From 85a0781334a204c15c9c6ea9d3e6c75334c2beb6 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 14 Apr 2017 17:51:25 -0400
Subject: [PATCH] Use one transaction while reading postgres.bki, not one per
line.
AFAICT, the only actual benefit of closing a bootstrap transaction
is to reclaim transient memory. We can do that a lot more cheaply
by just doing a MemoryContextReset on a suitable context. This
gets the runtime of the "bootstrap" phase of initdb down to the
point where, at least by eyeball, it's quite negligible compared
to the rest of the phases. Per discussion with Andres Freund.
Discussion: https://postgr.es/m/9244.1492106743@sss.pgh.pa.us
---
src/backend/bootstrap/bootparse.y | 18 +++++++++++++-----
src/backend/bootstrap/bootstrap.c | 3 +++
2 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/src/backend/bootstrap/bootparse.y b/src/backend/bootstrap/bootparse.y
index 867f77076d0..de3695c7e05 100644
--- a/src/backend/bootstrap/bootparse.y
+++ b/src/backend/bootstrap/bootparse.y
@@ -22,7 +22,6 @@
#include "access/htup.h"
#include "access/itup.h"
#include "access/tupdesc.h"
-#include "access/xact.h"
#include "bootstrap/bootstrap.h"
#include "catalog/catalog.h"
#include "catalog/heap.h"
@@ -49,6 +48,7 @@
#include "storage/off.h"
#include "storage/smgr.h"
#include "tcop/dest.h"
+#include "utils/memutils.h"
#include "utils/rel.h"
@@ -63,19 +63,27 @@
#define YYMALLOC palloc
#define YYFREE pfree
+static MemoryContext per_line_ctx = NULL;
+
static void
do_start(void)
{
- StartTransactionCommand();
- elog(DEBUG4, "start transaction");
+ Assert(CurrentMemoryContext == CurTransactionContext);
+ /* First time through, create the per-line working context */
+ if (per_line_ctx == NULL)
+ per_line_ctx = AllocSetContextCreate(CurTransactionContext,
+ "bootstrap per-line processing",
+ ALLOCSET_DEFAULT_SIZES);
+ MemoryContextSwitchTo(per_line_ctx);
}
static void
do_end(void)
{
- CommitTransactionCommand();
- elog(DEBUG4, "commit transaction");
+ /* Reclaim memory allocated while processing this line */
+ MemoryContextSwitchTo(CurTransactionContext);
+ MemoryContextReset(per_line_ctx);
CHECK_FOR_INTERRUPTS(); /* allow SIGINT to kill bootstrap run */
if (isatty(0))
{
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 46c207c86c8..4c28b2b821a 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -18,6 +18,7 @@
#include <signal.h>
#include "access/htup_details.h"
+#include "access/xact.h"
#include "bootstrap/bootstrap.h"
#include "catalog/index.h"
#include "catalog/pg_collation.h"
@@ -496,7 +497,9 @@ BootstrapModeMain(void)
/*
* Process bootstrap input.
*/
+ StartTransactionCommand();
boot_yyparse();
+ CommitTransactionCommand();
/*
* We should now know about all mapped relations, so it's okay to write
--
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