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Wait Event Enhancements in Oracle 10g Terry Sutton and Roger Schrag Database Specialists, Inc. www.dbspecialists.com Today’s Session Twelve wait event interface enhancements in Oracle 10g that we really like. Documentation gaps in some areas make this information harder to come by.

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wait event enhancements in oracle 10g
Wait Event Enhancementsin Oracle 10g

Terry Sutton and Roger Schrag

Database Specialists, Inc.

www.dbspecialists.com

today s session
Today’s Session

Twelve wait event interface enhancements in Oracle 10g that we really like.

Documentation gaps in some areas make this information harder to come by.

We will assume everyone is familiar with wait event concepts and the wait event interface in Oracle 9i or earlier.

To learn more about wait events, read: www.dbspecialists.com/presentations.html#wait_events

white paper
White Paper
  • Contains additional detail we won’t have time to cover today.
  • Includes a handy reference list of all Oracle 10g wait events, wait classes, and wait event parameters.
  • Download: www.dbspecialists.com/presentations
twelve oracle 10g enhancements
Twelve Oracle 10g Enhancements
  • More descriptive wait event names
  • Wait event classes
  • v$event_name new columns
  • v$sql / v$sqlarea new columns
  • v$session_wait_history
  • v$session new columns
  • v$event_histogram
  • v$system_wait_class / v$session_wait_class
  • Active Session History (ASH)
  • Automatic Workload Repository (AWR)
  • Time model statistics
  • Improved session tracing
more descriptive names
More Descriptive Names
  • Prior to Oracle 10g many wait events had vague names that covered many situations:
    • latch free
    • enqueue
    • buffer busy waits
  • For these waits you had to look at parameter values to learn the wait condition.
  • Oracle 10g gives the most common of these types of waits more descriptive names.
latch free
latch free
  • Prior to Oracle 10g: Could indicate a wait on any of dozens of different latches.
  • Oracle 10g: The 26 most common latches have their own wait event.
    • The rest continue to use the generic “latch free” wait event.
latch free prior to oracle 10g
latch free Prior to Oracle 10g

SQL> SELECT event, state, p1, p2, p3 FROM v$session_wait WHERE sid = 162;

EVENT STATE P1 P2 P3

------------- ------- ----------- ------ -----

latch free WAITING 15113593728 97 5

SQL> SELECT * FROM v$event_name WHERE name = \'latch free\';

EVENT# NAME PARAMETER1 PARAMETER2 PARAMETER3

------ ---------- --------------- --------------- ---------------

3 latch free address number tries

SQL> SELECT name FROM v$latch WHERE latch# = 97;

NAME

--------------------

cache buffers chains

latch free in oracle 10g
latch free in Oracle 10g

SQL> SELECT event, state

2 FROM v$session_wait

3 WHERE sid = 162;

EVENT STATE

------------------------------ -------

latch: cache buffers chains WAITING

  • The more descriptive wait event name saves us the effort of decoding wait event parameters.
enqueue
enqueue
  • Prior to Oracle 10g: Could indicate a wait on any of a few dozen different types of enqueues.
  • Oracle 10g: 184 distinct wait events replace the one generic “enqueue” wait event:
    • Event names differentiate the enqueue type and sometimes even the contention type.
    • Parameter names are more descriptive than generic “id1” and “id2”.
enqueue prior to oracle 10g
enqueue Prior to Oracle 10g

SQL> SELECT event, state, seconds_in_wait FROM v$session_wait WHERE sid = 96;

EVENT STATE SECONDS_IN_WAIT

----------------------------------- ------------------- ---------------

enqueue WAITING 24

SQL> SELECT sid, CHR (BITAND (p1,-16777216) / 16777215) ||

2 CHR (BITAND (p1, 16711680) / 65535) enq,

3 DECODE (CHR (BITAND (p1,-16777216) / 16777215) ||

4 CHR (BITAND (p1, 16711680) / 65535),

5 \'TX\', \'Transaction (RBS)\',

...

