SQL*Net & Other Waits
#.2
Network
Locks
Redo
Lib
Cache
Buffer
Cache
Network
IO
Copyright 2006 Kyle Hailey
SQL*Net
6 SQL*Net more data from client
Usually OK, reduce data transferred, possible Network problems
10 SQL*Net more data to client
Usually OK, reduce amount of data transferred, possible Network
tuning needed
14 SQL*Net break/reset to client
Check for errors in sql statement
21 SQL*Net more data from dblink
Reduce data transfer, check net response
31 SQL*Net break/reset to dblink
Check for errors in sql statement sent
Copyright 2006 Kyle Hailey
#.3
SQL*Net Waits
Host Machine
SQL*Plus
OCI
SQL*Forms
SGA
Log
Library Buffer
Buffer Cache
Cache
Buffer
Cache
Log Buffer
etc
Session
Shadow
Copyright 2006 Kyle Hailey
#.4
#.5
SQL*Net Waits P1 and P2
1.
2.
3.
4.
SQL*Net message to client
SQL*Net more data from client
SQL*Net more data to client
SQL*Net more data from dblink

Message and More data


P1 = driver id
P2 = #bytes
5. SQL*Net break/reset to client
6. SQL*Net break/reset to dblink

Break/resets


P1= driver id
P2 = break
Copyright 2006 Kyle Hailey
#.6
SQL*Net message to client
 Time it takes to pack a message to be sent to
the client
 Doesn’t include network timing
http://blog.tanelpoder.com/2008/02/10/sqlnet-message-to-client-vs-sqlnet-more-data-to-client
Waiting
Session
Shadow
Copyright 2006 Kyle Hailey
#.7
SQL*Net more data to client
 Client sends information that spans SDU
packets
 Time it takes to pack
 Doesn’t include network timing
Waiting
Session
Shadow
Copyright 2006 Kyle Hailey
SQL*Net more data from client
 Shadow is sending data to client that spans
packets
 Shadow waits for next packet
 Could indicate


network latency?
Problem with the client tool
Waiting
Session
Shadow
Copyright 2006 Kyle Hailey
#.8
SQL*Net more data from client
#.9
“OEM-lite”
Written in TCL/TK
Only
Overview
SQL
Text
Application Server Crashed
Copyright 2006
#.10
SQL*Net more data from
dblink
 Shadow at db link is sending data to client
that spans packets
 Sends first packet then waits for shadow to
respond, so it can send more
Waiting
Session
dblink
Shadow
Shadow
Copyright 2006 Kyle Hailey
#.11
SDU: More Data
 SDU : Session Data Unit
 Set in sqlnet.ora
trace_level_client=16
trace_directory_client=/tmp
trace_file_client=client.trc
trace_unique_client = true
trace_level_server=16
trace_directory_server=/tmp
trace_file_server=server.trc
TDU – Transmission Data
Unit – see note 44694.1
The TDU parameter has
been deprecated in the
Oracle Net v8.0 and
beyond and is ignored. It
is only mentioned here for
backward compatibility.
client_187.trc:[12-JAN-2008 11:01:38:209] nsconneg: vsn=313,
gbl=0xa01, sdu=2048, tdu=32767
Copyright 2006 Kyle Hailey
#.12
SDU 32K
tnsnames.ora
V10G = (DESCRIPTION =
(SDU=32640)
(ADDRESS = (PROTOCOL = TCP)(HOST = fuji)(PORT = 1522))
(CONNECT_DATA =
(SERVER = DEDICATED) (SERVICE_NAME = v10g)
))
listener.ora
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SDU=32640)
(SID_NAME = v10g)
(ORACLE_HOME = /export/home/oracle10)
))
client_3582.trc:[12-JAN-2008 11:37:39:237] nsconneg: vsn=313,
gbl=0xa01, sdu=32640, tdu=32767
Copyright 2006 Kyle Hailey
#.13
SQL*Net break/reset to client
 Error in sql statement
 Control C
 Usually highlights and error in application
Waiting
Error
Session
Shadow
Copyright 2006 Kyle Hailey
Example
#.14
CREATE TABLE T1 (C1 NUMBER);
ALTER TABLE T1 ADD
(CONSTRAINT T1_CHECK1 CHECK (C1 IN ('J','N')));
ALTER SESSION SET EVENTS
'10046 TRACE NAME CONTEXT FOREVER, LEVEL 12';
INSERT INTO T1 VALUES (1);
PARSING IN CURSOR #2 len=25 dep=0 uid=0 oct=2 lid=0 tim=5009300581224 hv=9816834
09 ad='8e6a7c10'
INSERT INTO T1 VALUES (1)
END OF STMT
PARSE #2:c=0,e=2770,p=0,cr=2,cu=0,mis=1,r=0,dep=0,og=1,tim=5009300581220
BINDS #2:
EXEC #2:c=0,e=128,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,tim=5009300581418
ERROR #2:err=1722 tim=512952379
WAIT #2: nam='SQL*Net break/reset to client' ela= 31 driver id=1650815232 break?
=1 p3=0 obj#=-1 tim=5009300581549
WAIT #2: nam='SQL*Net break/reset to client' ela= 92 driver id=1650815232 break?
=0 p3=0 obj#=-1 tim=5009300581662
Copyright 2006 Kyle Hailey
#.15
SQL*Net break/reset to dblink
 Error in sql statement
 Control C
 Usually highlights and error in application
Waiting
error
Session
dblink
Shadow
Shadow
Copyright 2006 Kyle Hailey
#.16
SQL*Net Waits P1 and P2
 Network/Client/Tool issues


More data from client
More data from dblink
 Try SDU



SQL*Net more data from client
SQL*Net more data to client
SQL*Net more data from dblink
 Application Error


SQL*Net break/reset to client
SQL*Net break/reset to dblink
Copyright 2006 Kyle Hailey