sqlcl - sql*plus with benefits plus calling plsql from sql ...alias myalias=(pl)sql defines alias...

SQLcl - SQL*Plus with Benefitsplus

Calling PLSQL from SQL since 12c

Erik van Roon

OUG Scotland 2019

Who Am I?

• Erik van Roon

• Originally analyst of microbiology and biochemistry

• Oracle developer since 1995, self-employed since 2009

• Most of my work takes place inside the database

• *Playing* with APEX since 2008

• Did several successful major datamigration projects

: [email protected]: www.evrocs.nl : @evrocs_nl

mailto:[email protected]

http://www.evrocs.nl/

SQLcl(SQL*Plus with benefits)

What is SQLcl?

• a command line Interface like SQL*Plus

• Built in Java by the SQL-Developer team

• Built around the SQLDev Java library for executing SQL

• Runs anywhere a JRE is available(Windows, Linux, Mac,…)

Q: Will it replace SQL*Plus?A: No! “SQL*plus will always exist alongside SQLcl”

How do you get SQLcl?

• Included in SQL Developer

• So, also in DBMS installation(Recent versions)

• Available from Oracle Software Downloadshttp://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html

Only place it’s missing now is the Oracle Client Software

http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html

Installation

Pay attention

This is really hard

• Go to the download pagehttp://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html

• Login with your OTN account

• Accept the license agreement

• Click 'Download’

• Save the zip file

• Unzip the zipfile

http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html

• Multiple concurrent versions are possiblejust unzip to different directories

• No need for

–Oracle client installation

– tnsnames.oraThough you can use one of course

– JDK (Though you do need a JRE >= 1.8)

Release notes 19,1 say“Java versions 9 and 10 are not yet supported”

Jeff Smith blog (April 29 2019) says“You can already use Java 11 for Oracle REST Data Services and SQLcl”

Disadvantages?

Bugs

Example: Since 18.2 serveroutput with “format wrapped” causes

extra empty lines in output when script has comments

However:

• SQLcl is frequently updated

• SQL*Plus has bugs too(e.g. unpatched version in 12.2 ignores SQLPATH)

SQL*Plus SQLclScript

Disadvantages?

Startup is slower dan sqlplus

However:• On average computer

difference not enough to worry about• On my laptop:

Start Sql*Plus < 1 secStart SQLcl 3 - 4 sec

Disadvantages?

Supports a lot but not everything SqlPlus

19.1, "SQL*Plus List of Unsupported Commands and Features":- REPHEADER- REPFOOTER

“Column” accepts entire SqlPlus syntax, But apart from “new_value” everything is ignored.

SqlPlus SQLcl

Find the differences

Help

Run help to get information on (almost) all functionality

The asterisks indicate which are unique for sqlcl

Help is (really) good, but not perfect:• Modifiers for Bridge not mentioned in help

• Seterrorl is not a command. “help seterrorl” leads to help for

“set errorlogging …”which is missing in “help set” :-b

Command Completion

Start typing a statement and hit [Tab]

‘Hits’ are displayed and if all hits have a common start (in this case EVROCS_), it is already filled in…

➢ Query needs to be ‘sensible’:

SELECT FROM EVR [Tab]

Won’t work

Command Completion, the motion picture

History

show history Shows current history settings, *not* the history itself

history will show a list of executed statements, 1 statement per line

history full list of executed statements, as entered (also multiline)

history usage same as 'history' but also displays number of executions

history time same as 'history' but also displays execution time

history clear erases the entire history buffer

history (entry number) loads statement with given entry number into the sqlcl buffer

Also: just browse through your history using arrow-up & arrow-downPer statement!! Not per entered line as in sqlplus.

