materialized-views

Materialized views with MySQL

由 北战南征 提交于 2019-12-11 09:12:22
问题 Emulated materialized views with MySQL has good performance? I'm learning how to do with this link thanks Correction: "Materialized views" to "Emulated materialized views". 回答1: MySQL doesn't have materialized views - the link just creates a table and stuffs data into it so the table can be indexed. That means the performance is par with a normal table, but you also have the overhead of flushing & repopulating the table (including indexes). I didn't see what engine the table was using, but

Not able to create Materialized query on AS400

由 前提是你 提交于 2019-12-11 08:55:35
问题 I get an error message when trying to create materialized query in as400 I use winSql for the connection. The syntax seems valid. Could you please point out what am I doing wrong? This is the statement I am trying to execute CREATE TABLE AAA.TEST_MQ AS ( SELECT test.* FROM AAA.TABLE_NAME test ) REFRESH DEFERRED This is the error message: Error: SQL0104 - Token <END-OF-STATEMENT> was not valid. Valid tokens: IMMEDIATE <IDENTIFIER>. (State:37000, Native Code: FFFFFF98) I Tried creating an

ORA-12015: cannot create a fast refresh materialized view from a complex query

由 萝らか妹 提交于 2019-12-11 04:32:22
问题 I am using below query to build a materialized view. CREATE MATERIALIZED VIEW gcms_business_profile_mview BUILD IMMEDIATE REFRESH FAST WITH PRIMARY KEY START WITH SYSDATE NEXT (TRUNC (SYSDATE + 1) + 20 / 96) AS SELECT DISTINCT obp.bp_id, obp.bp_typ_cd, os.spcl_desc, obpi.frs_nm, obpi.mdl_nm, NVL (rep_lst_nm.lst_nm, othr_lst_nm.lst_nm) last_name, NVL (rep_lst_nm.lst_nm_typ_id, othr_lst_nm.lst_nm_typ_id) last_name_type_id FROM tr_ods.ods_business_parties obp LEFT JOIN ( SELECT bp_id, speciality

Refreshing a materialized view does not include added column

由 我是研究僧i 提交于 2019-12-10 16:13:47
问题 From the manual CREATE MATERIALIZED VIEW is similar to CREATE TABLE AS, except that it also remembers the query used to initialize the view, so that it can be refreshed later upon demand. As I understand refreshing a materialized view should have the same effect as re create view as . But it is not what happens here. Create a table with a single column drop table if exists t cascade; create table t (a int); insert into t (a) values (1); Create the materialized view create materialized view

Subquery's rand() column re-evaluated for every repeated selection in MySQL 5.7/8.0 vs MySQL 5.6

由 [亡魂溺海] 提交于 2019-12-09 13:46:18
问题 I am doing a subquery in which I have a calculated column involving random number generation. In the base query I select this column twice. MySQL 5.6 works as I expect, the calculated value being called once and fixed. The 5.7+/8.0+ execution seems to re-evaluate the subquery's column value individually for each selection. Is this correct behavior? What can I do to force it work as expected in newer versions of MySQL? CREATE TABLE t ( `id` BIGINT(20) NOT NULL PRIMARY KEY AUTO_INCREMENT )

“Missing table” on materialized view

由 拥有回忆 提交于 2019-12-07 17:17:26
I have the following entity: @Entity @Table(name = "full_address") public class FullAddress { @Id @Column(name = "guid") private String id; @Column(name = "address") private String address; //getters and setters omitted } Also I create materialized view as follows: CREATE TABLE address_table ( -- address fields, aoid VARCHAR(36), CONSTRAINT address_pk PRIMARY KEY (aoid) ); CREATE MATERIALIZED VIEW full_address AS SELECT buildFullAddressById(addrobj.aoid) AS address, addrobj.aoid AS guid FROM address_table AS addrobj; -- buildFullAddressById is an sql function which is not important here When I

MySQL VIEW vs. embedded query, which one is faster?

由 青春壹個敷衍的年華 提交于 2019-12-07 15:42:55
问题 I'm going to optimize a MySQL embedded query with a view, but I'm not sure whether it will give an effect: SELECT id FROM (SELECT * FROM t); I want to convert it to: CREATE VIEW v AS SELECT * FROM t; SELECT id FROM v; I've heard about "indexed views" in SQL Server, but I'm not sure about MySQL. Any help would be appreciated. Thanks! 回答1: Indexed views in SQL Server are generally called "materialized views", which MySQL does not support. MySQL's VIEW support is rather limited in comparison to

oracle materialized view refresh time

由 拈花ヽ惹草 提交于 2019-12-06 02:22:17
问题 anyone able to tell me how often a materialized view is set to refresh with the following setting plz? REFRESH FORCE ON DEMAND START WITH sysdate+0 NEXT (round(sysdate) + 1/24) + 1 i think i read it as every hour but i'm not sure 回答1: SQL> alter session set nls_date_format = 'yyyy-mm-dd :hh24:mi:ss'; Session changed. SQL> select sysdate from dual; SYSDATE -------------------- 2008-12-19 :12:18:28 SQL> select (round(sysdate) + 1/24) + 1 from dual; (ROUND(SYSDATE)+1/24 -------------------- 2008

Oracle materialized view question

由 南楼画角 提交于 2019-12-05 16:26:51
I have a table that holds information about different events, for example CREATE TABLE events ( id int not null primary key, event_date date, ... ) I realized that 90% of all queries access only today events; the older rows are stored for history and eventually moved to an archive table. However, events table is still large, and I wonder if I can improve the performance by creating a materialized view that has something like WHERE event_date = trunc(sysdate) and maybe index on event_date ? Is it allowed at all? Thanks yes this is allowed see "primary key materialized view": Primary key

List grants and privileges for a materialized view in PostgreSQL

由 空扰寡人 提交于 2019-12-05 14:29:00
问题 I need to determine what privileges are currently granted for some materialized views in my database. The query to do this for a table or standard view is pretty straight forward: SELECT grantee, string_agg(privilege_type, ', ') AS privileges FROM information_schema.table_privileges WHERE table_schema = 'some_schema' AND table_name = 'some_table' GROUP by grantee; That said, there doesn't seem to be an analogous table for materialized views. Where does PostgreSQL store this information? 回答1:
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