From 1647ab5ed48ed627857fda5955a37dcbee02b706 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=85=B0=E5=B7=9E=E5=B0=8F=E7=BA=A2=E9=B8=A1?=
 <flyphp@outlook.com>
Date: Mon, 6 Nov 2023 17:48:32 +0800
Subject: [PATCH] Reduce the blocking time of the write lock when deleting
 space

When the number of parts of a space is relatively large and the amount of data written is also large, it will block for a long time in the removeSpace function when deleting the space. Affect business read and write
---
 src/kvstore/NebulaStore.cpp | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/kvstore/NebulaStore.cpp b/src/kvstore/NebulaStore.cpp
index 218062413e3..91621a1be68 100644
--- a/src/kvstore/NebulaStore.cpp
+++ b/src/kvstore/NebulaStore.cpp
@@ -516,13 +516,17 @@ std::shared_ptr<Part> NebulaStore::newPart(GraphSpaceID spaceId,
 }
 
 void NebulaStore::removeSpace(GraphSpaceID spaceId) {
-  folly::RWSpinLock::WriteHolder wh(&lock_);
-  if (beforeRemoveSpace_) {
-    beforeRemoveSpace_(spaceId);
+  {
+    folly::RWSpinLock::WriteHolder wh(&lock_);
+    if (beforeRemoveSpace_) {
+      beforeRemoveSpace_(spaceId);
+    }
   }
 
-  auto spaceIt = this->spaces_.find(spaceId);
-  if (spaceIt != this->spaces_.end()) {
+  auto spaceOr = space(spaceId);
+  if (ok(spaceOr)) {
+    folly::RWSpinLock::WriteHolder wh(&lock_);
+    auto spaceIt = this->spaces_.find(spaceId);
     for (auto& [partId, part] : spaceIt->second->parts_) {
       // before calling removeSpace, meta client would call removePart to remove all parts in
       // meta cache, which do not contain learners, so we remove them here
@@ -530,6 +534,10 @@ void NebulaStore::removeSpace(GraphSpaceID spaceId) {
         removePart(spaceId, partId, false);
       }
     }
+    this->spaces_.erase(spaceIt);
+  }
+  if (ok(spaceOr)) {
+    auto spaceIt = value(spaceOr);
     auto& engines = spaceIt->second->engines_;
     for (auto& engine : engines) {
       auto parts = engine->allParts();
@@ -538,14 +546,13 @@ void NebulaStore::removeSpace(GraphSpaceID spaceId) {
       }
       CHECK_EQ(0, engine->totalPartsNum());
     }
-    CHECK(spaceIt->second->parts_.empty());
+    CHECK(spaceIt->parts_.empty());
     std::vector<std::string> enginePaths;
     if (FLAGS_auto_remove_invalid_space) {
       for (auto& engine : engines) {
         enginePaths.emplace_back(engine->getDataRoot());
       }
     }
-    this->spaces_.erase(spaceIt);
     if (FLAGS_auto_remove_invalid_space) {
       for (const auto& path : enginePaths) {
         removeSpaceDir(path);