com.pingcap.tikv.expression

类 PartitionPruner

java.lang.Object

com.pingcap.tikv.expression.PartitionPruner

public class PartitionPruner
extends Object

构造器概要

构造器

构造器和说明
PartitionPruner()

方法概要

限定符和类型	方法和说明
static List<Expression>	extractLogicalOrComparisonExpr(List<Expression> filters)
static void	generateRangeExprs(TiPartitionInfo partInfo, List<Expression> partExprs, TiParser parser, String partExprStr, int lessThanIdx) Convert the TiPartitionDef to ranges' expression.
static List<TiPartitionDef>	prune(TiTableInfo tableInfo, List<Expression> filters) When table is a partition table and its type is range.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

PartitionPruner

public PartitionPruner()

方法详细资料

extractLogicalOrComparisonExpr

public static List<Expression> extractLogicalOrComparisonExpr(List<Expression> filters)

prune

public static List<TiPartitionDef> prune(TiTableInfo tableInfo,
                                         List<Expression> filters)

When table is a partition table and its type is range. We use this method to do the pruning. Range partition has two types: 1. RANGE partitioning 2. RANGE COLUMNS partitioning https://dev.mysql.com/doc/mysql-partitioning-excerpt/5.7/en/partitioning-range.html https://dev.mysql.com/doc/mysql-partitioning-excerpt/5.7/en/partitioning-columns-range.html

参数:

filters - is where condition belong to a select statement.

返回:

a pruned partition for scanning.

generateRangeExprs

public static void generateRangeExprs(TiPartitionInfo partInfo,
                                      List<Expression> partExprs,
                                      TiParser parser,
                                      String partExprStr,
                                      int lessThanIdx)

Convert the TiPartitionDef to ranges' expression.
For example,
"partition by range(YEAR(birthday)) ("
+ s"partition p0 values less than (1995),"
+ s"partition p1 values less than (1997),"
+ s"partition p2 values less than MAXVALUE)")
will be converted to
[
[year(birthday@DATE) LESS_THAN 1995],
[[year(birthday@DATE) GREATER_EQUAL 1995] AND [year(birthday@DATE) LESS_THAN 1997]],
[[year(birthday@DATE) GREATER_EQUAL 1997] AND 1]
]