TYPO3 Core

Checking a typical typo3 8.7 database, using the percona toolskit (https://www.percona.com/software/database-tools/percona-toolkit) command "pt-duplicate-key-checker", gives me the following result:

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2. typo3.index_words
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1. Key metaphone ends with a prefix of the clustered index
2. Key definitions:
3. KEY `metaphone` (`metaphone`,`wid`)
4. PRIMARY KEY (`wid`),
5. Column types:
6. `metaphone` int(11) not null default '0'
7. `wid` int(11) not null default '0'
8. To shorten this duplicate clustered index, execute:
   ALTER TABLE `typo3`.`index_words` DROP INDEX `metaphone`, ADD INDEX `metaphone` (`metaphone`);

1. Key baseword ends with a prefix of the clustered index
2. Key definitions:
3. KEY `baseword` (`baseword`,`wid`),
4. PRIMARY KEY (`wid`),
5. Column types:
6. `baseword` varchar(60) not null default ''
7. `wid` int(11) not null default '0'
8. To shorten this duplicate clustered index, execute:
   ALTER TABLE `typo3`.`index_words` DROP INDEX `baseword`, ADD INDEX `baseword` (`baseword`);

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2. typo3.sys_category
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1. parent is a left-prefix of category_list
2. Key definitions:
3. KEY `parent` (`pid`),
4. KEY `category_list` (`pid`,`deleted`,`sys_language_uid`)
5. Column types:
6. `pid` int(11) not null default '0'
7. `deleted` smallint(6) not null default '0'
8. `sys_language_uid` int(11) not null default '0'
9. To remove this duplicate index, execute:
   ALTER TABLE `typo3`.`sys_category` DROP INDEX `parent`;

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2. typo3.sys_domain
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1. parent is a left-prefix of getDomainStartPage
2. Key definitions:
3. KEY `parent` (`pid`),
4. KEY `getDomainStartPage` (`pid`,`hidden`,`domainName`)
5. Column types:
6. `pid` int(11) unsigned not null default '0'
7. `hidden` smallint(5) unsigned not null default '0'
8. `domainname` varchar(80) not null default ''
9. To remove this duplicate index, execute:
   ALTER TABLE `typo3`.`sys_domain` DROP INDEX `parent`;

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2. typo3.sys_log
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1. Key recuidIdx ends with a prefix of the clustered index
2. Key definitions:
3. KEY `recuidIdx` (`recuid`,`uid`),
4. PRIMARY KEY (`uid`),
5. Column types:
6. `recuid` int(11) unsigned not null default '0'
7. `uid` int(11) unsigned not null auto_increment
8. To shorten this duplicate clustered index, execute:
   ALTER TABLE `typo3`.`sys_log` DROP INDEX `recuidIdx`, ADD INDEX `recuidIdx` (`recuid`);

In order to save some disc space and make the world a little bit better, please remove this five duplicate database indexes.
All definition can be found in typo3/sysext/core/ext_tables.sql