Skip to content
体验新版
项目
组织
正在加载...
登录
切换导航
打开侧边栏
Greenplum
Gpdb
提交
111f0e68
G
Gpdb
项目概览
Greenplum
/
Gpdb
通知
7
Star
1
Fork
0
代码
文件
提交
分支
Tags
贡献者
分支图
Diff
Issue
0
列表
看板
标记
里程碑
合并请求
0
DevOps
流水线
流水线任务
计划
Wiki
0
Wiki
分析
仓库
DevOps
项目成员
Pages
G
Gpdb
项目概览
项目概览
详情
发布
仓库
仓库
文件
提交
分支
标签
贡献者
分支图
比较
Issue
0
Issue
0
列表
看板
标记
里程碑
合并请求
0
合并请求
0
Pages
DevOps
DevOps
流水线
流水线任务
计划
分析
分析
仓库分析
DevOps
Wiki
0
Wiki
成员
成员
收起侧边栏
关闭侧边栏
动态
分支图
创建新Issue
流水线任务
提交
Issue看板
体验新版 GitCode,发现更多精彩内容 >>
提交
111f0e68
编写于
7月 29, 2019
作者:
M
Mel Kiyama
提交者:
David Yozie
7月 29, 2019
浏览文件
操作
浏览文件
下载
电子邮件补丁
差异文件
docs - clarified system columns not available for queries on replicated tables. (#8259)
上级
49de4c60
变更
4
隐藏空白更改
内联
并排
Showing
4 changed file
with
22 addition
and
9 deletion
+22
-9
gpdb-doc/dita/admin_guide/ddl/ddl-table.xml
gpdb-doc/dita/admin_guide/ddl/ddl-table.xml
+5
-0
gpdb-doc/dita/admin_guide/managing/monitor.xml
gpdb-doc/dita/admin_guide/managing/monitor.xml
+6
-6
gpdb-doc/dita/admin_guide/query/topics/functions-operators.xml
...doc/dita/admin_guide/query/topics/functions-operators.xml
+9
-2
gpdb-doc/dita/ref_guide/sql_commands/CREATE_TABLE.xml
gpdb-doc/dita/ref_guide/sql_commands/CREATE_TABLE.xml
+2
-1
未找到文件。
gpdb-doc/dita/admin_guide/ddl/ddl-table.xml
浏览文件 @
111f0e68
...
...
@@ -199,6 +199,11 @@
<li>
improve query performance by making it unnecessary to broadcast frequently used tables
to all segments.
</li>
</ul>
<note>
The hidden system columns (
<codeph>
ctid
</codeph>
,
<codeph>
cmin
</codeph>
,
<codeph>
cmax
</codeph>
,
<codeph>
xmin
</codeph>
,
<codeph>
xmax
</codeph>
, and
<codeph>
gp_segment_id
</codeph>
) cannot be referenced in user queries on replicated
tables because they have no single, unambiguous value. Greenplum Database returns a
<codeph>
column does not exist
</codeph>
error for the query.
</note>
</body>
<topic
id=
"topic35"
xml:lang=
"en"
>
<title>
Declaring Distribution Keys
</title>
...
...
gpdb-doc/dita/admin_guide/managing/monitor.xml
浏览文件 @
111f0e68
...
...
@@ -248,12 +248,12 @@ Distributed by: (sale_id)
</p>
<p>
A table is considered to have a balanced distribution if all segments have roughly the
same number of rows.
</p>
<note>
<p>
If you run this query on a replicated table it fails because Greenplum Database does
not permit user queries to reference the
<codeph>
gp_segment_id
</codeph>
system column in
replicated tables. Because every segment has all of the tables' rows, replicated tables
are evenly distributed by definition.
</p>
</note>
<note>
If you run this query on a replicated table, it fails because Greenplum Database does
not permit user queries to reference the system column
<codeph>
gp_segment_id
</codeph>
(or
the system columns
<codeph>
ctid
</codeph>
,
<codeph>
cmin
</codeph>
,
<codeph>
cmax
</codeph>
,
<codeph>
xmin
</codeph>
, and
<codeph>
xmax
</codeph>
) in replicated tables. Because every
segment has all of the tables' rows, replicated tables are evenly distributed by
definition.
</note>
</body>
</topic>
<topic
id=
"topic23"
xml:lang=
"en"
>
...
...
gpdb-doc/dita/admin_guide/query/topics/functions-operators.xml
浏览文件 @
111f0e68
...
...
@@ -147,8 +147,15 @@
such as
<codeph>
setval()
</codeph>
are not allowed to execute on distributed data in
Greenplum Database because they can cause inconsistent data between segment
instances.
</p>
<p>
A function can execute read-only queries on replicated tables (
<codeph>
DISTRIBUTED REPLICATED
</codeph>
)
on the segments, but any SQL command that modifies data must execute on the master instance.
</p>
<p>
A function can execute read-only queries on replicated tables (
<codeph>
DISTRIBUTED
REPLICATED
</codeph>
) on the segments, but any SQL command that modifies data
must execute on the master instance.
<note>
The hidden system columns (
<codeph>
ctid
</codeph>
,
<codeph>
cmin
</codeph>
,
<codeph>
cmax
</codeph>
,
<codeph>
xmin
</codeph>
,
<codeph>
xmax
</codeph>
, and
<codeph>
gp_segment_id
</codeph>
) cannot be referenced in user queries on
replicated tables because they have no single, unambiguous value. Greenplum
Database returns a
<codeph>
column does not exist
</codeph>
error for the
query.
</note></p>
<p>
To ensure data consistency, you can safely use
<codeph>
VOLATILE
</codeph>
and
<codeph>
STABLE
</codeph>
functions in statements that are evaluated on and run
from the master. For example, the following statements run on the master (statements
...
...
gpdb-doc/dita/ref_guide/sql_commands/CREATE_TABLE.xml
浏览文件 @
111f0e68
...
...
@@ -186,7 +186,8 @@ CREATE [ [GLOBAL | LOCAL] {TEMPORARY | TEMP} | UNLOGGED ] TABLE [IF NOT EXISTS]
be inherited by another table. The hidden system columns (
<codeph>
ctid
</codeph>
,
<codeph>
cmin
</codeph>
,
<codeph>
cmax
</codeph>
,
<codeph>
xmin
</codeph>
,
<codeph>
xmax
</codeph>
, and
<codeph>
gp_segment_id
</codeph>
) cannot be referenced in user
queries on replicated tables because they have no single, unambiguous value.
</p>
queries on replicated tables because they have no single, unambiguous value. Greenplum
Database returns a
<codeph>
column does not exist
</codeph>
error for the query.
</p>
<p>
The
<codeph>
PARTITION BY
</codeph>
clause allows you to divide the table into multiple
sub-tables (or parts) that, taken together, make up the parent table and share its schema.
Though the sub-tables exist as independent tables, the Greenplum Database restricts their
...
...
编辑
预览
Markdown
is supported
0%
请重试
或
添加新附件
.
添加附件
取消
You are about to add
0
people
to the discussion. Proceed with caution.
先完成此消息的编辑!
取消
想要评论请
注册
或
登录