From 65206b0446d243470219afa171a8a5dae6e8c8e6 Mon Sep 17 00:00:00 2001
From: yiguolei <guolei@selectdb.com>
Date: Wed, 31 Dec 2025 09:29:56 +0800
Subject: [PATCH] [memorygc](lrucache) do not prune memory if prune is disabled
 (#59478)

### What problem does this PR solve?

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:

### Release note

None

### Check List (For Author)

- Test <!-- At least one of them must be included. -->
    - [ ] Regression test
    - [ ] Unit Test
    - [ ] Manual test (add detailed scripts or steps below)
    - [ ] No need to test or manual test. Explain why:
- [ ] This is a refactor/code format and no logic has been changed.
        - [ ] Previous test can cover this change.
        - [ ] No code files have been changed.
        - [ ] Other reason <!-- Add your reason?  -->

- Behavior changed:
    - [ ] No.
    - [ ] Yes. <!-- Explain the behavior change -->

- Does this need documentation?
    - [ ] No.
- [ ] Yes. <!-- Add document PR link here. eg:
https://github.com/apache/doris-website/pull/1214 -->

### Check List (For Reviewer who merge this PR)

- [ ] Confirm the release note
- [ ] Confirm test cases
- [ ] Confirm document
- [ ] Add branch pick label <!-- Add branch pick label that this PR
should merge into -->
---
 be/src/runtime/memory/lru_cache_policy.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/be/src/runtime/memory/lru_cache_policy.h b/be/src/runtime/memory/lru_cache_policy.h
index c06a6a03982011..a33fa0cb262416 100644
--- a/be/src/runtime/memory/lru_cache_policy.h
+++ b/be/src/runtime/memory/lru_cache_policy.h
@@ -254,7 +254,11 @@ class LRUCachePolicy : public CachePolicy {
         if (_cache == ExecEnv::GetInstance()->get_dummy_lru_cache()) {
             return 0;
         }
-
+        if (!_enable_prune) {
+            LOG(INFO) << "[MemoryGC] " << type_string(_type)
+                      << " cache prune disabled, so could not adjust capacity to free memory";
+            return 0;
+        }
         size_t old_capacity = get_capacity();
         int64_t old_mem_consumption = mem_consumption();
         int64_t old_usage = get_usage();