Remove unnecessary BufferGetPage() calls in fsm_vacuum_page().

tglsfdc · tglsfdc · commit 2b1759e2675f · 2018-03-29T12:44:19.000-04:00
Just noticed that these were quite redundant, since we're holding the
page address in a local variable anyway, and we have pin on the buffer
throughout.

Also improve a comment.
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
@@ -866,20 +866,21 @@ fsm_vacuum_page(Relation rel, FSMAddress addr,
 			if (fsm_get_avail(page, slot) != child_avail)
 			{
 				LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
-				fsm_set_avail(BufferGetPage(buf), slot, child_avail);
+				fsm_set_avail(page, slot, child_avail);
 				MarkBufferDirtyHint(buf, false);
 				LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 			}
 		}
 	}
 
 	/* Now get the maximum value on the page, to return to caller */
-	max_avail = fsm_get_max_avail(BufferGetPage(buf));
+	max_avail = fsm_get_max_avail(page);
 
 	/*
 	 * Reset the next slot pointer. This encourages the use of low-numbered
 	 * pages, increasing the chances that a later vacuum can truncate the
-	 * relation.
+	 * relation.  We don't bother with a lock here, nor with marking the page
+	 * dirty if it wasn't already, since this is just a hint.
 	 */
 	((FSMPage) PageGetContents(page))->fp_next_slot = 0;
 

Original file line number	Diff line number	Diff line change
`@@ -866,20 +866,21 @@ fsm_vacuum_page(Relation rel, FSMAddress addr,`
`866`	`866`	`if (fsm_get_avail(page, slot) != child_avail)`
`867`	`867`	`{`
`868`	`868`	`LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);`
`869`		`- fsm_set_avail(BufferGetPage(buf), slot, child_avail);`
	`869`	`+ fsm_set_avail(page, slot, child_avail);`
`870`	`870`	`MarkBufferDirtyHint(buf, false);`
`871`	`871`	`LockBuffer(buf, BUFFER_LOCK_UNLOCK);`
`872`	`872`	`}`
`873`	`873`	`}`
`874`	`874`	`}`
`875`	`875`
`876`	`876`	`/* Now get the maximum value on the page, to return to caller */`
`877`		`- max_avail = fsm_get_max_avail(BufferGetPage(buf));`
	`877`	`+ max_avail = fsm_get_max_avail(page);`
`878`	`878`
`879`	`879`	`/*`
`880`	`880`	`* Reset the next slot pointer. This encourages the use of low-numbered`
`881`	`881`	`* pages, increasing the chances that a later vacuum can truncate the`
`882`		`- * relation.`
	`882`	`+ * relation. We don't bother with a lock here, nor with marking the page`
	`883`	`+ * dirty if it wasn't already, since this is just a hint.`
`883`	`884`	`*/`
`884`	`885`	`((FSMPage) PageGetContents(page))->fp_next_slot = 0;`
`885`	`886`