13 CHR (BITAND (p1, 16711680) / 65535)) enqueue_name,

14 DECODE (BITAND (p1, 65535), 1, \'Null\', 2, \'Sub-Share\',

15 3, \'Sub-Exclusive\', 4, \'Share\', 5, \'Share/Sub-Exclusive\',

16 6, \'Exclusive\', \'Other\') lock_mode

17 FROM v$session_wait WHERE sid = 96;

SID ENQ ENQUEUE_NAME LOCK_MODE

----- ---- ------------------------------ ----------

96 TX Transaction (RBS) Exclusive

enqueue in oracle 10g
enqueue in Oracle 10g

SQL> SELECT event, state, seconds_in_wait FROM v$session_wait WHERE sid = 143;

EVENT STATE SECONDS_IN_WAIT

----------------------------------- ------------------- ---------------

enq: TX - row lock contention WAITING 495

  • Separate events for separate TX issues:

SQL> SELECT name, parameter1, parameter2, parameter3

2 FROM v$event_name

3 WHERE name LIKE \'enq: TX%\';

NAME PARAMETER1 PARAMETER2 PARAMETER3

------------------------------ ------------- --------------- -------------

enq: TX - contention name|mode usn<<16 | slot sequence

enq: TX - row lock contention name|mode usn<<16 | slot sequence

enq: TX - allocate ITL entry name|mode usn<<16 | slot sequence

enq: TX - index contention name|mode usn<<16 | slot sequence

enqueue in oracle 10g12
enqueue in Oracle 10g
  • More descriptive parameter names, too:

SQL> SELECT name, parameter1, parameter2, parameter3

2 FROM v$event_name

3 WHERE name IN (\'enq: HW - contention\', \'enq: SQ - contention\');

NAME PARAMETER1 PARAMETER2 PARAMETER3

------------------------------ ------------- --------------- -------------

enq: HW - contention name|mode table space # block

enq: SQ - contention name|mode object # 0

wait event classes
Wait Event Classes
  • Every wait event belongs to one of 12 classes.
  • Classes can help point toward a root cause.
  • Almost 70% of all wait events belong to a class called “Other.”
  • Most of the wait events that occur frequently belong to wait event classes with helpful names.
wait class assignments
Wait Class Assignments

SQL> SELECT wait_class, name

2 FROM v$event_name

3 WHERE name LIKE \'enq: TX%\'

4 ORDER BY wait_class, name;

WAIT_CLASS NAME

--------------- ----------------------------------------

Application enq: TX - row lock contention

Concurrency enq: TX - index contention

Configuration enq: TX - allocate ITL entry

Other enq: TX - contention

v event name
v$event_name
  • Three new columns show which wait class a wait event belongs to:

SQL> DESCRIBE v$event_name

Name Null? Type

----------------------------------------- -------- -------------------

EVENT# NUMBER

EVENT_ID NUMBER

NAME VARCHAR2(64)

PARAMETER1 VARCHAR2(64)

PARAMETER2 VARCHAR2(64)

PARAMETER3 VARCHAR2(64)

WAIT_CLASS_ID NUMBER

WAIT_CLASS# NUMBER

WAIT_CLASS VARCHAR2(64)

v sql and v sqlarea
v$sql and v$sqlarea
  • Six new columns give more information about how time was spent executing a SQL statement:
    • application_wait_time
    • concurrency_wait_time
    • cluster_wait_time
    • user_io_wait_time
    • plsql_exec_time
    • java_exec_time
  • Times are in microseconds.
v sqlarea example
v$sqlarea Example
  • In session #1:

SQL> UPDATE testtab SET numcol = numcol + 1 WHERE ROWNUM < 1000;

  • In session #2:

SQL> UPDATE testtab SET numcol = numcol + 1 WHERE ROWNUM < 1000;

  • In session #1:

SQL> ROLLBACK;

  • In session #2:

SQL> ROLLBACK;

  • In session #3:

SQL> UPDATE testtab SET numcol = numcol + 1;

