XactCtl, slotno);
-	Assert(!XactCtl->shared->page_dirty[slotno]);
-
-	LWLockRelease(lock);
+	BootStrapSlruPage(XactCtl, 0, ZeroCLOGPage);
 }
 
 /*
@@ -1114,19 +1102,8 @@ clog_redo(XLogReaderState *record)
 	if (info == CLOG_ZEROPAGE)
 	{
 		int64		pageno;
-		int			slotno;
-		LWLock	   *lock;
-
 		memcpy(&pageno, XLogRecGetData(record), sizeof(pageno));
-
-		lock = SimpleLruGetBankLock(XactCtl, pageno);
-		LWLockAcquire(lock, LW_EXCLUSIVE);
-
-		slotno = ZeroCLOGPage(pageno, false);
-		SimpleLruWritePage(XactCtl, slotno);
-		Assert(!XactCtl->shared->page_dirty[slotno]);
-
-		LWLockRelease(lock);
+		BootStrapSlruPage(XactCtl, pageno, ZeroCLOGPage);
 	}
 	else if (info == CLOG_TRUNCATE)
 	{
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 95049acd0b5..54600f1b69c 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -747,16 +747,7 @@ ActivateCommitTs(void)
 
 	/* Create the current segment file, if necessary */
 	if (!SimpleLruDoesPhysicalPageExist(CommitTsCtl, pageno))
-	{
-		LWLock	   *lock = SimpleLruGetBankLock(CommitTsCtl, pageno);
-		int			slotno;
-
-		LWLockAcquire(lock, LW_EXCLUSIVE);
-		slotno = ZeroCommitTsPage(pageno, false);
-		SimpleLruWritePage(CommitTsCtl, slotno);
-		Assert(!CommitTsCtl->shared->page_dirty[slotno]);
-		LWLockRelease(lock);
-	}
+		BootStrapSlruPage(CommitTsCtl, pageno, ZeroCommitTsPage);
 
 	/* Change the activation status in shared memory. */
 	LWLockAcquire(CommitTsLock, LW_EXCLUSIVE);
@@ -1023,19 +1014,8 @@ commit_ts_redo(XLogReaderState *record)
 	if (info == COMMIT_TS_ZEROPAGE)
 	{
 		int64		pageno;
-		int			slotno;
-		LWLock	   *lock;
-
 		memcpy(&pageno, XLogRecGetData(record), sizeof(pageno));
-
-		lock = SimpleLruGetBankLock(CommitTsCtl, pageno);
-		LWLockAcquire(lock, LW_EXCLUSIVE);
-
-		slotno = ZeroCommitTsPage(pageno, false);
-		SimpleLruWritePage(CommitTsCtl, slotno);
-		Assert(!CommitTsCtl->shared->page_dirty[slotno]);
-
-		LWLockRelease(lock);
+		BootStrapSlruPage(CommitTsCtl, pageno, ZeroCommitTsPage);
 	}
 	else if (info == COMMIT_TS_TRUNCATE)
 	{
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 27ccdf9500f..30cc47021f7 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -2033,32 +2033,8 @@ check_multixact_member_buffers(int *newval, void **extra, GucSource source)
 void
 BootStrapMultiXact(void)
 {
-	int			slotno;
-	LWLock	   *lock;
-
-	lock = SimpleLruGetBankLock(MultiXactOffsetCtl, 0);
-	LWLockAcquire(lock, LW_EXCLUSIVE);
-
-	/* Create and zero the first page of the offsets log */
-	slotno = ZeroMultiXactOffsetPage(0, false);
-
-	/* Make sure it's written out */
-	SimpleLruWritePage(MultiXactOffsetCtl, slotno);
-	Assert(!MultiXactOffsetCtl->shared->page_dirty[slotno]);
-
-	LWLockRelease(lock);
-
-	lock = SimpleLruGetBankLock(MultiXactMemberCtl, 0);
-	LWLockAcquire(lock, LW_EXCLUSIVE);
-
-	/* Create and zero the first page of the members log */
-	slotno = ZeroMultiXactMemberPage(0, false);
-
-	/* Make sure it's written out */
-	SimpleLruWritePage(MultiXactMemberCtl, slotno);
-	Assert(!MultiXactMemberCtl->shared->page_dirty[slotno]);
-
-	LWLockRelease(lock);
+	BootStrapSlruPage(MultiXactOffsetCtl, 0, ZeroMultiXactOffsetPage);
+	BootStrapSlruPage(MultiXactMemberCtl, 0, ZeroMultiXactMemberPage);
 }
 
