What should I do if the Virtuoso Server is not responding to HTTP requests?

What?

Manage Virtuoso Server when it is not responding to HTTP requests.

Why?

Observe what activity might be the cause and to remove pending transactions which then will result in enabling the server to start responding to HTTP requests again.

How?

Assume the Virtuoso server is not responding to HTTP requests although SQL connection is working. In order to determine what activity is being performed that might account for this:

  1. Check the status: 

    SQL> status('');
REPORT
VARCHAR
_______________________________________________________________________________


OpenLink Virtuoso VDB Server
Version 06.02.3129-pthreads for Linux as of Mar 16 2011 
Registered to Uriburner (Personal Edition, unlimited connections)
Started on: 2011/03/17 10:49 GMT+60
 
Database Status:
  File size 0, 37598208 pages, 7313125 free.
  1000000 buffers, 993399 used, 76771 dirty 0 wired down, repl age 25548714 0 w. io 0 w/crsr.
  Disk Usage: 2642884 reads avg 4 msec, 30% r 0% w last  1389 s, 1557572 writes,
    15331 read ahead, batch = 79.  Autocompact 308508 in 219226 out, 28% saved.
Gate:  71130 2nd in reads, 0 gate write waits, 0 in while read 0 busy scrap. 
Log = virtuoso.trx, 14922248 bytes
VDB: 0 exec 0 fetch 0 transact 0 error
1757362 pages have been changed since last backup (in checkpoint state)
Current backup timestamp: 0x0000-0x00-0x00
Last backup date: unknown
Clients: 5 connects, max 2 concurrent
RPC: 116 calls, -1 pending, 1 max until now, 0 queued, 2 burst reads (1%), 0 second brk=9521074176
Checkpoint Remap 331113 pages, 0 mapped back. 1180 s atomic time.
    DB master 37598208 total 7313125 free 331113 remap 40593 mapped back
   temp  569856 total 569851 free
 
Lock Status: 52 deadlocks of which 0 2r1w, 86078 waits,
   Currently 1 threads running 0 threads waiting 0 threads in vdb.
Pending:


25 Rows. -- 1274 msec.
SQL>

  2. Connect with the PL debugger and see what is running currently using the info threads call: 

    $ isql 1111 dba <password> -D
DEBUG> info threads

  3. This should return the current code being executed by the Sever.
  4. Run txn_killall() to kill any pending transactions which may enable the server to start responding to HTTP requests again: 

    SQL> txn_killall();

Done. -- 866 msec.

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