v sqlarea example19
v$sqlarea Example

SQL> SELECT sql_id, application_wait_time appl,

2 concurrency_wait_time concurr, user_io_wait_time user_io

3 FROM v$sqlarea

4 WHERE sql_text LIKE \'UPDATE testtab SET numcol%\';

SQL_ID APPL CONCURR USER_IO

------------- --------- --------- -----------

038m56cp4am0c 178500000 0 20000

fd5mxhdbf09ny 0 10000 105040000

SQL> SELECT sql_id, sql_text

2 FROM v$sqlarea

3 WHERE sql_id IN (\'fd5mxhdbf09ny\',\'038m56cp4am0c\');

SQL_ID SQL_TEXT

------------- -----------------------------------------------------------

038m56cp4am0c UPDATE testtab SET numcol = numcol + 1 WHERE ROWNUM < 1000

fd5mxhdbf09ny UPDATE testtab SET numcol = numcol + 1

v session wait history
v$session_wait_history
  • New view in Oracle 10g.
  • Similar to v$session_wait, but shows the last ten wait events for each session.
  • The seq# column is supposed to show the order in which the waits occurred, with 1 being the most recent wait:
    • Different from seq# in v$session.
    • Does not appear to work as documented (on our 10.1.0.3 system on Solaris).
v session wait history21
v$session_wait_history

SQL> DESCRIBE v$session_wait_history

Name Null? Type

----------------------------------------- -------- --------------------------

SID NUMBER

SEQ# NUMBER

EVENT# NUMBER

EVENT VARCHAR2(64)

P1TEXT VARCHAR2(64)

P1 NUMBER

P2TEXT VARCHAR2(64)

P2 NUMBER

P3TEXT VARCHAR2(64)

P3 NUMBER

WAIT_TIME NUMBER

WAIT_COUNT NUMBER

v session wait history example
v$session_wait_history Example

SQL> SELECT sid, seq#, event, wait_time, p1, p2, p3

2 FROM v$session_wait_history

3 WHERE sid = 154

4 ORDER BY seq#;

SID SEQ# EVENT WAIT_TIME P1 P2 P3

--- ---- ------------------------ ---------- ------ ------ ------

154 1 db file sequential read 28 4 3547 1

154 2 log buffer space 18 0 0 0

154 3 log buffer space 36 0 0 0

154 4 db file sequential read 0 4 3559 1

154 5 db file sequential read 0 4 1272 1

154 6 db file sequential read 0 4 3555 1

154 7 log buffer space 9 0 0 0

154 8 db file sequential read 0 4 3551 1

154 9 db file sequential read 6 4 1268 1

154 10 log buffer space 8 0 0 0

v session
v$session
  • All columns from v$session_wait have been added to v$session:
    • Saves us the effort of joining the two views..
  • New blocking_session, blocking_session_status columns:
    • blocking_session shows the SID of the session holding the resource blocking this session.
    • blocking_session_status contains ‘VALID’ when blocking_session is populated.
v session example
v$session Example
  • Prior to Oracle 10g:

SQL> SELECT s.sid, w.state, w.event, w.seconds_in_wait siw,

2 s.sql_address, s.sql_hash_value hash_value, w.p1, w.p2, w.p3

3 FROM v$session s, v$session_wait w

4 WHERE s.sid = w.sid

5 AND s.sid = 154;

  • Oracle 10g:

SQL> SELECT sid, state, event, seconds_in_wait siw,

2 sql_address, sql_hash_value hash_value, p1, p2, p3

3 FROM v$session

4 WHERE sid = 154;

another example
Another Example
  • Why is session 154 waiting? And who is blocking session 154?

SQL> SELECT sid, blocking_session, blocking_session_status block_status,

2 username, event, seconds_in_wait siw

3 FROM v$session

4 WHERE sid = 154;

BLOCKING

SID _SESSION BLOCK_STATUS USERNAME EVENT SIW

--- -------- ------------ -------- ------------------------------ ---

154 157 VALID TSUTTON enq: TX - row lock contention 318

v event histogram
v$event_histogram
  • New view in Oracle 10g.
  • Shows instance-wide summary wait event statistics like v$system_event, but provides a wait time histogram for each. Buckets:
    • Less than 1 mS.
    • 1 mS to 2 mS.
    • 2 mS to 4 mS.
    • 4 mS to 8 mS.
    • ... and so on
v event histogram27
v$event_histogram

SQL> DESCRIBE v$event_histogram

Name Null? Type

----------------------------------------- -------- ---------------------------

EVENT# NUMBER

EVENT VARCHAR2(64)

WAIT_TIME_MILLI NUMBER

WAIT_COUNT NUMBER

v event histogram example
v$event_histogram Example
  • How significant is the row lock contention on our system?

