wip

docs/VictoriaLogs/CHANGELOG.md

@@ -20,6 +20,7 @@ according to [these docs](https://docs.victoriametrics.com/victorialogs/quicksta
 ## tip
 
 * FEATURE: add `default` operator to [`math` pipe](https://docs.victoriametrics.com/victorialogs/logsql/#math-pipe). It allows setting `NaN` result to the given default value.
+* FEATURE: allow omitting result name in [`math` pipe](https://docs.victoriametrics.com/victorialogs/logsql/#math-pipe) expresions. In this case the result name is automatically set to string representation of the corresponding math expression. For example, `_time:5m | math duration / 1000` is equivalent to `_time:5m | math (duration / 1000) as "duration / 1000"`.
 * FEATURE: allow omitting result name in [`stats` pipe](https://docs.victoriametrics.com/victorialogs/logsql/#stats-pipe). In this case the result name is automatically set to string representation of the corresponding [stats function expression](https://docs.victoriametrics.com/victorialogs/logsql/#stats-pipe-functions). For example, `_time:5m | count(*)` is valid [LogsQL query](https://docs.victoriametrics.com/victorialogs/logsql/) now. It is equivalent to `_time:5m | stats count(*) as "count(*)"`.
 
 * BUGFIX: properly calculate the number of matching rows in `* | field_values x | stats count() rows` and in `* | unroll (x) | stats count() rows` queries.

docs/VictoriaLogs/LogsQL.md

@@ -1594,6 +1594,19 @@ See also:
 ### math pipe
 
 `| math ...` [pipe](#pipes) performs mathematical calculations over numeric values stored in [log fields](https://docs.victoriametrics.com/victorialogs/keyconcepts/#data-model).
+It has the following format:
+
+```
+| math
+  expr1 as resultName1,
+  ...
+  exprN as resultNameN
+```
+
+Where `exprX` is one of the supported math expressions mentioned below, while `resultNameX` is the name of the field to store the calculated result to.
+The `as` keyword is optional. The result name can be omitted. In this case the result is stored to a field with the name equal to string represenation
+of the corresponding math expression.
+
 For example, the following query divides `duration_msecs` field value by 1000, then rounds it to integer and stores the result in the `duration_secs` field:
 
 ```logsql
@@ -1621,15 +1634,6 @@ Every `argX` argument in every mathematical operation can contain one of the fol
 - Any [supported numeric value](#numeric-values). For example, `response_size_bytes / 1MiB`.
 - Another mathematical expression. Optionally, it may be put inside `(...)`. For example, `(a + b) * c`.
 
-Multiple distinct results can be calculated in a single `math ...` pipe - just separate them with `,`. For example, the following query calculates the error rate
-and the number of successful requests from `errors`, `warnings` and `requests` [log fields](https://docs.victoriametrics.com/victorialogs/keyconcepts/#data-model):
-
-```logsql
-_time:5m | math
-    (errors / requests) as error_rate,
-    (requests - (errors + warnings)) as success_requests
-```
-
 See also:
 
 - [`stats` pipe](#stats-pipe)

lib/logstorage/pipe_math.go

@@ -384,14 +384,20 @@ func parseMathEntry(lex *lexer) (*mathEntry, error) {
 		return nil, err
 	}
 
-	// skip optional 'as'
-	if lex.isKeyword("as") {
-		lex.nextToken()
-	}
+	resultField := ""
+	if lex.isKeyword(",", "|", ")", "") {
+		resultField = me.String()
+	} else {
+		if lex.isKeyword("as") {
+			// skip optional 'as'
+			lex.nextToken()
+		}
 
-	resultField, err := parseFieldName(lex)
-	if err != nil {
-		return nil, fmt.Errorf("cannot parse result name for [%s]: %w", me, err)
+		fieldName, err := parseFieldName(lex)
+		if err != nil {
+			return nil, fmt.Errorf("cannot parse result name for [%s]: %w", me, err)
+		}
+		resultField = fieldName
 	}
 
 	e := &mathEntry{

lib/logstorage/pipe_math_test.go

@@ -32,7 +32,6 @@ func TestParsePipeMathFailure(t *testing.T) {
 	}
 
 	f(`math`)
-	f(`math x`)
 	f(`math x as`)
 	f(`math abs() as x`)
 	f(`math abs(a, b) as x`)
@@ -64,7 +63,7 @@ func TestPipeMath(t *testing.T) {
 		},
 	})
 
-	f("math a / b default 10 as c", [][]Field{
+	f("math a / b default c", [][]Field{
 		{
 			{"a", "v1"},
 			{"b", "2"},
@@ -79,21 +78,32 @@ func TestPipeMath(t *testing.T) {
 			{"a", "3"},
 			{"b", "2"},
 		},
+		{
+			{"a", "3"},
+			{"b", "foo"},
+		},
 	}, [][]Field{
 		{
 			{"a", "v1"},
 			{"b", "2"},
-			{"c", "10"},
+			{"c", "3"},
+			{"a / b default c", "3"},
 		},
 		{
 			{"a", "0"},
 			{"b", "0"},
-			{"c", "10"},
+			{"c", "3"},
+			{"a / b default c", "3"},
 		},
 		{
 			{"a", "3"},
 			{"b", "2"},
-			{"c", "1.5"},
+			{"a / b default c", "1.5"},
+		},
+		{
+			{"a", "3"},
+			{"b", "foo"},
+			{"a / b default c", "NaN"},
 		},
 	})