History

- is enabled (haven't found a way to disable)- Doesn't store duplicates of statements, each unique statement is stored only once- Stores multiline statements as one entry, not individual lines- stores a maximum of 100 statements, increase/decrease with for example:

set history limit 500set history limit default to return to default behavior

- Doesn't store failed queries, so no pollution, but also no correcting of typos. Toggle this behavior with

set history fails 10 to have a maximum of 10 failed statements in historyset history nofails to go back to default behavior

- Does not store show, history, connect and set commands. Change this list with for example:

set history blacklist show,history,connect,set,commit,rollback

History

Warning:

EXEC statements are expanded to plsql blocks in history

Exec ended with semicolon (don’t!)leads to invalid statement in history due to extra semicolon

command line editing

Edit complete statements (not just lines) without external editor

• Use up & down keys to get to statement of interest in history

• Use Left key to enter editing mode

• Modify statement however you want

• Hit CTRL-R to run the modified statement

command line editing, the motion picture

Sqlformat

formats the output of all following sql statements

set sqlformat [format]

All formats are also available as comments in a query

(like they are in SQLDev):

select /*csv*/ * from user_tables;

Sqlformat - Formats

• csv Output as comma separated values

• json Output as json

• fixed Fixed width columns, double-quoted values

• html Output as html

• insert Output as insert statements

• default Clears any set sqlformat

• xml Output as xml

• loader Pipe (|) delimited values

• delimited Like csv, but separator and delimiters can be defined

• ansiconsole Pretty output (see later)

Sqlformat – delimited

Returns character separated values.

Separator and delimiters can be defined in parametersSet sqlformat delimited [delimiter [encloser-left [encloser-right]]]

• Delimiter can not be a non-printable character (like Tab)

• Enclosers can not be empty, defaults to double quote

Sqlformat – Ansiconsole

Output is formatted more readable

Column widths are based on actual data and headers

Sqlformat – Ansiconsole

Some enhancements possible:

• Data containing EndOfLine not handled correctly yet

• If statement edited and run with [enter], header starts at last line of statement

Sqlformat – Ansiconsole Number format

Set a default format for your number columns

set sqlformat ansiconsole [format]

Format as in Java (link to webpage is in help text)

Sqlformat – Ansiconsole Data Highlight

Highlight data returned by queries

Define rules in a json file like:

{"highlights":

[

{"type":"startWith" ,"test":"ERO" ,"color":"INTENSITY_BOLD,YELLOW"},

{"type":"endWith" ,"test":"GTT" ,"color":"BLUE" },

{"type":"contains" ,"test":"SNAPSHOT" ,"color":"CYAN" },

{"type":"exact" ,"test":"CUSTOMERS" ,"color":"GREEN" },

{"type":"regex" ,"test":".*[0-9].*" ,"color":"MAGENTA" }

]

}

Sqlformat – Ansiconsole Data Highlight

Does *not* work in Windows ‘DosBox’/cmd-window

Does work in alternativesLike ConEMU

Apex

Command Apex lists all applications

Apex export

Help just says: apex export <app id> - Exports the application which could be combined

with spool for writing to a file

But typing in rubbish like apex export 0 alkjsdhfkjh

Shows there is more

Info(rmation)

Info / Information shows information about most object types

For a table it shows regular 'desc' information plus:

• table analysis information (last analyzed, row count, ...)

• table and column comments

• column default values

• indexes

• foreign key constraints

Info(rmation)

Info+

Info+ (currently there is no Information+)

When used for tables the column comments are replaced by some statistics

• low value

• high value

• number of distinct values

• type of histogram

Alias

alias show list of currently loaded aliases

alias list same as "alias" but includes alias descriptions

alias list MyAlias Shows the statement that MyAlias is an alias for

alias MyAlias=(pl)sql Defines alias MyAlias for some sql or plsql

alias MyAlias=@script Defines alias MyAlias for some sql script

alias drop MyAlias Removes alias MyAlias from memory

alias save [filename] Saves ALL currently loaded aliases to filenamedefault file is %APPDATA%\sqlcl\aliases.xml

alias load [filename] Loads aliases from filenamedefault file is %APPDATA%\sqlcl\aliases.xmlAppends to already loaded aliases, overwrites already existing ones

