Commitdf4eddb

committed

Fix GiST README's explanation of the NSN cross-check.

The text got the condition backwards, it's "NSN > LSN", not "NSN < LSN".While we're at it, expand it a little for clarity.Reviewed-by: Daniel GustafssonDiscussion:https://www.postgresql.org/message-id/4cb46e18-e688-524a-0f73-b1f03ed5d6ee@iki.fi

1 parent99d27e5 commitdf4eddbCopy full SHA for df4eddb

File tree

-4

lines changed

-4

lines changed

Lines changed: 4 additions & 4 deletions

Original file line number	Diff line number	Diff line change
`@@ -269,10 +269,10 @@ should be visited too. When split inserts the downlink to the parent, it`
`269`	`269`	`clears the F_FOLLOW_RIGHT flag in the child, and sets the NSN field in the`
`270`	`270`	`child page header to match the LSN of the insertion on the parent. If the`
`271`	`271`	`F_FOLLOW_RIGHT flag is not set, a scan compares the NSN on the child and the`
`272`		`-LSN it saw in the parent. IfNSN < LSN, the scan looked attheparent page`
`273`		`-beforethedownlink was inserted, so it should follow therightlink. Otherwise`
`274`		`-the scan saw the downlink intheparent page, and will/did follow that as`
`275`		`-usual.`
	`272`	`+LSN it saw in the parent. Ifthe child's NSN is greater thantheLSN seen on`
	`273`	`+the parent,thescan looked at the parent page before thedownlink was`
	`274`	`+inserted, so it should followtherightlink. Otherwise the scan saw the`
	`275`	`+downlink in the parent page, and will/did follow that asusual.`
`276`	`276`
`277`	`277`	`A scan can't normally see a page with the F_FOLLOW_RIGHT flag set, because`
`278`	`278`	`a page split keeps the child pages locked until the downlink has been inserted`

Comments

(0)