Date:   Fri, 3 Dec 2021 16:55:31 -0500
From:   Bruce Fields <bfields@fieldses.org>
To:     Steve Dickson <steved@redhat.com>
Cc:     dai.ngo@oracle.com, linux-nfs@vger.kernel.org
Subject: [PATCH] nfsdcld: use WAL journal for faster commits
Message-ID: <20211203215531.GC3930@fieldses.org>
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From: "J. Bruce Fields" <bfields@redhat.com>

Currently nfsdcld is doing three fdatasyncs for each upcall.  Based on
SQLite documentation, WAL mode should also be safe, and I can confirm
from an strace that it results in only one fdatasync each.

This may be a bottleneck e.g. when lots of clients are being created or
expired at once (e.g. on reboot).

Not bothering with error checking, as this is just an optimization and
nfsdcld will still function without.  (Might be better to log something
on failure, though.)

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
 utils/nfsdcld/sqlite.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/utils/nfsdcld/sqlite.c b/utils/nfsdcld/sqlite.c
index 03016fb95823..b248eeffa204 100644
--- a/utils/nfsdcld/sqlite.c
+++ b/utils/nfsdcld/sqlite.c
@@ -826,6 +826,9 @@ sqlite_prepare_dbh(const char *topdir)
 		goto out_close;
 	}
 
+	sqlite3_exec(dbh, "PRAGMA journal_mode = WAL;", NULL, NULL, NULL);
+	sqlite3_exec(dbh, "PRAGMA synchronous = FULL;", NULL, NULL, NULL);
+
 	ret = sqlite_query_schema_version();
 	switch (ret) {
 	case CLD_SQLITE_LATEST_SCHEMA_VERSION:
-- 
2.33.1