Assign a user-defined name to sql, plsql and scripts

Unless ‘save’ is used, alias is for the duration of the SQLcl session

Alias - Example

PLSQL block, including bind variables

Alias - Case

Watch out aliases are case-sensitive

Alias – Host command

Even host commands can be aliasedProvided you end them with a semicolon

Working directory

It's the little things that make life good

PWD (Print Working Directory)• displays the current working directory, like the linux/unix pwd command

• saves user one keystroke (pwd instead of !pwd or $dir)

• saves windows users a lot of unwanted output compared to $dir

CD (Change Directory)• changes the working directory while inside SQLcl

• Even to other disk, without the usual dos /d parameter

• No more need to exit, change directory and start a new commandline

Files

Find filenameIs supposed to list all occurrences of filename in the SQLPATH

But lists all in:

• SQLPATH

• Working directory

• All subdirs of working dir

• All subdirs of sqlpath dirs

No wildcards allowed

Which filenamedisplays the pathname of the script that will be executed if called with @filename

DDL

Basically just shorthand for dbms_metadata.get_ddl

ddl object_name [object_type] [save filename]

Behavior can be altered with dbms_metadata like:exec dbms_metadata.set_transform_param

(dbms_metadata.session_transform, 'CONSTRAINTS_AS_ALTER', true);

exec dbms_metadata.set_transform_param

(dbms_metadata.session_transform, 'SEGMENT_ATTRIBUTES' , false);

If used often: make aliases for such transforms.

Bridge

Bridge gets data from a remote connection into a local table without needing a database link

Similar to sqlplus command "copy".

bridge targettable as "jdbcURL" (query)[modifier];

jdbcURL : jdbc:oracle:thin:username/password@host:port/servicename

e.g. : jdbc:oracle:thin:ero/ero@localhost:1521/evrocs

Targettable is created if it does not exist.

Bridge – modifier

The modifier is not in the help yet!!!

(= no modifier) Always do create target table. Ora-00955 if it already exists

replace Drop target table if it exists, then re-create it and add the data

append Add the data of the query to possibly existing data in target table

truncate Truncate the target table before adding the data

skip If table exists: it does nothing (reports "table already exists, inserted 0 rows")

If table doesn’t exist: will create it and add the data

Modifier HAS (!!) to be directly after closing bracket after query

Repeat

Repeat runs the statement in the buffer

For a requested number of times With a requested wait time between executions

repeat number_of_times seconds_between_executions

The wait time can not be more then 120 seconds

Repeat – The Motion Picture

TIP

SQLcl uses same SQLPATH environment variable as SqlPlus

So• will execute the same (g)login.sql

So what?• sqlcl-specific stuff in login.sql will cause

errors when starting sqlplus• sqlplus-specific stuff in login.sql that is not

(yet/fully) supported in sqlcl will cause errors when starting sqlcl

But: easily fixed….

1. All common settings in x:\login\common_login.sql

Fix common SQLPATH

2. Create x:\login\PLUS\login.sql• All SQLPLUS specific settings• @@..\common_login.sql

3. Create x:\login\CL\login.sql• All SQLCL specific settings• @@..\common_login.sql

4. Create batchfiles sp.bat & sc.bat• Add the login directory to SQLPATH• Run the executable passing all parameters

Fix common SQLPATH

x:\login\common_login.sql x:\login\PLUS\login.sql

x:\login\CL\login.sql

sp.bat sc.bat

TIP

In SQLPLUS language of messages controlled by NLS_LANG

In SQLcl the language is determined by OS language

To change this, add to previously mentioned batch file:

set JAVA_TOOL_OPTIONS=-Duser.language=en -Duser.region=US

Replace ‘en’ and ‘US’ as desired

TIP

By default error messages show more than in sqlplus

If you don’t like that:

set classic on

TIP

Watch out:

set feedback off

Also suppresses all error messages

Release notes of 18.3 say:

