diff options
Diffstat (limited to 'src/libstore/db.cc')
| -rw-r--r-- | src/libstore/db.cc | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/src/libstore/db.cc b/src/libstore/db.cc index 5c8e7edec..f01cefd79 100644 --- a/src/libstore/db.cc +++ b/src/libstore/db.cc @@ -165,11 +165,30 @@ void Database::open(const string & path) DbEnv * env = 0; /* !!! close on error */ env = new DbEnv(0); + /* Smaller log files. */ env->set_lg_bsize(32 * 1024); /* default */ env->set_lg_max(256 * 1024); /* must be > 4 * lg_bsize */ - env->set_lk_detect(DB_LOCK_DEFAULT); + + /* Write the log, but don't sync. This protects transactions + against application crashes, but if the system crashes, + some transactions may be undone. An acceptable risk, I + think. */ env->set_flags(DB_TXN_WRITE_NOSYNC | DB_LOG_AUTOREMOVE, 1); - + + /* Increase the locking limits. If you ever get `Dbc::get: + Cannot allocate memory' or similar, especially while + running `nix-store --verify', just increase the following + number, then run db_recover on the database to remove the + existing DB environment (since changes only take effect on + new environments). */ + env->set_lk_max_locks(4000); + env->set_lk_max_lockers(4000); + env->set_lk_max_objects(4000); + env->set_lk_detect(DB_LOCK_DEFAULT); + + /* Dangerous, probably, but from the docs it *seems* that BDB + shouldn't sync when DB_TXN_WRITE_NOSYNC is used, but it + still fsync()s sometimes. */ db_env_set_func_fsync(my_fsync); |