SQL> SELECT event, total_waits, time_waited, average_wait

2 FROM v$system_event

3 WHERE event = \'enq: TX - row lock contention\';

EVENT TOTAL_WAITS TIME_WAITED AVERAGE_WAIT

----------------------------- ----------- ----------- ------------

enq: TX - row lock contention 17218 2101966 122

  • Does the average wait of 1.22 seconds indicated by v$system_event paint an accurate picture?
v event histogram example29
v$event_histogram Example

SQL> SELECT event, wait_time_milli, wait_count

2 FROM v$event_histogram

3 WHERE event = \'enq: TX - row lock contention\';

EVENT WAIT_TIME_MILLI WAIT_COUNT

----------------------------- --------------- ----------

enq: TX - row lock contention 1 833

enq: TX - row lock contention 2 635

enq: TX - row lock contention 4 372

enq: TX - row lock contention 8 395

enq: TX - row lock contention 16 781

enq: TX - row lock contention 32 3729

enq: TX - row lock contention 64 3050

enq: TX - row lock contention 128 410

enq: TX - row lock contention 256 47

enq: TX - row lock contention 512 46

enq: TX - row lock contention 1024 37

enq: TX - row lock contention 2048 3

enq: TX - row lock contention 4096 6880

v system wait class and v session wait class
v$system_wait_class and v$session_wait_class
  • New views in Oracle 10g.
  • Show wait counts and total time waited since instance startup and session start.
  • Similar to v$system_event and v$session_event, but summarized by wait class.
  • Times are in centiseconds.
v system wait class and v session wait class31
v$system_wait_class and v$session_wait_class

SQL> DESCRIBE v$system_wait_class

Name Null? Type

----------------------------------------- -------- ---------------------------

WAIT_CLASS_ID NUMBER

WAIT_CLASS# NUMBER

WAIT_CLASS VARCHAR2(64)

TOTAL_WAITS NUMBER

TIME_WAITED NUMBER

SQL> DESCRIBE v$session_wait_class

Name Null? Type

----------------------------------------- -------- ---------------------------

SID NUMBER

SERIAL# NUMBER

WAIT_CLASS_ID NUMBER

WAIT_CLASS# NUMBER

WAIT_CLASS VARCHAR2(64)

TOTAL_WAITS NUMBER

TIME_WAITED NUMBER

v system wait class example
v$system_wait_class Example

SQL> SELECT wait_class, time_waited

2 FROM v$system_wait_class

3 ORDER BY time_waited DESC;

WAIT_CLASS TIME_WAITED

------------- -----------

Idle 777450022

System I/O 1261584

User I/O 116667

Configuration 116481

Application 72301

Other 12432

Commit 3496

Concurrency 319

Network 1

active session history
Active Session History
  • New MMNL background process samples v$session once each second.
  • Data captured on active sessions is available in v$active_session_history, usually for 1-4+ hours.
  • Automatic Workload Repository captures one out of every ten samples in its hourly snapshots.
active session history34
Active Session History

SQL> DESCRIBE v$active_session_history

Name Null? Type

----------------------------------------- -------- ---------------------------

SAMPLE_ID NUMBER

SAMPLE_TIME TIMESTAMP(3)

SESSION_ID NUMBER

SESSION_SERIAL# NUMBER

USER_ID NUMBER

SQL_ID VARCHAR2(13)

SQL_CHILD_NUMBER NUMBER

SQL_PLAN_HASH_VALUE NUMBER

SQL_OPCODE NUMBER

SERVICE_HASH NUMBER

SESSION_TYPE VARCHAR2(10)

SESSION_STATE VARCHAR2(7)

QC_SESSION_ID NUMBER

QC_INSTANCE_ID NUMBER

EVENT VARCHAR2(64)

EVENT_ID NUMBER

EVENT# NUMBER

SEQ# NUMBER

P1 NUMBER

P2 NUMBER

P3 NUMBER

WAIT_TIME NUMBER

TIME_WAITED NUMBER

CURRENT_OBJ# NUMBER

CURRENT_FILE# NUMBER

CURRENT_BLOCK# NUMBER

PROGRAM VARCHAR2(48)

MODULE VARCHAR2(48)

ACTION VARCHAR2(32)

