From c207a2d50e094c2a0e54438447ff7fd429af2262 Mon Sep 17 00:00:00 2001
From: Andrew Kane <andrew@ankane.org>
Date: Mon, 11 Mar 2024 19:50:48 -0700
Subject: [PATCH] Reduced lock contention with parallel HNSW index builds

---
 CHANGELOG.md    | 4 ++++
 src/hnswbuild.c | 4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 34af92e..bf81eb0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.6.2 (unreleased)
+
+- Reduced lock contention with parallel HNSW index builds
+
 ## 0.6.1 (2024-03-04)
 
 - Fixed error with `ANALYZE` and vectors with different dimensions
diff --git a/src/hnswbuild.c b/src/hnswbuild.c
index 990fb7f..b5a72ab 100644
--- a/src/hnswbuild.c
+++ b/src/hnswbuild.c
@@ -437,8 +437,8 @@ InsertTupleInMemory(HnswBuildState * buildstate, HnswElement element)
 	char	   *base = buildstate->hnswarea;
 
 	/* Wait if another process needs exclusive lock */
-	LWLockAcquire(entryWaitLock, LW_EXCLUSIVE);
-	LWLockRelease(entryWaitLock);
+	if (LWLockAcquireOrWait(entryWaitLock, LW_EXCLUSIVE))
+		LWLockRelease(entryWaitLock);
 
 	/* Get entry point */
 	LWLockAcquire(entryLock, LW_SHARED);