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lmdb-safe
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Allow configuring maximum number of DBs

This commit is contained in:
Martchus 2022-01-16 20:05:34 +01:00
parent 97fab01b15
commit 6a2a752203
2 changed files with 7 additions and 7 deletions
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10
lmdb-safe.cc
View File

@ -25,14 +25,14 @@ MDBDbi::MDBDbi(MDB_env* env, MDB_txn* txn, const string_view dbname, unsigned in
// Database names are keys in the unnamed database, and may be read but not written.
}
MDBEnv::MDBEnv(const char* fname, unsigned int flags, mdb_mode_t mode)
MDBEnv::MDBEnv(const char* fname, unsigned int flags, mdb_mode_t mode, MDB_dbi maxDBs)
{
mdb_env_create(&d_env);
if(const auto rc = mdb_env_set_mapsize(d_env, 16ULL * 4096 * 244140ULL)) { // 4GB
throw std::runtime_error("setting map size: " + MDBError(rc));
}
// Various other options may also need to be set before opening the handle, e.g. mdb_env_set_mapsize(), mdb_env_set_maxreaders(), mdb_env_set_maxdbs(),
if (const auto rc = mdb_env_set_maxdbs(d_env, 128)) {
if (const auto rc = mdb_env_set_maxdbs(d_env, maxDBs)) {
throw std::runtime_error("setting maxdbs: " + MDBError(rc));
}
@ -80,7 +80,7 @@ int MDBEnv::getROTX()
}
std::shared_ptr<MDBEnv> getMDBEnv(const char* fname, unsigned int flags, mdb_mode_t mode)
std::shared_ptr<MDBEnv> getMDBEnv(const char* fname, unsigned int flags, mdb_mode_t mode, MDB_dbi maxDBs)
{
struct Value
{
@ -97,7 +97,7 @@ std::shared_ptr<MDBEnv> getMDBEnv(const char* fname, unsigned int flags, mdb_mod
throw std::runtime_error("Unable to stat prospective mdb database: "+string(strerror(errno)));
else {
std::lock_guard<std::mutex> l(mut);
auto fresh = std::make_shared<MDBEnv>(fname, flags, mode);
auto fresh = std::make_shared<MDBEnv>(fname, flags, mode, maxDBs);
if(stat(fname, &statbuf))
throw std::runtime_error("Unable to stat prospective mdb database: "+string(strerror(errno)));
auto key = std::tie(statbuf.st_dev, statbuf.st_ino);
@ -122,7 +122,7 @@ std::shared_ptr<MDBEnv> getMDBEnv(const char* fname, unsigned int flags, mdb_mod
}
}
auto fresh = std::make_shared<MDBEnv>(fname, flags, mode);
auto fresh = std::make_shared<MDBEnv>(fname, flags, mode, maxDBs);
s_envs[key] = {fresh, flags};
return fresh;

4
lmdb-safe.hh
View File

@ -69,7 +69,7 @@ using MDBRWTransaction = std::unique_ptr<MDBRWTransactionImpl>;
class MDBEnv
{
public:
MDBEnv(const char* fname, unsigned int flags, mdb_mode_t mode);
MDBEnv(const char* fname, unsigned int flags, mdb_mode_t mode, MDB_dbi maxDBs);
~MDBEnv()
{
@ -102,7 +102,7 @@ private:
std::map<std::thread::id, int> d_ROtransactionsOut;
};
std::shared_ptr<MDBEnv> getMDBEnv(const char* fname, unsigned int flags, mdb_mode_t mode);
std::shared_ptr<MDBEnv> getMDBEnv(const char* fname, unsigned int flags, mdb_mode_t mode, MDB_dbi maxDBs = 128);