Re: AW: Release transaction???

José Rómulo Elías Contreras Tue, 15 Feb 2005 07:42:45 -0800

Hi,

I have the same problems that Bodo, during havy load of our tomcat application. When no havy load it works well.

Another question, I test the performance of SAPDB in two tomcat servers connecting to the same database. Each tomcat server open 10 sessions with the next parameters:

DriverManager.getConnection(databaseUrl + databaseName + "?user=" + databaseUser + "&password=" + databasePassword + "&timeout=0&isolation=" + java.sql.Connection.TRANSACTION_READ_UNCOMMITTED);

I open 4 differents browser sessions connected 2 to each tomcat server. If I request the same information in each different browser session at the same time the performance go down. The first session connected to tomcatServer1 takes 9 seconds to execute the query, the second session connected to tomcatServer1 takes 12 seconds to execute the query, the third session connected to tomcatServer2 takes 14 seconds to execute the query and the fourth session connected to tomcatServer2 takes 16 seconds to execute the query aproximately. If I open only one browser session to execute the query, then the query takes only 3 seconds.

      Why does the performance go down?
      Why can I correct it?

THANKS

Schroeder, Alexander wrote:

Hello Bodo,
1. If a client crashes, the serve detects the broken connection and performs a 
rollback. This happens almost immediately
  for clients connecting using TCP/IP.
2. Transactions will have locks on some rows, and long running transactions will surely collect more locks than short running transactions, increasing the possibility that these transactions collide and have to wait. Unfortunately, there's never a general way to solve issues related to locking, you need them to analyze on a case-by-case basis.
Regards
Alexander Schr�der
SAP DB, SAP Labs Berlin
________________________________
From: Bodo.Teichmann [mailto:[EMAIL PROTECTED] Sent: Monday, February 14, 2005 9:03 PM To: [email protected] Subject: Re: AW: Release transaction???
Hi, ...but what if the client crashes in the middle of a transaction? how long will sapdb keep the transaktion locks before it release it? and another question (motivated to some strange sapdb behavior, that we saw recently during havy load test of our tomcat application): are there any problems known in sapdb concering transaktion locks? especially if multiple clients start transaktions but need a long time to commit them. seems that sapdb has problems handling such situations , when there are many still uncommitted transaktions. but we did not yet fully analize the problem. does anyone have observed (and hopefully solved) similar problems ? Bodo Teichmann Zabach, Elke schrieb:

Jos� R�mulo El�as Contreras wrote:

Hi: I have an application running over tomcat and with SAPDB 7.4.3.30, but I have I problem: Some times SAPDB hold a transaction and does not release it. In the knldiagerr appears: -------------------------------------------------------------------------- ------ Date Time TID(hex) Typ MsgID Label Message-Text -------------------------------------------------------------------------- ------ 2004-11-22 08:51:18 --- Starting GMT 2004-11-22 08:51:18 7.4.3 Build 030-123-056-274 2004-12-04 10:31:12 0x768 ERR 18431 MESSAGES Could not write to event log, rc = 31 2004-12-04 10:34:44 --- Starting GMT 2004-12-04 10:34:44 7.4.3 Build 030-123-056-274 2004-12-04 14:23:59 0x744 ERR 18431 MESSAGES Could not write to event log, rc = 31 2004-12-04 20:26:11 --- Starting GMT 2004-12-04 20:26:11 7.4.3 Build 030-123-056-274 2004-12-09 15:02:57 --- Starting GMT 2004-12-09 15:02:57 7.4.3 Build 030-123-056-274 2004-12-20 08:30:29 --- Starting GMT 2004-12-20 08:30:29 7.4.3 Build 030-123-056-274 2004-12-23 08:54:48 --- Starting GMT 2004-12-23 08:54:48 7.4.3 Build 030-123-056-274 2005-01-08 18:45:31 --- Starting GMT 2005-01-08 18:45:31 7.4.3 Build 030-123-056-274 2005-01-10 19:17:34 0xA0C ERR 18431 MESSAGES Could not write to event log, rc = 31 2005-01-11 08:23:51 --- Starting GMT 2005-01-11 08:23:51 7.4.3 Build 030-123-056-274 2005-01-14 13:11:54 --- Starting GMT 2005-01-14 13:11:54 7.4.3 Build 030-123-056-274 What does "Starting GMT 2004-11-22 08:51:18" means, and why this appear in the knldiagerr?

