Andre Reitz  wrote:

> Hy all, we have a "hang" in our web-based databaseapplication.
> 
> Something blocks our clients.
> 
> Please see the queryresult below or in the attachment.
> 
> Please tell me if my interpretation of the output is correct:
> 
> - There are Two sessions (different connections: 1809398 and 1809399)
> - Session 1809398 waits for a "row_exclusive"
>   lock on table "IQ_ZUO_FB_SA" for row "0x00c6193799000000c52633"
> - Session 1809399 waits for a "tab_share"
>   lock on table "IQ_ZUO_FB_AV" for the complete table
> - both sessions can never succeed because:
>   * Session 1809398 has already a "row_exclusive" lock on "IQ_ZUO_FB_AV"
>   * Session 1809399 has already a "tab_share"     lock on "IQ_ZUO_FB_SA"
> - This situation is a "Deadlock"
> 
> If my interpretation is correct:
> - What kind of queries could be responsible for the "tab_share" locks
>   in Session 1809399?
> - Why is this deadlock not encountered by the automatic deadlockdetection?
> 
> 
Which isolation level do you use?
Tab_Share locks may be caused by isolation level 15 / 2/20 / 3/30 and not by lock 
escalations.

Did you check your transaction-structure, meaning: do you hold locks too long because 
uncommitted transactions / not committed as often as would be convenient?

I assume that you do not lock the tables explicitly?

Elke
SAP Labs Berlin

> 
> Greetings, and thank you very much in advance.
> 
> Andre'
> 
> P.S.: We use sapdb 7.4.3.27-1 on Linux (rpm distribution)
>       The clients connect with python.
> 
> 
> 
> 
> 
> SELECT * FROM LOCKSTATISTICS;
> 
> 
> 
> 
> SESSION |           TRANSCOUNT | SUB_TRANS |    WRITE_TRANS | PROCESS |
> USERNAME |     DATE |     TIME | TERMID | REQTIMEOUT |  LASTWRITE |
> LOCKMODE | LOCKSTATE |       REQMODE | REQSTATE | APPLPROCESS |
> APPLNODE |           OWNER |     TABLENAME |            TABLEID |
> ROWIDLENGTH |                 ROWIDHEX |       ROWID
> --------+----------------------+-----------+----------------+---------+---
> --------------+----------+----------+--------+------------+------------+--
> -------------+-----------+---------------+----------+-------------+-------
> ------+-----------------+---------------+--------------------+------------
> -+--------------------------+------------
> 1809398 |                46194 |         0 | 0x0000001df4e6 |      53 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |        150 |
> row_exclusive |     write |          NULL |     NULL |       28082 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX | IQ_FRAGEBOGEN | 0x0000000000003c98 |
> 5 |             0x00c6193799 |
> 1809398 |                46194 |         0 | 0x0000001df4e6 |      53 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |        150 |
> NULL |      NULL | row_exclusive |    write |       28082 | xxxxxxxxxxx |
> XXXXXXXXXXXXXXX |  IQ_ZUO_FB_SA | 0x0000000000003cb7 |          11 |
> 0x00c6193799000000c52633 |      193799
> 1809398 |                46194 |         0 | 0x0000001df4e6 |      53 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |        150 |
> row_exclusive |     write |          NULL |     NULL |       28082 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX |  IQ_ZUO_FB_AV | 0x0000000000003eb4 |
> 5 |             0x00c6193799 |
> 1809398 |                46194 |         0 | 0x0000001df4e6 |      53 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |        150 |
> row_exclusive |     write |          NULL |     NULL |       28082 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX |  IQ_ZUO_FB_AK | 0x0000000000003eb5 |
> 5 |             0x00c6193799 |
> 1809398 |                46194 |         0 | 0x0000001df4e6 |      53 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |        150 |
> row_exclusive |     write |          NULL |     NULL |       28082 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX |  IQ_ZUO_FB_PB | 0x0000000000003eb6 |
> 5 |             0x00c6193799 |
> 1809399 |                46195 |         0 |           NULL |      54 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |       NULL |
> tab_share |      temp |          NULL |     NULL |       28079 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX |  IQ_ZUO_FB_SA | 0x0000000000003cb7 |
> 0 |                     NULL |        NULL
> 1809399 |                46195 |         0 |           NULL |      54 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |       NULL |
> tab_share |      temp |          NULL |     NULL |       28079 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX |  IQ_ZUO_FB_WF | 0x0000000000003cb8 |
> 0 |                     NULL |        NULL
> 1809399 |                46195 |         0 |           NULL |      54 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |       NULL |
> tab_share |      temp |          NULL |     NULL |       28079 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX |  IQ_ZUO_FB_TF | 0x0000000000003cb9 |
> 0 |                     NULL |        NULL
> 1809399 |                46195 |         0 |           NULL |      54 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |       NULL |
> tab_share |      temp |          NULL |     NULL |       28079 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX |  IQ_ZUO_FB_MA | 0x0000000000003cba |
> 0 |                     NULL |        NULL
> 1809399 |                46195 |         0 |           NULL |      54 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |       NULL |
> tab_share |      temp |          NULL |     NULL |       28079 |
> xxxxxxxxxxx | XXXXXXXXXXXXXXX |  IQ_ZUO_FB_EA | 0x0000000000003cbb |
> 0 |                     NULL |        NULL
> 1809399 |                46195 |         0 |           NULL |      54 |
> XXXXXXXXXXXXXXX | 20040527 | 00153933 |   web2 |       4850 |       NULL |
> NULL |      NULL |     tab_share |     temp |       28079 | xxxxxxxxxxx |
> XXXXXXXXXXXXXXX |  IQ_ZUO_FB_AV | 0x0000000000003eb4 |           0 |
> NULL |        NULL
> 
> 
> 
> 
> 
> 
> --
> __________________________________________________________________________
> 
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