select n.nspname AS “模式名”,c.relname AS “表名”,case when p.policytype=‘p’ then ‘分区表’ when p.policytype=‘r’ then ‘复制分布’ end “分布策略”, pg_get_table_distributedby(c.oid) “分布键” ,c.reloptions “压缩类型” from pg_class c left join gp_distribution_policy...
ALTER TABLE {table_name} EXCHANGE PARTITION {partition_name|FOR (RANK(number))|FOR (value)} WITH TABLE {cos_table_name} WITHOUT VALIDATION; 查询分区 与分区相关的系统表或者视图如下: pg_partition pg_partition_columns pg_partition_encoding pg_partition_rule pg_partition_templates pg_partitions 查看...
---查询正在执行的sql任务 SELECT procpid, start, now() - start AS lap, current_query FROM (SELECT backendid, pg_stat_get_backend_pid(S.backendid) AS procpid, pg_stat_get_backend_activity_start(S.backendid) AS start, pg_stat_get_backend_activity(S.backendid) AS current_...
greenplum 是一个 MPP 架构的数据库,由一个 master 和多个 segment 组成(还可选配置一个 standby master),其数据会根据设置的分布策略分布到在不同的 seg...
Greenplum中每个表都需要有一个分布键,如果你建表的时候没有显示使用语法DISTRIBUTED BY (column) 指定一个分布键,系统也会默认为你指定一个。分布目的是把数据打散到每个节点,打散的规则是hash或者randomly。这样在计算时可以充分利用每个节点的资源进行并行计算。
old name = attrnums The data type changed: from smallint[] to int2vector The new function pg_get_table_distributedby() was added to get the distribution policy for a table as a string. pg_class Field reloftype relallvisible relpersistence relispopulated relreplident relminmxid relrefs ...
Distributed by: (id) Partition by: (yyyymmdd) testdb=# 总体来说还是不太方便,下面创建一个自定义的函数进行查看: 1. 创建语言 CREATE PROCEDURAL LANGUAGE plpythonu; 2. 创建函数(代码如下): vim get_table_structure.sql create or replace function get_table_structure(tablename text) ...
Distributed by: (id) Partition by: (yyyymmdd) testdb=# 总体来说还是不太方便,下面创建一个自定义的函数进行查看: 1. 创建语言 CREATE PROCEDURAL LANGUAGE plpythonu; 2. 创建函数(代码如下): vim get_table_structure.sql create or replace function get_table_structure(tablename text) ...
在create table 和 alter table 的时候使用 DISTRIBUTED BY(HASH 分布)或 DISTRIBUTED RANDOMLY(随机分布)来决定数据如何分布。考虑要点: 均匀的数据分布:尽量确保每个 segment 实例存储了等量的数据;尽可能使用具有唯一性的 DK,比如主键、唯一键等。 本地操作与分布式操作:确保查询的处理(关联、排序、聚合等)尽可能在...
create temporary table tab_naotable(table_oid oid,table_name text,naotable text,cond char(1)) distributed by (table_oid); create or replace function f_get_aotable() returns void as $$ declare v_list_toid oid; v_list_tname text; ...