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From: jacktby jacktby <[email protected]>
To: [email protected]
Cc: [email protected]
Subject: Re: Index AmInsert Parameter Confused?
Date: Wed, 27 Sep 2023 11:03:40 +0800
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAEze2Wi2FO3ZZiMPPUYA8k7C=Rf9+Con3kK3h=yMPnZ_tv52JA@mail.gmail.com>
References: <[email protected]>
	<CAEze2Wi2FO3ZZiMPPUYA8k7C=Rf9+Con3kK3h=yMPnZ_tv52JA@mail.gmail.com>



> 2023年9月27日 00:45，Matthias van de Meent <[email protected]> 写道：
> 
> On Tue, 26 Sept 2023 at 18:38, jacktby jacktby <[email protected]> wrote:
>> 
>> typedef bool (*aminsert_function) (Relation indexRelation,
>>  Datum *values,
>>  bool *isnull,
>>  ItemPointer heap_tid,
>>  Relation heapRelation,
>>  IndexUniqueCheck checkUnique,
>>  bool indexUnchanged,
>>  struct IndexInfo *indexInfo);
>> 
>> Why is there a heap_tid, We haven’t inserted the value, so where does it from ?
> 
> Index insertion only happens after the TableAM tuple has been
> inserted. As indexes refer to locations in the heap, this TID contains
> the TID of the table tuple that contains the indexed values, so that
> the index knows which tuple to refer to.
> 
> Note that access/amapi.h describes only index AM APIs; it does not
> cover the table AM APIs descibed in access/tableam.h
> 
> Kind regards,
> 
> Matthias van de Meent
1.Thanks, so if we insert a tuple into a table which has a index on itself, pg will insert tuple into heap firstly, and the give the heaptid form heap to the Index am api right?
2. I’m trying to implement a new index, but I just need the data held in index table, I hope it’s not inserted into heap, because the all data I want can be in index table.

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