© 2011 IBM CorporationMay 2, 2023

Improve the Speed and Performance

John F. Miller III, IBMScott Lashley, IBM

Information Management – IDS 11

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Network Messaging

Information Management – IDS 11

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Optimizing Database Network Messaging

• Data Buffer Management• Optimize Open-Fetch-Close (OPTOFC)• Deferred Prepare• Auto Free

Information Management – IDS 11

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Examining SQL Network Messages

– Network messages sent between the application and the database engine to accomplish SQL operations

PREPARE stmt FROM “select * from t where a > ?”;

DECLARE cursor_1 from :stmnt;OPEN cursor_1 USING var_1;FETCH cursor_1 into results_1;CLOSE cursor_1;FREE cursor_1;FREE stmt;

Information Management – IDS 11

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PREP/DEC Small Sent - Medium ReturnedOPEN Small Sent - Medium ReturnedFETCH Small Sent - Medium ReturnedCLOSE Small Sent - Small ReturnedFREE Small Sent - Small Returned

Normal Message Traffic– 128 KB of data returned by the select– No blob data and rows smaller than 4KB

Total number of messages sent = 72

32x

Information Management – IDS 11

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Improving SQL Network Messages

– FET_BUF_SIZE Set the buffer size for the fetch/insert buffers Size is specified in bytes up to 32KB Requires no application changes Yields similar performance as fetch array

– OPTOFC – Optimize Open Fetch Close Requires only error checking changes Delays sending the open until the first fetch is requested

by the application The engine will close the cursor when the last row is

processed

– Deferred Prepare Control whether a client process postpones sending a

PREPARE statement to the database server until the OPEN or EXECUTE statement is sent

– Auto Free Frees the cursor when the cursor is closed

Information Management – IDS 11

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PREP/DEC Small Sent - Medium ReturnedOPEN/FETCH Medium Sent - 32KB ReturnedFETCH Small Sent - 32KB ReturnedFETCH/CLOSE Medium Sent - 32KB Returned FREE Small Sent - Small Returned

2x

Total number of messages sent = 12

OPTOFC Message Traffic

OPTOFC enabledFetch buffer set at 32KB

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PREP/DEC Small Sent - Medium ReturnedOPEN Small Sent - Medium ReturnedFETCH Small Sent - Medium ReturnedCLOSE Small Sent - Small Returned

Total number of messages sent = 8

Small Select Statements Traffic Improvement

PREP/DEC/OPEN/FETCH/CLOSE Medium Sent - 32KB Returned

Total number of messages sent = 2

OPTOFC enabled Fetch buffer set at 32KB Defer Prepare enabled

Information Management – IDS 11

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Are My Application Using OPTOFC?

session effective #RSAM total used dynamic id user user tty pid hostname threads memory memory explain 145 informix - 20 30096 talo 1 274432 270896 off

tid name rstcb flags curstk status232 sqlexec 44d28d78 Y--P--- 12272 cond wait cmd_cond -

Memory pools count 2name class addr totalsize freesize #allocfrag #freefrag 145 V 46853040 270336 2728 259 6

name free used name free used overhead 0 6576 resident 0 72 scb 0 144 opentable 0 8656 filetable 0 1344 ru 0 600 misc 0 1088 log 0 16536

sqscb infoscb sqscb optofc pdqpriority sqlstats optcompind directives45ce0028 4620c028 0 0 0 2 1

Sess SQL Current Iso Lock SQL ISAM F.E. Id Stmt type Database Lvl Mode ERR ERR Vers Explain 145 EXEC PROCEDURE sysadmin CR Not Wait 0 0 9.24 Off

Information Management – IDS 11

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Network Performance Improvements

Caching network services

Multiple listener threads for a single server name

Multiple file descriptor servers

Previous network improvements– Dynamic start and stop of listener

threads– Pre-allocate users session

Information Management – IDS 11

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Network Performance - Caching Network Services Database caching of Host, Services, Users and

Groups Avoids going to the operating system for each

network call Administrator defined timeout value set for

network caches ONCONFIG example

NS_CACHE host=900,service=900,user=900,group=900

Each cache is dynamically configurable

Information Management – IDS 11

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Network Performance – Multiple Listeners

Able to define multiple listener threads for a single DBSERVERNAME and/or DBSERVERALIAS

Add the number of listeners to the end of the alias EXAMPLE

– To start three listener threads for the idsserver– Modify the ONCONFIG as follows

DBSERVERNAME idsserver-3

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Information Management – IDS 11

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Network Performance Results

My simple network performance tests– 200 users connecting and disconnecting

Connection throughput on an AIX server improved by 480%

Connection throughput on a Linux server improved by 720%

Computer Type WithoutImprovements

Utilizing Improvements

AIX 64 2m 5s 27sLinux 64 10m 11s 1m 20s

Information Management – IDS 11

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