2023-04-11 monetdb-BAT及投影限制处理-分析

摘要:

monetdb-BAT及投影限制处理-分析

BAT说明

官方说明:

Design Overview | MonetDB Docs

@item @strong{BAT Alignment:}
Due to the mapping of multi-ary datamodels onto the BAT model, we
expect many correspondences among BATs, e.g.
@emph{bat(oid,attr1),..  bat(oid,attrN)} vertical
decompositions. Frequent activities will be to jump from one
attribute to the other (`bunhopping'). If the head columns are
equal lists in two BATs, merge or even array lookups can be used
instead of hash lookups. The alignment interface makes these
relations explicitly manageable.

数据结构定义:

typedef struct BAT {
	/* static bat pro