From b66594a4e361b7363ccec13680d158f90a71e04b Mon Sep 17 00:00:00 2001
From: Jonathan McDowell <noodles@earth.li>
Date: Mon, 28 Mar 2011 18:35:25 -0700
Subject: [PATCH] Configure db4 locks according to maxkeys and actually check
maxkeys
The number of db4 objects iin use is related to the maximum number of
keys we return at once. Configure the locking subsystem accordingly
and limit the number of returned keys to maxkeys.
Significantly improves the reliability of the db4 backend on a large
busy server.
---
keydb_db4.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/keydb_db4.c b/keydb_db4.c
index 8990758..6fbf9da 100644
--- a/keydb_db4.c
+++ b/keydb_db4.c
@@ -277,6 +277,7 @@ static void db4_initdb(bool readonly)
int i = 0;
u_int32_t flags = 0;
struct stat statbuf;
+ int maxlocks;
snprintf(buf, sizeof(buf) - 1, "%s/%s", config.db_dir,
DB4_UPGRADE_FILE);
@@ -329,6 +330,17 @@ static void db4_initdb(bool readonly)
}
}
+ /*
+ * Up the number of locks we're allowed at once. We base this on
+ * the maximum number of keys we're going to return.
+ */
+ maxlocks = config.maxkeys * 16;
+ if (maxlocks < 1000) {
+ maxlocks = 1000;
+ }
+ dbenv->set_lk_max_locks(dbenv, maxlocks);
+ dbenv->set_lk_max_objects(dbenv, maxlocks);
+
/*
* Enable deadlock detection so that we don't block indefinitely on
* anything. What we really want is simple 2 state locks, but I'm not
@@ -690,6 +702,10 @@ static int db4_fetch_key_text(const char *search,
}
llfree(wordlist, NULL);
wordlist = NULL;
+
+ if (keylist.count > config.maxkeys) {
+ keylist.count = config.maxkeys;
+ }
db4_starttrans();
for (i = 0; i < keylist.count; i++) {
--
2.39.5