But still present in 19.1

Calling userdefined functions

from SQL queries

got faster in Oracle 12c

The problem:

– SQL and PLSQL have their own engines

–Calling one from the other introduces context switches

–Doing so often has a performance impact

Speeding up SQL calls from PLSQL involves:

–Doing as little individual SQL statements as possible

–Doing Bulk Operations

• Bulk Collect

• Forall

Speeding up PLSQL calls from SQL involves:

Pre 12c: Do it as little as possible

i.e. Try to do it in pure SQL

12c and beyond:

–defining plsql functions in Subquery Factoring (the with clause)

–defining functions using PRAGMA UDF

PLSQL in Subquery Factoring

Example of a function in the with clause:withfunction digit_sum(pi_integer in integer)return integeris

c_as_string constant varchar2(15) := to_char(pi_integer,'fm999999999999999');l_result integer := 0;

beginfor i_pos in 1 .. length(c_as_string)loop

l_result := l_result + to_number(substr(c_as_string, i_pos, 1));end loop;return (l_result);

end;--select object_id "Object ID", digit_sum (object_id) "Sum Of Digits"from user_objectsfetch first 4 rows only/

Must be “/”, not “;” in SQL*Plus and SQLcl


Result:

Warning:

If a function is declared right there in the querythe mistake is easily made to think it’s part of the query

However:

This plsql is NOT part of the read consistencyTrue for ANY PLSQL called from SQL

If the PLSQL is not defined in the top-level query, but for example:

– In any subquery

– In the query of an “insert into .. select from ..”

– In the “using()” query of a merge statement

We need to ‘warn’ the compiler that it will run into PLSQL:

Use the hint:

/*+ WITH_PLSQL */

For example PLSQL defined in select of an insert:insertinto my_table (col1, col2)withfunction do_somethingreturn ....isbeginreturn (...);

end;select source_data, do_somethingfrom other_table/

will result in ORA-32034: unsupported use of WITH clause

insert --+ with_plsqlinto my_table (col1, col2)with function do_something return .... is begin return (...);

end; select source_data , do_something from other_table /

will be successful

Syntax errors can lead to pretty useless error messages.Often the message will just be:

ERROR at line ###: ORA-00905: missing keyword

where the line number is the line where the function begins

Advise: develop the PLSQL in an anonymous block until syntactically correct, before putting it into the with-clause

Procedures can also be defined in the With-clause!But can obviously only be executed from other plsql in with clause, not the query.

with

procedure proc1(pio_1 in out number)

isbeginpio_1 := power(pio_1 , 2);dbms_output.put_line ('Squared number '||to_char(pio_1));

end proc1;--

function func1(pi_1 in integer)return numberisl_value_1 number := pi_1;

begin

proc1 (pio_1 => l_value_1);

return (l_value_1);end func1;

select level value

, func1 (pi_1 => level) calculated_value

from dualconnect by level <= 5/


Unfortunately, Function Result Cache can not be used

with

function f (p in integer)

return varchar2

result_cache

as

begin

return (p);

end;

--

select function_input

, f (function_input) function_output

from (select mod(level,2) function_input

from dual

connect by level <= 4

)

/

The function *can* be declared deterministic without error messages, however .....

In 12.1No error messages, But deterministic is ignored

In 12.2 and 18:Sometimes it works

Sometimes it's ignoredAt least one case gives wrong results

In 19 (livesql: https://livesql.oracle.com):Back to 12.1 behavior: always ignore deterministic

So, Best bet: Don’t use deterministic with this

https://livesql.oracle.com/

Behavior as expected in 12.2 & 18withfunction f (p in integer)

return integerdeterministicasbegindbms_output.put_line ('Executed for value '||p);return (p);

end;--select function_input, f (function_input) function_outputfrom (select level function_input

from dualconnect by level <= 4union allselect level function_inputfrom dualconnect by level <= 4

