Hello.
After update Samba from v. 3.0.28a to v. 3.2.15 we've noticed that
winbibdd_cache.tdb
file has been increased up to 10 times. After some testing we got the
following file
sizes (in bytes)
6 users in AD: 3.0.28a - 53248, 3.2.15 - 389120
1005 users in AD: 0.28a - 1802240, 3.2.15 - 13963264
10005 users in AD: 0.28a - 18464768, 3.2.15 - 144846848
We've found out that 3.2.15 uses another algorythm for making room for
new records in the
tdb file. If 3.0.28a allocates space for at least 10 more records,
3.2.15 allocates space
for at least 100 more records, and at least 25% more space.
We've created a patch which transfers algorythm for allocation space from
3.0.28a.
After using this patch we've got the next results:
6 users in AD: 3.0.28a - 53248, 3.2.15 patched - 61440
1005 users in AD: 0.28a - 1802240, 3.2.15 patched - 1922916
10005 users in AD: 0.28a - 18464768, 3.2.15 patched - 19709952
But we have some doubts as for the correctness of the patch and we're
not sure that it
won't damage anything.
Please, clarify this item.
Thanks...
Regards, Vladimir
[samba-3.2.15.winbind_cache.size.research.diff]
*** samba-3.2.15/source/lib/tdb/common/io.c 2009-09-30 15:24:50.000000000 +0300
--- samba-3.2.15.patched/source/lib/tdb/common/io.c 2009-10-23 17:56:24.000000000 +0300
***************
*** 306,316 ****
/* must know about any previous expansions by another process */
tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
! /* always make room for at least 100 more records, and at
! least 25% more space. Round the database up to a multiple
! of the page size */
! new_size = MAX(tdb->map_size + size*100, tdb->map_size * 1.25);
! size = TDB_ALIGN(new_size, tdb->page_size) - tdb->map_size;
if (!(tdb->flags & TDB_INTERNAL))
tdb_munmap(tdb);
--- 306,314 ----
/* must know about any previous expansions by another process */
tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
! /* always make room for at least 10 more records, and round
! the database up to a multiple of the page size */
! size = TDB_ALIGN(tdb->map_size + size*10, tdb->page_size) - tdb->map_size;
if (!(tdb->flags & TDB_INTERNAL))
tdb_munmap(tdb);