CLIENT_ID VARCHAR2(64)

active session history35
Active Session History
  • v$active_session_history shows detailed wait information, current SQL statement, object/file/block information, and more.
  • When a wait that was sampled by ASH completes, Oracle fills in the time_waited column in the v$active_session_history row with the actual duration of the wait.
ash is always on
ASH is “Always On”
  • You may not have to turn on tracing or begin monitoring v$ views when users report a problem, because ASH is already sampling data.
  • In some cases you may be able to diagnose and resolve a problem on first detection, even if you learn of the problem after the fact.
    • You may not need to get users to reproduce the problem.
sampling versus collecting
Sampling versus Collecting
  • ASH samples v$session once each second. Very different from extended SQL trace, which collects data on every wait and every OCI call.
    • A session could encounter hundreds of waits in one second, and ASH will only capture data for one of them.
  • Use ASH to view aggregate data on many sessions over a period of time.
  • Don’t use ASH to count waits, get maximum wait times, or look at a short time period.
ash example
ASH Example

SQL> SELECT DECODE (session_state, \'WAITING\', event, NULL) event,

2 session_state, COUNT(*), SUM (time_waited) time_waited

3 FROM v$active_session_history

4 WHERE module = \'ARXENV\'

5 AND sample_time > SYSDATE - (2/24)

6 GROUP BY DECODE (session_state, \'WAITING\', event, NULL),

7 session_state;

EVENT SESSION_STATE COUNT(*) TIME_WAITED

------------------------------ ------------- -------- -----------

ON CPU 124 0

log file sync WAITING 2 52686

db file scattered read WAITING 2 28254

db file sequential read WAITING 1 6059

control file sequential read WAITING 1 9206

SQL*Net break/reset to client WAITING 1 9140

enq: TX - row lock contention WAITING 922 930864016

automatic workload repository
Automatic Workload Repository
  • Conceptually similar to Statspack.
  • Collects “snapshots” of system-wide performance statistics, plus ASH’s sampling of session activity.
  • You can generate activity reports using awrrpt.sql or Enterprise Manager interface.
  • Out of the box, Oracle 10g databases collect snapshots hourly and retain data for seven days.
awr management
AWR Management
  • Snapshot data is stored in SYS-owned tables in the SYSAUX tablespace.
  • Use dbms_workload_repository to:
    • Collect a snapshot on demand.
    • Purge snapshots.
    • Adjust snapshot interval.
    • Adjust snapshot retention period.
    • Disable AWR snapshot collection.
awr versus statspack
AWR versus Statspack
  • AWR benefits:
    • More tightly integrated into Oracle kernel, reducing snapshot collection overhead.
    • Snapshots include sampling of ASH data.
    • Data collected by AWR is accessible via views with names starting DBA_HIST.
    • DBA_HIST views are documented.
  • Statspack has been updated to be “10g aware”.
time model statistics
Time Model Statistics
  • New concept in Oracle 10g.
  • Two new views provide a more detailed picture of how Oracle spends time:
    • Separates out background and user processes.
    • Provides data not previously available, such as how much time was spent in PL/SQL execution.
  • Times are in microseconds.
time model statistics43
Time Model Statistics

SQL> DESCRIBE v$sys_time_model

Name Null? Type

---------------------------------------- -------- ---------------------------

STAT_ID NUMBER

STAT_NAME VARCHAR2(64)

VALUE NUMBER

SQL> DESCRIBE v$sess_time_model

Name Null? Type

---------------------------------------- -------- ---------------------------

SID NUMBER

STAT_ID NUMBER

STAT_NAME VARCHAR2(64)

VALUE NUMBER

time model statistics44
Time Model Statistics
  • Some important notes about these statistics:
    • Statistics do not include background processes unless “background” appears in the statistic name.
    • “DB time” shows elapsed time spent in Oracle calls. (Basically CPU time plus non-idle waits.)
time model statistics example
Time Model Statistics Example

