From a080c9e4e5aa4c5ab73517b42adb6cdac1615561 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@victoriametrics.com>
Date: Wed, 15 May 2024 04:03:05 +0200
Subject: [PATCH] wip

---
 lib/logstorage/parser.go | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/lib/logstorage/parser.go b/lib/logstorage/parser.go
index 9d4e76e09..b5e00033e 100644
--- a/lib/logstorage/parser.go
+++ b/lib/logstorage/parser.go
@@ -217,9 +217,32 @@ func (q *Query) AddPipeLimit(n uint64) {
 
 // Optimize tries optimizing the query.
 func (q *Query) Optimize() {
+	q.pipes = optimizeSortOffsetPipes(q.pipes)
 	q.pipes = optimizeSortLimitPipes(q.pipes)
 }
 
+func optimizeSortOffsetPipes(pipes []pipe) []pipe {
+	// Merge 'sort ... | offset ...' into 'sort ... offset ...'
+	i := 1
+	for i < len(pipes) {
+		po, ok := pipes[i].(*pipeOffset)
+		if !ok {
+			i++
+			continue
+		}
+		ps, ok := pipes[i-1].(*pipeSort)
+		if !ok {
+			i++
+			continue
+		}
+		if ps.offset == 0 && ps.limit == 0 {
+			ps.offset = po.n
+		}
+		pipes = append(pipes[:i], pipes[i+1:]...)
+	}
+	return pipes
+}
+
 func optimizeSortLimitPipes(pipes []pipe) []pipe {
 	// Merge 'sort ... | limit ...' into 'sort ... limit ...'
 	i := 1