From: Zhangzhigang
Date: May 7 2012 8:53am
Subject: =?utf-8?B?5Zue5aSN77yaIFdoeSBpcyBjcmVhdGluZyBpbmRleGVzIGZhc3RlciBhZnRl?=
 =?utf-8?B?ciBpbnNlcnRpbmcgbWFzc2l2ZSBkYXRhIHJvd3M/?=
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johan ....=0A>Plain and simple: the indices get updated after every insert =
statement, =0Awhereas if you only create the index *after* the inserts, the=
 index gets created in a single operation, which is a lot more efficient..=
=0A=0A=0AOk, Creating the index *after* the inserts, the index gets created=
 in a single operation.=0ABut the indexes has to be updating row by row aft=
er the data rows has all been inserted. Does it work in this way?=0ASo i ca=
n not find the different overhead=C2=A0 about two ways.=0A=0A=0A=0A=0A=0A__=
______________________________=0A =E5=8F=91=E4=BB=B6=E4=BA=BA=EF=BC=9A Joha=
n De Meersman <vegivamp@stripped>=0A=E6=94=B6=E4=BB=B6=E4=BA=BA=EF=BC=9A Z=
hangzhigang <zzgang_2008@stripped> =0A=E6=8A=84=E9=80=81=EF=BC=9A mysql=
@lists.mysql.com =0A=E5=8F=91=E9=80=81=E6=97=A5=E6=9C=9F=EF=BC=9A 2012=E5=
=B9=B45=E6=9C=887=E6=97=A5, =E6=98=9F=E6=9C=9F=E4=B8=80, =E4=B8=8B=E5=8D=88=
 4:28=0A=E4=B8=BB=E9=A2=98: Re: Why is creating indexes faster after insert=
ing massive data rows?=0A =0A----- Original Message -----=0A> From: "Zhangz=
higang" <zzgang_2008@stripped>=0A> =0A> Creating indexes after insertin=
g massive data rows is faster than=0A> before inserting data rows.=0A> Plea=
se tell me why.=0A=0APlain and simple: the indices get updated after every =
insert statement, whereas if you only create the index *after* the inserts,=
 the index gets created in a single operation, which is a lot more efficien=
t.=0A=0AI seem to recall that inside of a transaction (thus, InnoDB or so) =
the difference is markedly less; I might be wrong, though.=0A=0A=0A-- =0ABi=
er met grenadyn=0AIs als mosterd by den wyn=0ASy die't drinkt, is eene kwez=
el=0AHy die't drinkt, is ras een ezel
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