implicit index created, do I need to also create an explicit index?

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От Mark Harrison
Тема implicit index created, do I need to also create an explicit index?
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Msg-id 437E49F3.1060702@pixar.com
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Ответы Re: implicit index created, do I need to also create an explicit index?  (Martijn van Oosterhout <kleptog@svana.org>)
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So I create a table with unique fields, and it creates an implicit index.

1.  This is a general purpose index, correct?  I.e. not used solely for
     ensuring uniqueness, so I don't need to create another index on
     the same field explicitly, right?

2.  What are the implications of creating another index, such as
      create index foo on tv_workspace(name)?  Is is just a duplicate
     of the implicitly created index?


create table tv_workspace (
     name varchar(32) unique not null,
     p4client varchar(64) unique not null,
     owner bigint not null
);
NOTICE:  CREATE TABLE / UNIQUE will create implicit index "tv_workspace_name_key" for table "tv_workspace"
NOTICE:  CREATE TABLE / UNIQUE will create implicit index "tv_workspace_p4client_key" for table "tv_workspace"


TIA!
Mark

--
Mark Harrison
Pixar Animation Studios

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