Dead space in sessionid.tdb

Shilpa K shilpa.krishnareddy at
Fri Aug 22 06:52:21 MDT 2014


We have a problem with sessionid.tdb where it has grown to a large size:

# ls -l sessionid.tdb
-rwxrwxrwx  1 root  wheel  1618509824 Aug 12 14:48 sessionid.tdb

But it does not occupy much disk space.

tdbtool "info" command shows that there is one dead record of huge size:

tdb> info
Size of file/data: 1618509824/160681
Number of records: 101
Smallest/average/largest keys: 14/14/15
Smallest/average/largest data: 1576/1576/1576
Smallest/average/largest padding: 401/401/402
Number of dead records: 1
Smallest/average/largest dead records: 1618305000/1618305000/1618305000
Number of free records: 1
Smallest/average/largest free records: 464/464/464
Number of hash chains: 131
Smallest/average/largest hash chains: 5/13/22
Number of uncoalesced records: 0
Smallest/average/largest uncoalesced runs: 0/0/0
Percentage keys/data/padding/free/dead/rechdrs&tailers/hashes:

tdbtool "check" command shows that most of the space occupied by the TDB is
dead space:

tdb> check
Dead space at 204800-1618509824 (of 1618509824)
Hashes do not match records
Integrity check for the opened database failed.

In the freelist, one of the record is of big size too:

tdb> free
freelist top=[0x604e2420]
entry offset=[0x604e2420], rec.rec_len = [0x00000fa8 (4008)] (end =
entry offset=[0x6046e1a0], rec.rec_len = [0x000007c8 (1992)] (end =
entry offset=[0x604e0c80], rec.rec_len = [0x00000fa8 (4008)] (end =
entry offset=[0x6046ca00], rec.rec_len = [0x00000fa8 (4008)] (end =
entry offset=[0x4d2d3000], rec.rec_len = [0x131999e8 (320444904)] (end =
entry offset=[0x000002b8], rec.rec_len = [0x000001d0 (464)] (end =
total rec_len = [0x1319d278 (320459384)]

Could you please let me know what are the possible circumstances which can
lead to dead space in a TDB?

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