knldiagerr will not help in any case to answer you transaction question. If YOU/the application does not send COMMIT/ROLLBACK to the database system, then the current transaction remains open, the locks remain. And during the current transaction there were several INSERT/UPDATE/DELETE made for table DBA.ACCOUNTS_RECEIVABLE. And that transaction was neither commited nor rollbacked at the point of time you selected lockstatistics. Everything seems to work correctly, exactly one transaction is open. Why doe you think that this wrong? Knldiag.err is the error-log of database system for strong errors. Knldiag is the file whose writing starts anew with each start of the database system. Knldiag.err is written more seldom, but for a longer time period. And Starting means, that the database system was started at that (GMT) time and the given version of the database kernel was used for this start. Elke SAP Labs Berlin

What does " 0xA0C ERR 18431 MESSAGES Could not write to event log, rc = 31" means? I can see that in the last transaction that was holding and was not realease, appears the next information in the lock statistics table: *SESSION* *TRANSCOUNT* *SUB_TRANS* *WRITE_TRANS* *PROCESS* *USERNAME* *DATE* *TIME* *TERMID* *REQ_TIMEOUT* *LAST_WRITE* *LOCK_MODE* *LOCK_STATE* *REQ_MODE* *REQ_STATE* *APPL_PROCESS* *APPL_NODEID* *OWNER* *TABLENAME* *TAB LEID* *ROWID_LENGTH* *ROWID_HEX* *ROWID* 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA ACCOUNTS_RECEIVABLE 00000000000002A6 7 00C91391574750000000000000000000 0 139157475 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA DETALLE_ASIGNACION_VEHICULOAO 00000000000002D5 7 00C91391571670000000000000000000 0 139157167 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA DETALLE_ASIGNACION_VEHICULOAO 00000000000002D5 7 00C91391571690000000000000000000 0 139157169 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA DETALLE_ASIGNACION_VEHICULOAO 00000000000002D5 7 00C91391571710000000000000000000 0 139157171 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA DETALLE_ASIGNACION_VEHICULOAO 00000000000002D5 7 00C91391571730000000000000000000 0 139157173 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA FACTURACION_AO 00000000000002DE 7 00C91391574630000000000000000000 0 139157463 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA INVENTORY_MOVEMENT_DOCUMENTS 2.00E+008 7 00C91391574730000000000000000000 0 139157473 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA PEDIDOS_AO 00000000000002F7 7 00C91394124160000000000000000000 0 139412416 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA PEDIDO_DETALLE 00000000000002F8 7 00C91390608010000000000000000000 0 139060801 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_KEYSGENSAP 357 3 00C21200000000000000000000000000 0 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_KEYSGENSAP 357 3 00C22200000000000000000000000000 0 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_KEYSGENSAP 357 7 00C91045100430000000000000000000 0 104510043 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_PATH_HISTORYSAP 000000000000035A 7 00C91391574650000000000000000000 0 139157465 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_PATH_HISTORYSAP 000000000000035A 7 00C91391574670000000000000000000 0 139157467 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_PATH_HISTORYSAP 000000000000035A 7 00C91391574690000000000000000000 0 139157469 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_PATH_HISTORYSAP 000000000000035A 7 00C91391574710000000000000000000 0 139157471 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_PATH_HISTORYSAP 000000000000035A 7 00C91391574720000000000000000000 0 139157472 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_PATH_HISTORYSAP 000000000000035A 7 00C91391574740000000000000000000 0 139157474 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_PATH_HISTORYSAP 000000000000035A 7 00C91391574760000000000000000000 0 139157476 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA WF_PATH_HISTORYSAP 000000000000035A 7 00C91391574780000000000000000000 0 139157478 100046 185074 0 00000006F8FF 37 DBA 2005-01-31 13:30:03 java ? 0 row_exclusive write ? ? 0 app_server DBA CONTACTS 481 6 00C91120802400000000000000000000 0 Why does SAPDB sometimes not release the transaction? THANKS -- MaxDB Discussion Mailing List For list archives: http://lists.mysql.com/maxdb To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]


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