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From the Oracle9i Data Warehousing Guide manual:

[NO]LOGGING Clause

 The [NO]LOGGING clause applies to tales! partitions! talespaces! and inde"es#

$irtuall% no log is generated &or certain operations 'such as direct(path IN)*+T, i&the NOLOGGING clause is used# The NOLOGGING attriute is not speci-ed at the

IN)*+T statement le.el ut is instead speci-ed /hen using the 0LT*+ or C+*0T*

statement &or a tale! partition! inde"! or talespace#

When a tale or inde" has NOLOGGING set! neither parallel nor serial direct(path

IN)*+T operations generate undo or redo logs# 1rocesses running /ith the

NOLOGGING option set run &aster ecause no redo is generated# 2o/e.er! a&ter a

NOLOGGING operation against a tale! partition! or inde"! i& a media &ailure occurs

e&ore a ac3up is ta3en! then all tales! partitions! and inde"es that ha.e een

modi-ed might e corrupted#

Note:

Direct(path IN)*+T operations 'e"cept &or dictionar% updates, ne.er generate undo

logs# The NOLOGGING attriute does not a4ect undo! onl% redo# To e precise!

NOLOGGING allo/s the direct(path IN)*+T operation to generate a negligile

amount o& redo 'range(in.alidation redo! as opposed to &ull image redo,#

For ac3/ard compatiilit%! [5N]+*CO$*+06L* is still supported as an alternate

3e%/ord /ith the C+*0T* T06L* statement# This alternate 3e%/ord might not e

supported! ho/e.er! in &uture releases#

0t the talespace le.el! the logging clause speci-es the de&ault logging attriute &or

all tales! inde"es! and partitions created in the talespace# When an e"isting

talespace logging attriute is changed % the 0LT*+ T06L*)10C* statement! then

all tales! inde"es! and partitions created a&ter the 0LT*+ statement /ill ha.e the

ne/ logging attriute7 e"isting ones /ill not change their logging attriutes# The

talespace(le.el logging attriute can e o.erridden % the speci-cations at the

tale! inde"! or partition le.el#

 The de&ault logging attriute is LOGGING# 2o/e.er! i& %ou ha.e put the dataase in

NO0+C2I$*LOG mode! % issuing 0LT*+ D0T060)* NO0+C2I$*LOG! then alloperations that can e done /ithout logging /ill not generate logs! regardless o& the

speci-ed logging attriute#

Creating Inde"es in 1arallel

8ultiple processes can /or3 together simultaneousl% to create an inde"# 6% di.iding

the /or3 necessar% to create an inde" among multiple ser.er processes! Oracle can

create the inde" more uic3l% than i& a single ser.er process created the inde"

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seuentiall%#

1arallel inde" creation /or3s in much the same /a% as a tale scan /ith an O+D*+

6 clause# The tale is randoml% sampled and a set o& inde" 3e%s is &ound that

euall% di.ides the inde" into the same numer o& pieces as the DO1# 0 -rst set o&

uer% processes scans the tale! e"tracts 3e%(ro/id pairs! and sends each pair to aprocess in a second set o& uer% processes ased on 3e%# *ach process in the

second set sorts the 3e%s and uilds an inde" in the usual &ashion# 0&ter all inde"

pieces are uilt! the parallel coordinator simpl% concatenates the pieces '/hich are

ordered, to &orm the -nal inde"#

1arallel local inde" creation uses a single ser.er set# *ach ser.er process in the set

is assigned a tale partition to scan and &or /hich to uild an inde" partition#

6ecause hal& as man% ser.er processes are used &or a gi.en DO1! parallel local

inde" creation can e run /ith a higher DO1#

 ou can optionall% speci&% that no redo and undo logging should occur during inde"

creation# This can signi-cantl% impro.e per&ormance ut temporaril% renders the

inde" unreco.erale# +eco.erailit% is restored a&ter the ne/ inde" is ac3ed up# I&

%our application can tolerate a /indo/ /here reco.er% o& the inde" reuires it to e

re(created! then %ou should consider using the NOLOGGING clause#

 The 10+0LL*L clause in the C+*0T* IND*; statement is the onl% /a% in /hich %ou

can speci&% the DO1 &or creating the inde"# I& the DO1 is not speci-ed in the parallel

clause o& C+*0T* IND*;! then the numer o& C15s is used as the DO1# I& there is no

10+0LL*L clause! inde" creation is done seriall%#

Note:

When creating an inde" in parallel! the )TO+0G* clause re&ers to the storage o&

each o& the suinde"es created % the uer% ser.er processes# There&ore! an inde"

created /ith an INITI0L o& < 86 and a DO1 o& => consumes at least ?@ 86 o& storage

during inde" creation ecause each process starts /ith an e"tent o& < 86# When the

uer% coordinator process comines the sorted suinde"es! some o& the e"tents

might e trimmed! and the resulting inde" might e smaller than the reuested ?@

86#

When %ou add or enale a 5NIA5* or 1+I80+ B* constraint on a tale! %oucannot automaticall% create the reuired inde" in parallel# Instead! manuall% create

an inde" on the desired columns! using the C+*0T* IND*; statement and an

appropriate 10+0LL*L clause! and then add or enale the constraint# Oracle then

uses the e"isting inde" /hen enaling or adding the constraint#

8ultiple constraints on the same tale can e enaled concurrentl% and in parallel i& 

all the constraints are alread% in the *N06L* NO$0LID0T* state# In the &ollo/ing

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e"ample! the 0LT*+ T06L* ### *N06L* CON)T+0INT statement per&orms the tale

scan that chec3s the constraint in parallel:

C+*0T* T06L* a 'a= N586*+ CON)T+0INT ach C2*CB 'a= @, *N06L*

NO$0LID0T*,

10+0LL*L7IN)*+T INTO a .alues '=,7

CO88IT7

0LT*+ T06L* a *N06L* CON)T+0INT ach7