SUBSTRING_INDEX(from_id,'@',-1) CREATEORREPLACEFUNCTIONsubstring_index(varchar,varchar,integer)RETURNSvarcharAS$$DECLAREtokens varchar[];length integer;indexnum integer;BEGINtokens:=pg_catalog.string_to_array($1,$2);length:=pg_catalog.array_upper(tokens,1);indexnum:=length-($3*-1)+1;IF$3...
Greenplum支持B-tree、bitmap、函数索引等,这里介绍一下B-tree索引 create table test_index_1 as select * from test_distribute_1; select id,flag from test_index_1 where id = 100; 1. 2. 3. 接下来在flag字段上创建bitmap索引 create table test_index_2_idx on test_index_1 (id); 1. 再次...
(SELECT current_setting($$block_size$$)::numeric) AS bs, CASE WHEN SUBSTRING(SPLIT_PART(v, $$ $$, 2) FROM $$#"[0-9]+.[0-9]+#"%$$ for $$#$$) IN ($$8.0$$,$$8.1$$,$$8.2$$) THEN 27 ELSE 23 END AS hdr, CASE WHEN v ~ $$mingw32$$ OR v ~ $$64-bit$$ THEN ...
get_columns="select a.attname,pg_catalog.format_type(a.atttypid,a.atttypmod),\ (select substring(pg_catalog.pg_get_expr(d.adbin,d.adrelid) for 128) \ from pg_catalog.pg_attrdef d where d.adrelid=a.attrelid and d.adnum=a.attnum and a.atthasdef) \ as default,a.attnotnull ...
-- Name: idx_yyyymmdd; Type: INDEX; Schema: public; Owner: gpadmin; Tablespace: -- CREATE INDEX idx_yyyymmdd ON tb1_partition_range_yyyymmdd USING btree (yyyymmdd); -- -- Greenplum Database database dump complete -- 还有一种方法就是\d table_name查看。这个只能查看字段信息啥的。
(SELECTsubstring(pg_catalog.pg_get_expr(d.adbin,d.adrelid)for128)FROMpg_catalog.pg_attrdef dWHEREd.adrelid=a.attrelidANDd.adnum=a.attnumANDa.atthasdef),a.attnotnull,a.attnum,a.attstorage,pg_catalog.col_description(a.attrelid,a.attnum)FROMpg_catalog.pg_attribute aLEFTOUTERJOINpg_...
-- Name: idx_yyyymmdd; Type: INDEX; Schema: public; Owner: gpadmin; Tablespace:-- CREATE INDEX idx_yyyymmdd ON tb1_partition_range_yyyymmdd USING btree (yyyymmdd);-- -- Greenplum Database database dump complete -- 还有⼀种⽅法就是\d table_name查看。这个只能查看字段信息啥的。testdb=...
About Concurrency Control in Greenplum Database Example of Managing Transaction IDs About Parallel Data Loading About Redundancy and Failover in Greenplum Database About Database Statistics in Greenplum Database VMware Greenplum on vSphere Overview Architecture Planning VMware vSphere with Greenplum Green...
增加了对覆盖索引(covering index)的支持。覆盖索引允许用户使用INCLUDE 子句将额外的列添加到索引中,对于执行索引 (index-only)扫描非常有用,特别是对于那些不能被B-tree所索引的数据类型。 Greenplum 查询优化器部分支持索引扫描和覆盖索引。 Index-only scans can answer queries from an index alone without accessi...
•INDEX策略 一个表只建一个唯一索引 唯一索引全包含DK字段 •分析表 vacuumanalyzeusertable; vacuumfullsystemtable; PostgreSql语法特征 •PostgreSQL是一种关系型数据库管理系统 (RDBMS)。 •Greenplum基于PostgreSQL,但也不是 Postgres所有特性都能使用,比如: ...