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-rw-r--r--lib/tdb2/doc/TDB1_porting.txt28
1 files changed, 28 insertions, 0 deletions
diff --git a/lib/tdb2/doc/TDB1_porting.txt b/lib/tdb2/doc/TDB1_porting.txt
index 90ba249738..ef305cabba 100644
--- a/lib/tdb2/doc/TDB1_porting.txt
+++ b/lib/tdb2/doc/TDB1_porting.txt
@@ -42,3 +42,31 @@ Interface differences between TDB1 and TDB2.
tdb_lockall_read(): child must call tdb_unlockall_read()
tdb_chainlock(): child must call tdb_chainunlock()
tdb_parse() callback: child must return from tdb_parse()
+
+- tdb2 will not open a non-tdb file, even if O_CREAT is specified.
+
+- There is no tdb_traverse_read. For operating on TDB1 files, you can
+ simulate it by tdb_add_flag(tdb, TDB_RDONLY); tdb_traverse();
+ tdb_remove_flag(tdb, TDB_RDONLY). This may be desirable because
+ traverse on TDB1 files use a write lock on the entire database
+ unless it's read-only.
+
+- Failure inside a transaction (such as a lock function failing) does
+ not implicitly cancel the transaction; you still need to call
+ tdb_transaction_cancel().
+
+TDB1 Compatibility:
+
+- tdb2's offers a tdb1_incompatible_hash function, which is the same
+ as the default hash with the TDB_INCOMPATIBLE_HASH flag. There is
+ no way of marking an old TDB incompatible with versions < 1.2.6
+ while using any other hash.
+
+- The TDB_ATTRIBUTE_TDB1_HASHSIZE attribute can be used to control the
+ hash size, but only when creating (ie. O_CREAT) a TDB1
+ (ie. TDB_VERSION1).
+
+- There is no TDB_CLEAR_IF_FIRST flag; it has severe scalability and
+ API problems. If necessary, you can emulate this by using the open
+ hook and placing a 1-byte lock at offset 4. If your program forks,
+ you will need to place this lock again in the child.