In 4.0.6 and earlier, you could use $not operator with regular expression objects (i.e. /pattern/) but not with $regex operator expressions.

naughtyGitCat · naughtyGitCat · commit 8ce64fcaa359 · 2025-08-05T11:21:33.000+08:00
diff --git a/exporter/currentop_collector.go b/exporter/currentop_collector.go
@@ -84,7 +84,7 @@ func (d *currentopCollector) collect(ch chan<- prometheus.Metric) {
 		{Key: "op", Value: bson.D{{Key: "$ne", Value: ""}}},
 		{Key: "ns", Value: bson.D{
 			{Key: "$ne", Value: ""},
-			{Key: "$not", Value: bson.D{{Key: "$regex", Value: "^admin.*|^local.*"}}},
+			{Key: "$regex", Value: "/^(?!(admin|local)).*/"},
 		}},
 	}
 	res := client.Database("admin").RunCommand(d.ctx, cmd)

Original file line number	Diff line number	Diff line change
`@@ -84,7 +84,7 @@ func (d *currentopCollector) collect(ch chan<- prometheus.Metric) {`
`84`	`84`	`{Key: "op", Value: bson.D{{Key: "$ne", Value: ""}}},`
`85`	`85`	`{Key: "ns", Value: bson.D{`
`86`	`86`	`{Key: "$ne", Value: ""},`
`87`		`- {Key: "$not", Value: bson.D{{Key: "$regex", Value: "^admin.\|^local."}}},`
	`87`	`+ {Key: "$regex", Value: "/^(?!(admin\|local)).*/"},`
`88`	`88`	`}},`
`89`	`89`	`}`
`90`	`90`	`res := client.Database("admin").RunCommand(d.ctx, cmd)`