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Update gin.h

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bjyb 2023-09-17 05:39:41 +08:00
parent 541ddd61a6
commit 81f221828d
1 changed files with 11 additions and 0 deletions
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src/include/access/gin.h
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@ -7,6 +7,17 @@
* src/include/access/gin.h
* --------------------------------------------------------------------------
*/
/*
GIN(Generalized Inverted Index) is an index structure that stores a set of key, posting list),
where the key is a key value and the posting list is a group of locations where the keys have
appeared. For example, in ('‘hello', '14:2 23:4 2 23:4'), it means that hello has appeared in the
ancestors of 14:2 and 23: 4. In PG, these positions are actually the tid (line number, including
data block ID(32bit) and item point(16 bit)) of tuples.
For each attribute in the table, it may be parsed into multiple key values when establishing
the corresponding gin index, so the tid of the same tuple may appear in the posting list of multiple keys.
*/
#ifndef GIN_H
#define GIN_H