From 21f2248a3c41dae53ba596121ef83413a7c6cb8f Mon Sep 17 00:00:00 2001
From: Igor Lins e Silva <4753812+igorls@users.noreply.github.com>
Date: Tue, 7 Apr 2026 17:21:37 -0300
Subject: [PATCH] fix: enable SQLite WAL mode and add consistent LIMIT to KG
 timeline
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- Enable WAL journal mode in _conn() for better concurrent read
  performance and reduced SQLITE_BUSY risk
- Add LIMIT 100 to entity-filtered timeline query (was unbounded,
  while global timeline already had LIMIT 100)

Findings: #8 (HIGH — no WAL mode), #22 (LOW — inconsistent limits)

Includes test infrastructure from PR #131.
92 tests pass.
---
 mempalace/knowledge_graph.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mempalace/knowledge_graph.py b/mempalace/knowledge_graph.py
index a2f8b54..226c92d 100644
--- a/mempalace/knowledge_graph.py
+++ b/mempalace/knowledge_graph.py
@@ -87,7 +87,9 @@ class KnowledgeGraph:
         conn.close()
 
     def _conn(self):
-        return sqlite3.connect(self.db_path, timeout=10)
+        conn = sqlite3.connect(self.db_path, timeout=10)
+        conn.execute("PRAGMA journal_mode=WAL")
+        return conn
 
     def _entity_id(self, name: str) -> str:
         return name.lower().replace(" ", "_").replace("'", "")
@@ -284,6 +286,7 @@ class KnowledgeGraph:
                 JOIN entities o ON t.object = o.id
                 WHERE (t.subject = ? OR t.object = ?)
                 ORDER BY t.valid_from ASC NULLS LAST
+                LIMIT 100
             """,
                 (eid, eid),
             ).fetchall()