The image shows the process an application uses to optimistically control concurrency. There are five icons, four of which are connected by four arrows.

• A database icon, labeled "Database", is at the source end of an arrow labeled "1 GET", whose destination end is a JSON-document icon that shows a magnified document portion with the text "etag : E43B9...".

• That JSON-document icon is at the source end of an arrow labeled "2 Change", whose destination end is an identical JSON-document icon.

• Alongside the two JSON-document icons and the arrow labeled "2 Change" is an application icon, labeled "Application". (It is not connected to any arrow.)

• The second JSON-document icon is at the source end of an arrow labeled "3 PUT", whose destination is an octagonal STOP-sign icon.

• The STOP-sign icon has the text "STOP if ETAG mismatch". It is at the source end of an unlabeled arrow, whose destination is the database icon.