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Diffstat (limited to 'source4/lib/tdb/docs/README')
| -rw-r--r-- | source4/lib/tdb/docs/README | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/source4/lib/tdb/docs/README b/source4/lib/tdb/docs/README index 664d65ffd9..18b32de37f 100644 --- a/source4/lib/tdb/docs/README +++ b/source4/lib/tdb/docs/README @@ -40,6 +40,7 @@ The interface is very similar to gdbm except for the following: - no tdbm_reorganise() function - no tdbm_sync() function. No operations are cached in the library anyway - added a tdb_traverse() function for traversing the whole database +- added transactions support A general rule for using tdb is that the caller frees any returned TDB_DATA structures. Just call free(p.dptr) to free a TDB_DATA @@ -67,6 +68,19 @@ TDB_CONTEXT *tdb_open(char *name, int hash_size, int tdb_flags, memory. The filename is ignored in this case. TDB_NOLOCK - don't do any locking TDB_NOMMAP - don't use mmap + TDB_NOSYNC - don't synchronise transactions to disk + +---------------------------------------------------------------------- +TDB_CONTEXT *tdb_open_ex(char *name, int hash_size, int tdb_flags, + int open_flags, mode_t mode, + tdb_log_func log_fn, + tdb_hash_func hash_fn) + +This is like tdb_open(), but allows you to pass an initial logging and +hash function. Be careful when passing a hash function - all users of +the database must use the same hash function or you will get data +corruption. + ---------------------------------------------------------------------- char *tdb_error(TDB_CONTEXT *tdb); @@ -164,3 +178,40 @@ int tdb_lockchain(TDB_CONTEXT *tdb, TDB_DATA key); int tdb_unlockchain(TDB_CONTEXT *tdb, TDB_DATA key); unlock one hash chain + +---------------------------------------------------------------------- +int tdb_transaction_start(TDB_CONTEXT *tdb) + + start a transaction. All operations after the transaction start can + either be committed with tdb_transaction_commit() or cancelled with + tdb_transaction_cancel(). + + If you call tdb_transaction_start() again on the same tdb context + while a transaction is in progress, then the same transaction + buffer is re-used. The number of tdb_transaction_{commit,cancel} + operations must match the number of successful + tdb_transaction_start() calls. + + Note that transactions are by default disk synchronous, and use a + recover area in the database to automatically recover the database + on the next open if the system crashes during a transaction. You + can disable the synchronous transaction recovery setup using the + TDB_NOSYNC flag, which will greatly speed up operations at the risk + of corrupting your database if the system crashes. + + Operations made within a transaction are not visible to other users + of the database until a successful commit. + +---------------------------------------------------------------------- +int tdb_transaction_cancel(TDB_CONTEXT *tdb) + + cancel a current transaction, discarding all write and lock + operations that have been made since the transaction started. + + +---------------------------------------------------------------------- +int tdb_transaction_commit(TDB_CONTEXT *tdb) + + commit a current transaction, updating the database and releasing + the transaction locks. + |