Merge branch 'master' into properly-display-or-hide-tenant-info

Author: AndrewChubatiuk

docs/victorialogs/CHANGELOG.md

@@ -20,6 +20,8 @@ according to [these docs](https://docs.victoriametrics.com/victorialogs/quicksta
 
 * FEATURE: [web UI](https://docs.victoriametrics.com/victorialogs/querying/#web-ui): set proper tenant information, when `AccountID` and `ProjectID` headers are set by a proxy or completely hide it in UI if `-select.disableTenantResponseHeaders` flag is set. See [#656](https://github.com/VictoriaMetrics/VictoriaLogs/issues/656)
 
+* BUGFIX: [`/select/logsql/query` endpoint](https://docs.victoriametrics.com/victorialogs/querying/#querying-logs): properly optimize the query execution when the `limit` query arg is set, while the `offset` query arg isn't set. It wasn't addressed properly in [v1.33.0](#v1330). See [#620](https://github.com/VictoriaMetrics/VictoriaLogs/issues/620).
+
 ## [v1.33.0](https://github.com/VictoriaMetrics/VictoriaLogs/releases/tag/v1.33.0)
 
 Released at 2025-09-10

lib/logstorage/net_query_runner_test.go

@@ -84,4 +84,9 @@ func TestSplitQueryToRemoteAndLocal(t *testing.T) {
 	f(`foo | unpack_syslog`, `foo | unpack_syslog`, ``)
 	f(`foo | unpack_words`, `foo | unpack_words`, ``)
 	f(`foo | unroll by (x)`, `foo | unroll by (x)`, ``)
+
+	// Special cases with 'offset 0'
+	// See https://github.com/VictoriaMetrics/VictoriaLogs/issues/620#issuecomment-3276624504
+	f(`foo | offset 0`, `foo`, ``)
+	f(`foo | offset 0 | limit 10`, `foo | limit 10`, `limit 10`)
 }

lib/logstorage/parser.go

@@ -790,7 +790,7 @@ func (q *Query) AddPipeOffsetLimit(offset, limit uint64) {
 	q.mustAppendPipe(limitStr)
 
 	// optimize the query, so the `offset` and `limit` pipes could be joined with the preceding `sort` pipe.
-	q.pipes = optimizeSortOffsetLimitPipes(q.pipes)
+	q.pipes = optimizeOffsetLimitPipes(q.pipes)
 }
 
 func (q *Query) mustAppendPipe(s string) {
@@ -807,7 +807,7 @@ func (q *Query) optimize() {
 }
 
 func (q *Query) optimizeNoSubqueries() {
-	q.pipes = optimizeSortOffsetLimitPipes(q.pipes)
+	q.pipes = optimizeOffsetLimitPipes(q.pipes)
 	q.pipes = optimizeUniqLimitPipes(q.pipes)
 	q.pipes = optimizeFilterPipes(q.pipes)
 
@@ -1323,15 +1323,28 @@ func removeStarFilters(f filter) filter {
 	return f
 }
 
-func optimizeSortOffsetLimitPipes(pipes []pipe) []pipe {
+func optimizeOffsetLimitPipes(pipes []pipe) []pipe {
 	for {
 		pipesLen := len(pipes)
 		pipes = optimizeSortOffsetPipes(pipes)
 		pipes = optimizeSortLimitPipes(pipes)
 		if len(pipes) == pipesLen {
-			return pipes
+			break
 		}
 	}
+
+	// Remove `offset 0` pipes.
+	i := 0
+	for i < len(pipes) {
+		po, ok := pipes[i].(*pipeOffset)
+		if !ok || po.offset != 0 {
+			i++
+			continue
+		}
+		pipes = append(pipes[:i], pipes[i+1:]...)
+	}
+
+	return pipes
 }
 
 func optimizeSortOffsetPipes(pipes []pipe) []pipe {

lib/logstorage/parser_test.go

@@ -355,7 +355,7 @@ func TestQuery_AddTimeFilter_StepPropagation(t *testing.T) {
 	})
 }
 
-func TestParseQuery_OptimizeSortOffsetLimitPipes(t *testing.T) {
+func TestParseQuery_OptimizeOffsetLimitPipes(t *testing.T) {
 	f := func(s, resultExpected string) {
 		t.Helper()
 
@@ -385,6 +385,11 @@ func TestParseQuery_OptimizeSortOffsetLimitPipes(t *testing.T) {
 	f(`* | sort by (x) | limit 30 | limit 20 | offset 4`, `* | sort by (x) offset 4 limit 16`)
 	f(`* | sort by (x) | limit 30 | limit 20 | offset 4 | offset 5`, `* | sort by (x) offset 9 limit 11`)
 	f(`* | sort by (x) | limit 30 | limit 20 | offset 4 | offset 5 | fields x`, `* | sort by (x) offset 9 limit 11 | fields x`)
+
+	// Verify the case without 'sort' pipe and with 'offset 0' pipes.
+	// See https://github.com/VictoriaMetrics/VictoriaLogs/issues/620#issuecomment-3276624504
+	f(`* | offset 0`, `*`)
+	f(`* | offset 0 | limit 10`, `* | limit 10`)
 }
 
 func TestParseQuery_OptimizeStarFilters(t *testing.T) {

lib/logstorage/pipe_offset.go

@@ -19,6 +19,10 @@ func (po *pipeOffset) String() string {
 }
 
 func (po *pipeOffset) splitToRemoteAndLocal(_ int64) (pipe, []pipe) {
+	if po.offset == 0 {
+		// Special case - `offset 0` is safe to push to the remote side.
+		return po, nil
+	}
 	return nil, []pipe{po}
 }