SQL> SELECT stat_name, value / 1000000 seconds FROM v$sys_time_model

2 ORDER BY seconds DESC;

STAT_NAME SECONDS

------------------------------------------------ ----------

DB time 80970.190

sql execute elapsed time 75057.271

DB CPU 44448.628

background elapsed time 29333.160

PL/SQL execution elapsed time 8824.538

background cpu time 5170.311

parse time elapsed 1270.147

hard parse elapsed time 838.068

PL/SQL compilation elapsed time 176.731

sequence load elapsed time 112.334

connection management call elapsed time 44.644

failed parse elapsed time 11.946

hard parse (sharing criteria) elapsed time 5.579

hard parse (bind mismatch) elapsed time 4.610

failed parse (out of shared memory) elapsed time 0.000

Java execution elapsed time 0.000

inbound PL/SQL rpc elapsed time 0.000

tracing improvements
Tracing Improvements
  • Enabling extended SQL trace in another session is now more convenient.
  • Tracing sessions in a connection pooling or shared server environment is no longer impractical.
  • New dbms_monitor package offers these two benefits and more.
tracing prior to oracle 10g
Tracing Prior to Oracle 10g
  • Tracing sessions in Oracle 9i and earlier had annoyances:
    • dbms_support usually missing or not installed.
    • dbms_system.set_ev not officially supported.
    • ALTER SESSION SET EVENTS to set 10046 event has a syntax hard (for some of us) to remember.
easier tracing in oracle 10g
Easier Tracing in Oracle 10g
  • Control tracing of your own session:

EXECUTE dbms_monitor.session_trace_enable (waits=>TRUE, binds=>TRUE);

EXECUTE dbms_monitor.session_trace_disable ();

  • Control tracing of another session:

EXECUTE dbms_monitor.session_trace_enable (session_id=>153, waits=>TRUE);

EXECUTE dbms_monitor.session_trace_disable (session_id=>153);

  • Tracing sessions in Oracle 10g is easier because dbms_monitor is provided and installed in every Oracle 10g database by default.
tracing prior to oracle 10g49
Tracing Prior to Oracle 10g
  • Straightforward if session being traced uses dedicated server connection.
  • Tracing session using shared server architecture leads to multiple trace files that have to be merged manually.
  • Tracing an end-user session that does not map to one Oracle session (eg: connection pooling or multiplexing) is not practical.
new tracing features in 10g
New Tracing Features in 10g
  • Tracing can be enabled for sessions with a specific client identifier:

EXECUTE dbms_session.set_identifier (\'client identifier\');

EXECUTE dbms_session.clear_identifier ();

  • Tracing can be enabled for sessions with specific service / module / action combination:

EXECUTE dbms_application_info.set_module (\'module name\', \'action name\');

EXECUTE dbms_application_info.set_action (\'action name\');

  • Trace data split over multiple trace files can be merged into one trace file for TKPROF processing:

$ trcsess output= [clientid=] [service=] [module=] [action=] [session=]

connection pooling example
Connection Pooling Example
  • Application server connection pooling code:

EXECUTE dbms_session.set_identifier (\'session_id from application table\');

...do the work for this end user session...

EXECUTE dbms_session.clear_identifier ();

  • Trace the end-user session assigned session_id 12345 in the application’s sessions table:

SQL> EXECUTE dbms_monitor.client_id_trace_enable -

> (client_id=>\'12345\', waits=>TRUE, binds=>TRUE);

  • Consolidate trace data into one trace file suitable for use by TKPROF:

$ cd $ORACLE_BASE/admin/$ORACLE_SID/udump

$ trcsess output=mytracefile.trc clientid=12345

twelve oracle 10g enhancements52
Twelve Oracle 10g Enhancements
  • More descriptive wait event names
  • Wait event classes
  • v$event_name new columns
  • v$sql / v$sqlarea new columns
  • v$session_wait_history
  • v$session new columns
  • v$event_histogram
  • v$system_wait_class / v$session_wait_class
  • Active Session History (ASH)
  • Automatic Workload Repository (AWR)
  • Time model statistics
  • Improved session tracing
wrapping up
Wrapping Up
  • Oracle 10g includes many enhancements to the wait event interface that should make performance management using wait event methodologies easier than ever.
  • Some are just conveniences:
    • More descriptive event names, wait event classes, dbms_monitor.session_trace_enable...
  • Some provide data previously unavailable:
    • New v$sql columns, time model statistics, v$event_histogram...
white paper54
White Paper
  • Contains additional detail we didn’t have time to cover today.
  • Includes a handy reference list of all Oracle 10g wait events, wait classes, and wait event parameters.
  • Download: www.dbspecialists.com/presentations
contact information
Contact Information

Terry Sutton and Roger Schrag

Database Specialists, Inc.

388 Market Street, Suite 400

San Francisco, CA 94111

Tel: 415/344-0500

Toll-free: 888/648-0500

www.dbspecialists.com

[email protected]

[email protected]

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