)/

Behavior *not* as expected in 12.2 & 18

withfunction f (p in integer)

return varchar2deterministicasbegindbms_output.put_line ('Executed for value '||p);return (p);

end;--select function_input, f (function_input) function_outputfrom (select level function_input

from dualconnect by level <= 4union allselect level function_inputfrom dualconnect by level <= 4

)/

Example of *wrong* deterministic results in 12.2 & 18

with

function f (p in integer)

return integer

deterministic

as

begin

dbms_output.put_line

('Executed for value '||p);

return (p);

end;

--

select mod(level,2) function_input

, f (mod(level,2)) function_output

from dual

connect by level <= 4

/

In 19 (LiveSql) correct results, but deterministic ignored

Scalar Subquery Caching *does* work in 12.1Not in 12.2, 18, 19

withfunction f (p in integer)return varchar2asbegindbms_output.put_line ('Executed for value '||p);return (p);

end;select function_input, (select f (function_input)

from dual) function_output

from (select level function_inputfrom dualconnect by level <= 4union allselect level function_inputfrom dualconnect by level <= 4)

/

12,1

12,2

There’s a bug, causing ora-600 in *a very specific case*(Bug 22654079)

If:

1. You have a merge statement

2. AND there's plsql in the with-clause of the 'using' query

3. AND the statement uses bind variables

THEN:

ORA-03113: end-of-file on communication channel

Example of bug 22654079

merge /*+ with_plsql */into ero_test_merge_bug tgtusing (with

function f (p in integer)return integerisbeginreturn p * 10;

end;--select id, f (id) valuefrom ero_test_merge_bugwhere id = :my_id

) srcon (tgt.id = src.id)when matchedthenupdate set tgt.value = src.value

when not matchedtheninsert values (src.id, src.value)

/

PLSQL in the with clause is not supported by PLSQL (yet?)

Declaring a cursor with such a query leads, once again to

"ORA-00905: missing keyword“

Work-around: dynamic sql *does* work

But: ..............................................

If already in plsql anyway, why not declare the function separately with pragma udf?

Wait! So we have an alternative?

Of course!

There's the possibility to add a

Pragma UDF

to a standalone or packaged function.

Instructs the compiler that the function will be used within SQL.

Documentation says:

"...which might improve its performance"

How do we apply this?

create or replace function blabla

return ...

is

pragma udf;

begin

....

return ...

end;

/

Advantages compared to with-clause functions

– no need for with_plsql hint in any situation

– debugging the plsql is easier: syntax errors give ‘usual’ messages

– function result cache can be used

– Deterministic can be used, behaves like deterministic function in with clause, except that the query that gives wrong results when using a deterministic function in with-clause, now works correct

– Scalar Subquery Caching also works

– Can be used without problem in merge statements containing bind variables

– reuse of function in other queries possible

Disadvantage compared to with-clause functions

– You need to create an object (function/package) in the database.

You may not want to do that (e.g. for a script in your toolkit for daily development/dba work)

You may not be allowed to do that (e.g. for a check script you run on different databases, among which Production)

– Performance gain (as we will see later) is hard to predict

How do these two features affect performance?

Measure runtime of test executions:

– For combinations of input parameter- & return datatypes

– Run each test 11 timesignore result of first runcalculate average and standard deviation for the others

– Flush the shared pool after each (11 executions of a) test

– Tests were executed on a table of 5 million rows

Plsql_optimize_level:

Tests have been run for all levels (0,1,2,3).

No significant differences in performance for any specific test noticed when running with either of the optimize levels.

