[PATCH v3 7/9] perf python event_analyzing_sample: Default to in-memory SQLite database

[Ian Rogers]

When -d/--db is not specified, event_analyzing_sample.py created a
temporary file in /tmp via tempfile.mkstemp() and deleted it in
trace_end(). As noted during review, creating the database in a shared
/tmp directory does not reserve SQLite's auxiliary sidecar filenames
(-journal or -wal), and a temporary on-disk file is unnecessary when the
caller did not ask to persist the database.

Default to sqlite3.connect(":memory:") when db_path is not provided,
removing the temporary file creation and cleanup logic, and test both
the default in-memory mode and explicit -d file mode in
test_event_analyzing_sample_python.sh.

Fixes: eeb70645a809 ("perf python: Port event_analyzing_sample to perf module")
Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/python/event_analyzing_sample.py   | 35 ++++++-------------
 .../test_event_analyzing_sample_python.sh     |  8 ++++-
 2 files changed, 17 insertions(+), 26 deletions(-)

diff --git a/tools/perf/python/event_analyzing_sample.py b/tools/perf/python/event_analyzing_sample.py
index 15b47cff9fa3..b4efee88d94b 100755
--- a/tools/perf/python/event_analyzing_sample.py
+++ b/tools/perf/python/event_analyzing_sample.py
@@ -17,10 +17,8 @@ from __future__ import annotations
 
 import argparse
 import math
-import os
 import sqlite3
 import struct
-import tempfile
 from typing import Any
 import perf
 
@@ -117,16 +115,11 @@ session: Any = None
 
 class _DB:
     con: sqlite3.Connection | None = None
-    temp_path: str | None = None
 
 def trace_begin(db_path: str | None = None) -> None:
     """Initialize database tables."""
     print("In trace_begin:\n")
-    if not db_path:
-        fd, db_path = tempfile.mkstemp(prefix="perf_events_", suffix=".db")
-        os.close(fd)
-        _DB.temp_path = db_path
-    con = sqlite3.connect(db_path)
+    con = sqlite3.connect(db_path or ":memory:")
     try:
         # Drop any pre-existing tables so repeated runs do not accumulate duplicate events.
         con.execute("drop table if exists gen_events;")
@@ -297,28 +290,20 @@ def show_pebs_ll() -> None:
 def trace_end() -> None:
     """Called at the end of trace processing."""
     print("In trace_end:\n")
-    try:
-        if _DB.con:
-            try:
-                _DB.con.commit()
-                show_general_events()
-                show_pebs_ll()
-            finally:
-                _DB.con.close()
-                _DB.con = None
-    finally:
-        if _DB.temp_path and os.path.exists(_DB.temp_path):
-            try:
-                os.remove(_DB.temp_path)
-            except OSError:
-                pass
-            _DB.temp_path = None
+    if _DB.con:
+        try:
+            _DB.con.commit()
+            show_general_events()
+            show_pebs_ll()
+        finally:
+            _DB.con.close()
+            _DB.con = None
 
 if __name__ == "__main__":
     ap = argparse.ArgumentParser(description="Analyze events with SQLite")
     ap.add_argument("-i", "--input", default="perf.data", help="Input file name")
     ap.add_argument("-d", "--db", "--database", dest="database", default=None,
-                    help="Database file name (defaults to a temporary file cleaned up on exit)")
+                    help="Database file name (defaults to an in-memory database)")
     args = ap.parse_args()
 
     try:
diff --git a/tools/perf/tests/shell/test_event_analyzing_sample_python.sh b/tools/perf/tests/shell/test_event_analyzing_sample_python.sh
index 5f0a41080acf..cddb12b67698 100755
--- a/tools/perf/tests/shell/test_event_analyzing_sample_python.sh
+++ b/tools/perf/tests/shell/test_event_analyzing_sample_python.sh
@@ -45,8 +45,14 @@ test_file_mode() {
 		exit 2
 	fi
 
-	# Run the script
+	# Run the script with default (:memory:) database and with explicit -d path
 	if ! perf script event_analyzing_sample -i "${temp_data}" \
+		> "${temp_dir}/perf.mem.out" 2>&1 || \
+	   ! grep -q "Statistics about the general events" "${temp_dir}/perf.mem.out" || \
+	   grep -q "Error creating/inserting event" "${temp_dir}/perf.mem.out"; then
+		echo "Default in-memory database mode test failed."
+		err=1
+	elif ! perf script event_analyzing_sample -i "${temp_data}" \
 		-d "${temp_db}" > "${temp_dir}/perf.out" 2>&1; then
 		echo "File mode test failed."
 		err=1
-- 
2.56.0.rc1.315.gc6ed9934b7-goog