Remove redundant memset(0) calls for page init of some index AMs

michaelpq · michaelpq · commit 4c0239cb7a77 · 2021-04-07T14:35:26.000+09:00
Bloom, GIN, GiST and SP-GiST rely on PageInit() to initialize the contents of a page, and this routine fills entirely a page with zeros for a size of BLCKSZ, including the special space. Those index AMs have been using an extra memset() call to fill with zeros the special page space, or even the whole page, which is not necessary as PageInit() already does this work, so let's remove them. GiST was not doing this extra call, but has commented out a system call that did so since 6236991. While on it, remove one MAXALIGN() for SP-GiST as PageInit() takes care of that. This makes the whole page initialization logic more consistent across all index AMs. Author: Bharath Rupireddy Reviewed-by: Vignesh C, Mahendra Singh Thalor Discussion: https://postgr.es/m/CALj2ACViOo2qyaPT7krWm4LRyRTw9kOXt+g6PfNmYuGA=YHj9A@mail.gmail.com
diff --git a/contrib/bloom/blinsert.c b/contrib/bloom/blinsert.c
@@ -63,7 +63,6 @@ flushCachedPage(Relation index, BloomBuildState *buildstate)
 static void
 initCachedPage(BloomBuildState *buildstate)
 {
-	memset(buildstate->data.data, 0, BLCKSZ);
 	BloomInitPage(buildstate->data.data, 0);
 	buildstate->count = 0;
 }
diff --git a/contrib/bloom/blutils.c b/contrib/bloom/blutils.c
@@ -411,7 +411,6 @@ BloomInitPage(Page page, uint16 flags)
 	PageInit(page, BLCKSZ, sizeof(BloomPageOpaqueData));
 
 	opaque = BloomPageGetOpaque(page);
-	memset(opaque, 0, sizeof(BloomPageOpaqueData));
 	opaque->flags = flags;
 	opaque->bloom_page_id = BLOOM_PAGE_ID;
 }
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
@@ -348,7 +348,6 @@ GinInitPage(Page page, uint32 f, Size pageSize)
 	PageInit(page, pageSize, sizeof(GinPageOpaqueData));
 
 	opaque = GinPageGetOpaque(page);
-	memset(opaque, 0, sizeof(GinPageOpaqueData));
 	opaque->flags = f;
 	opaque->rightlink = InvalidBlockNumber;
 }
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
@@ -761,8 +761,6 @@ gistinitpage(Page page, uint32 f)
 	PageInit(page, pageSize, sizeof(GISTPageOpaqueData));
 
 	opaque = GistPageGetOpaque(page);
-	/* page was already zeroed by PageInit, so this is not needed: */
-	/* memset(&(opaque->nsn), 0, sizeof(GistNSN)); */
 	opaque->rightlink = InvalidBlockNumber;
 	opaque->flags = f;
 	opaque->gist_page_id = GIST_PAGE_ID;
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
@@ -677,9 +677,8 @@ SpGistInitPage(Page page, uint16 f)
 {
 	SpGistPageOpaque opaque;
 
-	PageInit(page, BLCKSZ, MAXALIGN(sizeof(SpGistPageOpaqueData)));
+	PageInit(page, BLCKSZ, sizeof(SpGistPageOpaqueData));
 	opaque = SpGistPageGetOpaque(page);
-	memset(opaque, 0, sizeof(SpGistPageOpaqueData));
 	opaque->flags = f;
 	opaque->spgist_page_id = SPGIST_PAGE_ID;
 }

Original file line number	Diff line number	Diff line change
`@@ -63,7 +63,6 @@ flushCachedPage(Relation index, BloomBuildState *buildstate)`
`63`	`63`	`static void`
`64`	`64`	`initCachedPage(BloomBuildState *buildstate)`
`65`	`65`	`{`
`66`		`- memset(buildstate->data.data, 0, BLCKSZ);`
`67`	`66`	`BloomInitPage(buildstate->data.data, 0);`
`68`	`67`	`buildstate->count = 0;`
`69`	`68`	`}`
Original file line number	Diff line number	Diff line change
`@@ -411,7 +411,6 @@ BloomInitPage(Page page, uint16 flags)`
`411`	`411`	`PageInit(page, BLCKSZ, sizeof(BloomPageOpaqueData));`
`412`	`412`
`413`	`413`	`opaque = BloomPageGetOpaque(page);`
`414`		`- memset(opaque, 0, sizeof(BloomPageOpaqueData));`
`415`	`414`	`opaque->flags = flags;`
`416`	`415`	`opaque->bloom_page_id = BLOOM_PAGE_ID;`
`417`	`416`	`}`
Original file line number	Diff line number	Diff line change
`@@ -348,7 +348,6 @@ GinInitPage(Page page, uint32 f, Size pageSize)`
`348`	`348`	`PageInit(page, pageSize, sizeof(GinPageOpaqueData));`
`349`	`349`
`350`	`350`	`opaque = GinPageGetOpaque(page);`
`351`		`- memset(opaque, 0, sizeof(GinPageOpaqueData));`
`352`	`351`	`opaque->flags = f;`
`353`	`352`	`opaque->rightlink = InvalidBlockNumber;`
`354`	`353`	`}`
Original file line number	Diff line number	Diff line change
`@@ -677,9 +677,8 @@ SpGistInitPage(Page page, uint16 f)`
`677`	`677`	`{`
`678`	`678`	`SpGistPageOpaque opaque;`
`679`	`679`
`680`		`- PageInit(page, BLCKSZ, MAXALIGN(sizeof(SpGistPageOpaqueData)));`
	`680`	`+ PageInit(page, BLCKSZ, sizeof(SpGistPageOpaqueData));`
`681`	`681`	`opaque = SpGistPageGetOpaque(page);`
`682`		`- memset(opaque, 0, sizeof(SpGistPageOpaqueData));`
`683`	`682`	`opaque->flags = f;`
`684`	`683`	`opaque->spgist_page_id = SPGIST_PAGE_ID;`
`685`	`684`	`}`