Following results were obtained with plsql_optimize_level 2

The following tests have been executed:

Test name Description

PLAIN SQL Sql statement without plsql

REGULAR Sql statement calling a regular database function

WITH Sql statement calling a function in the with clause

UDF Sql statement calling a UDF database function

WITH WRAPS REGULAR Function in the with clause calls a regular DB function

WITH WRAPS UDF Function in the with clause calls a UDF DB function

UDF WRAPS REGULAR Sql calls UDF DB function which calls regular DB function

REGULAR WRAPS REGULAR Sql calls regular DB function which calls a regular DB function

UDF WRAPS UDF Sql calls UDF DB function which calls UDF DB function

REGULAR WRAPS UDF Sql calls regular DB function which calls UDF DB function

Test : Regular PLSQL (= Baseline)

Parameter Return Runtime Std Dev 95% confidence Ratio

Number Number 5,681 0,090 0,056 100

Varchar2 Number 6,856 0,049 0,030 100

Date Number 7,124 0,246 0,152 100

Number Varchar2 5,805 0,050 0,031 100

Varchar2 Varchar2 7,127 0,117 0,073 100

Date Varchar2 7,224 0,093 0,058 100

Number Date 10,201 0,164 0,102 100

Varchar2 Date 10,549 0,367 0,227 100

Date Date 10,254 0,243 0,151 100

Binary Float Binary Float 7,173 0,064 0,040 100

Binary Double Binary Double 7,142 0,125 0,077 100

Test : Plain SQL (No PLSQL Calls)


