Re: [Maria-developers] How to get all fields in a given index?
Thanks a lot! Rongrong Rongrong On Tue, Sep 9, 2014 at 8:18 AM, Sergey Petrunia ser...@mariadb.com wrote: On Mon, Sep 08, 2014 at 08:54:00PM +0100, Rongrong wrote: I'm trying to implement some feature that requires to get the list of fields for a given index. I'm trying to follow the optimizer code to find some clue but am not successful so far. Can anyone give me some pointers? A TABLE object has a member called key_info. It is an array of structures describing each index. For an index $I, table-key_info[$I].usable_key_parts gives the number of key parts that the optimizer considers (it varies depending on extended_keys=on|off setting), Then, table-key_info[$I].key_part is an array of structures describing key parts. The most interesting are table-key_info[$I].key_part[$PART].field (the field itself) and table-key_info[$I].key_part[$PART].fieldnr (field number). Alternatively, there is table-field[$FIELD_NO].part_of_key - this is a bitmap which tells which indexes this field is a part of. BR Sergei -- Sergei Petrunia, Software Developer MariaDB | Skype: sergefp | Blog: http://s.petrunia.net/blog ___ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
Re: [Maria-developers] How to get all fields in a given index?
On Mon, Sep 08, 2014 at 08:54:00PM +0100, Rongrong wrote: I'm trying to implement some feature that requires to get the list of fields for a given index. I'm trying to follow the optimizer code to find some clue but am not successful so far. Can anyone give me some pointers? A TABLE object has a member called key_info. It is an array of structures describing each index. For an index $I, table-key_info[$I].usable_key_parts gives the number of key parts that the optimizer considers (it varies depending on extended_keys=on|off setting), Then, table-key_info[$I].key_part is an array of structures describing key parts. The most interesting are table-key_info[$I].key_part[$PART].field (the field itself) and table-key_info[$I].key_part[$PART].fieldnr (field number). Alternatively, there is table-field[$FIELD_NO].part_of_key - this is a bitmap which tells which indexes this field is a part of. BR Sergei -- Sergei Petrunia, Software Developer MariaDB | Skype: sergefp | Blog: http://s.petrunia.net/blog ___ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
[Maria-developers] How to get all fields in a given index?
Hi, I'm trying to implement some feature that requires to get the list of fields for a given index. I'm trying to follow the optimizer code to find some clue but am not successful so far. Can anyone give me some pointers? Thanks! Rongrong ___ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