 /*
@@ -3401,36 +3377,14 @@ multixact_redo(XLogReaderState *record)
 	if (info == XLOG_MULTIXACT_ZERO_OFF_PAGE)
 	{
 		int64		pageno;
-		int			slotno;
-		LWLock	   *lock;
-
 		memcpy(&pageno, XLogRecGetData(record), sizeof(pageno));
-
-		lock = SimpleLruGetBankLock(MultiXactOffsetCtl, pageno);
-		LWLockAcquire(lock, LW_EXCLUSIVE);
-
-		slotno = ZeroMultiXactOffsetPage(pageno, false);
-		SimpleLruWritePage(MultiXactOffsetCtl, slotno);
-		Assert(!MultiXactOffsetCtl->shared->page_dirty[slotno]);
-
-		LWLockRelease(lock);
+		BootStrapSlruPage(MultiXactOffsetCtl, pageno, ZeroMultiXactOffsetPage);
 	}
 	else if (info == XLOG_MULTIXACT_ZERO_MEM_PAGE)
 	{
 		int64		pageno;
-		int			slotno;
-		LWLock	   *lock;
-
 		memcpy(&pageno, XLogRecGetData(record), sizeof(pageno));
-
-		lock = SimpleLruGetBankLock(MultiXactMemberCtl, pageno);
-		LWLockAcquire(lock, LW_EXCLUSIVE);
-
-		slotno = ZeroMultiXactMemberPage(pageno, false);
-		SimpleLruWritePage(MultiXactMemberCtl, slotno);
-		Assert(!MultiXactMemberCtl->shared->page_dirty[slotno]);
-
-		LWLockRelease(lock);
+		BootStrapSlruPage(MultiXactMemberCtl, pageno, ZeroMultiXactMemberPage);
 	}
 	else if (info == XLOG_MULTIXACT_CREATE_ID)
 	{
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index 9ce628e62a5..fd332fd4c64 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -1850,3 +1850,38 @@ SlruSyncFileTag(SlruCtl ctl, const FileTag *ftag, char *path)
 	errno = save_errno;
 	return result;
 }
+
+/*
+ * BootStrapSlruPage is a workhorse for functions bootstraping
+ *  SLRU pages, including:
+ *		BootStrapMultiXact,
+ *		BootStrapCLOG,
+ *		ActivateCommitTs,
+ *		multixact_redo,
+ *		commit_ts_redo.
+ *
+ * It performs all of the rut such as acquiring a lock, zeroing,
+ * ensuring that a bootstrapped page is written out, and releasing the lock.
+ *
+ * A caller has to provide a proper zerofunc appropriate for the type of 
+ * the page.
+ *
+ */
+void
+BootStrapSlruPage(SlruCtl ctl, int64 pageno, int(*zerofunc)(int64, bool) )
+{
+	int			slotno;
+	LWLock	   *lock;
+
+	lock = SimpleLruGetBankLock(ctl, pageno);
+	LWLockAcquire(lock, LW_EXCLUSIVE);
+
+	/* Create and zero the page*/
+	slotno = (*zerofunc)(pageno, false);
+
+	/* Make sure it's written out */
+	SimpleLruWritePage(ctl, slotno);
+	Assert(!ctl->shared->page_dirty[slotno]);
+
+	LWLockRelease(lock);
+}
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index 15153618fad..ec63c823d66 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -74,7 +74,7 @@ static SlruCtlData SubTransCtlData;
 #define SubTransCtl  (&SubTransCtlData)
 
 
-static int	ZeroSUBTRANSPage(int64 pageno);
+static int	ZeroSUBTRANSPage(int64 pageno, bool unused);
 static bool SubTransPagePrecedes(int64 page1, int64 page2);
 
 
@@ -269,19 +269,7 @@ check_subtrans_buffers(int *newval, void **extra, GucSource source)
 void
 BootStrapSUBTRANS(void)
 {
-	int			slotno;
-	LWLock	   *lock = SimpleLruGetBankLock(SubTransCtl, 0);
-
-	LWLockAcquire(lock, LW_EXCLUSIVE);
-
-	/* Create and zero the first page of the subtrans log */
-	slotno = ZeroSUBTRANSPage(0);
-
-	/* Make sure it's written out */
-	SimpleLruWritePage(SubTransCtl, slotno);
-	Assert(!SubTransCtl->shared->page_dirty[slotno]);
-
-	LWLockRelease(lock);
+	BootStrapSlruPage(SubTransCtl, 0, ZeroSUBTRANSPage);
 }
 
 /*
@@ -291,10 +279,16 @@ BootStrapSUBTRANS(void)
  * The slot number of the new page is returned.
  *
  * Control lock must be held at entry, and will be held at exit.
+ *
+ * "bool unused" is a parameter required to provide matching of the
+ * ZeroSUBTRANSPage function to the zerofunc function prototype
+ * used by BootStrapSlruPage.
  */
 static int
-ZeroSUBTRANSPage(int64 pageno)
+ZeroSUBTRANSPage(int64 pageno, bool unused)
 {
+	(void)unused; /* Supress compiler warning */
+
 	return SimpleLruZeroPage(SubTransCtl, pageno);
 }
 
@@ -335,7 +329,7 @@ StartupSUBTRANS(TransactionId oldestActiveXID)
 			prevlock = lock;
 		}
 
-		(void) ZeroSUBTRANSPage(startPage);
+		(void) ZeroSUBTRANSPage(startPage, false);
 		if (startPage == endPage)
 			break;
 
@@ -395,7 +389,7 @@ ExtendSUBTRANS(TransactionId newestXact)
 	LWLockAcquire(lock, LW_EXCLUSIVE);
 
 	/* Zero the page */
-	ZeroSUBTRANSPage(pageno);
+	ZeroSUBTRANSPage(pageno, false);
 
 	LWLockRelease(lock);
 }
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index e142800aab2..515986b4506 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -214,5 +214,6 @@ extern bool SlruScanDirCbReportPresence(SlruCtl ctl, char *filename,
 extern bool SlruScanDirCbDeleteAll(SlruCtl ctl, char *filename, int64 segpage,
 								   void *data);
 extern bool check_slru_buffers(const char *name, int *newval);
+extern void BootStrapSlruPage( SlruCtl ctl, int64 pageno, int(*zerofunc)(int64, bool) );
 
 #endif							/* SLRU_H */
-- 
2.47.1