Number Number 1,394 0,013 0,008 25

Varchar2 Number 1,372 0,017 0,011 20

Date Number 1,369 0,036 0,022 19

Number Varchar2 1,415 0,025 0,015 24

Varchar2 Varchar2 1,434 0,016 0,010 20

Date Varchar2 1,392 0,033 0,020 19

Number Date 1,549 0,021 0,013 15

Varchar2 Date 1,512 0,009 0,006 14

Date Date 1,454 0,019 0,012 14



Test : PLSQL in With Clause


Number Number 2,387 0,138 0,086 42

Varchar2 Number 2,265 0,017 0,011 33

Date Number 2,315 0,015 0,009 32

Number Varchar2 2,728 0,050 0,031 47

Varchar2 Varchar2 2,782 0,055 0,034 39

Date Varchar2 2,755 0,035 0,022 38

Number Date 5,051 0,061 0,038 50

Varchar2 Date 5,026 0,153 0,095 48

Date Date 4,917 0,083 0,051 48



Test : Database Function Using Pragma UDF


Number Number 2,095 0,010 0,006 37

Varchar2 Number 6,913 0,033 0,020 101

Date Number 6,973 0,054 0,033 98

Number Varchar2 2,232 0,012 0,007 38

Varchar2 Varchar2 7,375 0,082 0,051 103

Date Varchar2 7,384 0,135 0,084 102

Number Date 10,152 0,076 0,047 100

Varchar2 Date 10,248 0,069 0,043 97

Date Date 9,985 0,064 0,040 97



Test : With clause calling a regular function


Number Number 3,114 0,022 0,014 55

Varchar2 Number 3,111 0,020 0,012 45

Date Number 5,516 0,026 0,016 77

Number Varchar2 3,480 0,048 0,030 60

Varchar2 Varchar2 3,623 0,036 0,022 51

Date Varchar2 6,006 0,115 0,071 83

Number Date 5,834 0,210 0,130 57

Varchar2 Date 5,682 0,058 0,036 54

Date Date 7,493 0,052 0,032 73



Test : With clause calling a UDF function


Number Number 3,106 0,024 0,015 55

Varchar2 Number 3,150 0,008 0,005 46

Date Number 5,796 0,088 0,055 81

Number Varchar2 3,478 0,050 0,031 60

Varchar2 Varchar2 3,790 0,330 0,205 53

Date Varchar2 6,179 0,072 0,045 86

Number Date 5,972 0,084 0,052 59

Varchar2 Date 5,922 0,052 0,032 56

Date Date 7,610 0,079 0,049 74



Test : a regular function calling a regular function


Number Number 6,563 0,084 0,052 116

Varchar2 Number 7,855 0,051 0,032 115

Date Number 10,930 0,102 0,063 153

Number Varchar2 7,141 0,052 0,032 123

Varchar2 Varchar2 8,501 0,051 0,032 119

Date Varchar2 11,432 0,247 0,153 158

Number Date 11,065 0,239 0,148 108

Varchar2 Date 11,610 0,106 0,066 110

Date Date 13,117 0,125 0,077 128



Test : a regular function calling a UDF function


Number Number 6,461 0,066 0,041 114

Varchar2 Number 7,974 0,064 0,040 116

Date Number 10,809 0,046 0,029 152

Number Varchar2 7,075 0,068 0,042 122

Varchar2 Varchar2 8,837 0,428 0,265 124

Date Varchar2 11,670 0,112 0,069 162

Number Date 11,106 0,092 0,057 109

Varchar2 Date 11,394 0,180 0,112 108

Date Date 13,647 0,444 0,275 133



Test : a UDF function Calling a regular function


Number Number 2,870 0,019 0,012 51

Varchar2 Number 8,191 0,246 0,152 119

Date Number 10,921 0,130 0,081 153

Number Varchar2 3,250 0,040 0,025 56

Varchar2 Varchar2 8,497 0,087 0,054 119

Date Varchar2 11,412 0,093 0,058 158

Number Date 11,436 0,223 0,138 112

Varchar2 Date 11,614 0,127 0,079 110

Date Date 13,293 0,197 0,122 130



Test : a UDF function calling a UDF function


Number Number 3,007 0,025 0,015 53

Varchar2 Number 8,017 0,087 0,054 117

Date Number 10,897 0,113 0,070 153

Number Varchar2 3,221 0,033 0,020 55

Varchar2 Varchar2 8,635 0,108 0,067 121

Date Varchar2 11,517 0,098 0,061 159

Number Date 11,368 0,145 0,090 111

Varchar2 Date 11,513 0,125 0,077 109

Date Date 13,234 0,099 0,061 129



Conclusions from these performance tests

These tests have NOT been run with YOUR real life functions / queriesThese tests have NOT been run on YOUR hardwareThese tests have NOT been run on YOUR version of YOUR database with YOUR patches


Plain SQL without PLSQL • No surprise:

Plain SQL without PLSQL is ‘always’ fastest

Datatypes • Parameter- and (mainly) Return datatypes have an impact on runtime

Even with regular functions:returning number takes half the runtime of returning dates


SQL, calling UDF database function • Faster than calling regular database function

but only for specific datatype combinations

Mainly when handling numeric datatypes

• If it is faster than regular, it’s also a bit faster then a function in the with clause (~10-20%)

Functions in the with clause• Appear to always be faster than regular functions

Regardless of used datatypes


Function in the with clause that calls a database function• Will be faster than calling the database function regularly

It makes no real difference if the database functionis a regular or UDF function

So, may be a nice way to speed up database functions you don’t control For example: executing functions in dbms_* packages


UDF function calling another function • Whether the second function is regular or UDF has

almost no impact on performance in this case

Regular function calling another function • Whether the second function is regular or UDF has

almost no impact on performance in this case

(Pipelined) Table Function, PTF

A quick (lot less extensive) test for table function

- Just for:parameter = number return = Nested Table of two numbers

- Compare regular pipelined table function with UDF version

- Run both 11 times, ignore the first result

- Flush the shared pool after each (11 executions of a) test

- Tests were executed so the functions return 5 million rows

(Pipelined) Table Function, PTF

Results:

So, no difference at all

Comment by Bryn Llewellyn:

“Correct, and as expected because pipelined table functions are already, and always have been optimized for use in sql queries”

Test Runtime Std Dev 95% confidence Ratio

REGULAR PTF 2,939 0,043 0,027 100,000

UDF PTF 2,947 0,047 0,029 100,000

“People often say that there are no stupid questions.They are wrong. They actually do exist.But it takes a lot more time and energy to correct a stupid mistake than it takes to answer a stupid question, so please ask your stupid questions.”

a wise teacher who didn't just teach me physics

sqlcl - sql*plus with benefits plus calling plsql from sql ...alias myalias=(pl)sql defines alias...

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