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greenplum error!

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在本文中，我们将带你了解greenplumerror!在这篇文章中，同时我们还将给您一些技巧，以帮助您实现更有效的ConcurrencyControlinGreenplumDatabase、Deepg

在本文中，我们将带你了解greenplum error!在这篇文章中，同时我们还将给您一些技巧，以帮助您实现更有效的Concurrency Control in Greenplum Database、Deepgreen DB 是什么（含Deepgreen和Greenplum下载地址）、Deepgreen(Greenplum) DBA常用运维SQL、Deepgreen/Greenplum 删除节点步骤。

本文目录一览：

greenplum error!

greenplum error!

20160923:22:17:32:026503 gpinitsystem:host-192-168-111-19:gpadmin-[INFO]:-Checking Master host
20160923:22:17:32:026503 gpinitsystem:host-192-168-111-19:gpadmin-[WARN]:-Have lock file /tmp/.s.PGSQL.5432.lock but no process running on port 5432
20160923:22:17:32:gpinitsystem:host-192-168-111-19:gpadmin-[FATAL]:-Found indication of postmaster process on port 5432 on Master host Script Exiting!

移除 lock 文件 /tmp/.s.PGSQL.5432.lock

20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total segment instance count from metadata     = 4
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-----------------------------------------------------
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Primary Segment Status
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-----------------------------------------------------
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total primary segments                         = 4
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total primary segment valid (at master)        = 4
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total primary segment failures (at master)     = 0
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total number of postmaster.pid files missing   = 0
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total number of postmaster.pid files found     = 4
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total number of postmaster.pid PIDs missing    = 0
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total number of postmaster.pid PIDs found      = 4
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total number of /tmp lock files missing        = 0
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total number of /tmp lock files found          = 4
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total number postmaster processes missing      = 0
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Total number postmaster processes found        = 4
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-----------------------------------------------------
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Mirror Segment Status
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-----------------------------------------------------
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-   Mirrors not configured on this array
20160923:22:35:49:023838 gpstate:host-192-168-111-19:gpadmin-[INFO]:-----------------------------------------------------
[gpadmin@host-192-168-111-19 ~]$ ls

Concurrency Control in Greenplum Database

Concurrency Control in Greenplum Database

Unlike traditional database systems which use locks for concurrency control, Greenplum Database (as does PostgreSQL) maintains data consistency by using a multiversion model (Multiversion Concurrency Control, MVCC). This means that while querying a database, each transaction sees a snapshot of data which protects the transaction from viewing inconsistent data that could be caused by (other) concurrent updates on the same data rows. This provides transaction isolation for each database session.
MVCC, by eschewing explicit locking methodologies of traditional database systems, minimizes lock contention in order to allow for reasonable performance in multiuser environments. The main advantage to using the MVCC model of concurrency control rather than locking is that in MVCC locks acquired for querying (reading) data do not conflict with locks acquired for writing data, and so reading never blocks writing and writing never blocks reading.
Greenplum Database provides various lock modes to control concurrent access to data in tables. Most Greenplum Database SQL commands automatically acquire locks of appropriate modes to ensure that referenced tables are not dropped or modified in incompatible ways while the command executes. For applications that cannot adapt easily to MVCC behavior, the LOCK command can be used to acquire explicit locks. However, proper use of MVCC will generally provide better performance than locks.

Deepgreen DB 是什么（含Deepgreen和Greenplum下载地址）

Deepgreen DB 是什么（含Deepgreen和Greenplum下载地址）

Deepgreen官网下载地址：http://vitessedata.com/products/deepgreen-db/download/ 不需要注册

Greenplum官网下载地址：https://network.pivotal.io/products/pivotal-gpdb/#/releases/118806/file_groups/1022 需要注册

            Deepgreen DB 全称 Vitesse Deepgreen DB，它是一个可扩展的大规模并行（通常称为MPP）数据仓库解决方案，起源于开源数据仓库项目Greenplum DB（通常称为GP或GPDB）。所以已经熟悉了GP的朋友，可以无缝切换到Deepgreen。
它几乎拥有GP的所有功能，在保有GP所有优势的基础上，Deepgreen对原查询处理引擎进行了优化，新一代查询处理引擎扩展了：
  • 优越的连接和聚合算法
  • 新的溢出处理子系统
  • 基于JIT的查询优化、矢量扫描和数据路径优化
下面简单介绍一下Deepgreen的主要特性（主要与Greenplum对比）：
1. 100% GPDB
Deepgreen与Greenplum几乎100%一致，这里说几乎，是因为Deepgreen也剔除了一些Greenplum上的鸡肋功能，例如MapReduce支持，可以说保有的都是精华。从SQL语法、存储过程语法，到数据存储格式，再到像gpstart/gpfdist等组件，Deepgreen为想要从Greenplum迁移过来的用户将迁移影响降到最低。尤其是在下面这些方面：
  • 除了以quicklz方式压缩的数据需要修改外，其他数据无需重新装载
  • DML和DDL语句没有任何改变
  • UDF（用户定义函数）语法没有任何改变
  • 存储过程语法没有任何改变
  • JDBC／ODBC等连接和授权协议没有任何改变
  • 运行脚本没有任何改变（例如备份脚本）
那么Deepgreen和Greenplum的不同之处在哪呢？总结成一个词就是：快！快！快！（重要的事情说三遍）。因为大部分的OLAP工作都与CPU的性能有关，所以针对CPU优化后的Deepgreen在性能测试中，可以达到比原Greenplum快3～5倍的性能。
2.更快的Decimal类型
Deepgreen提供了两个更精确的Decimal类型：Decimal64和Decimal128，它们比Greenplum原有的Decimal类型（Numeric）更有效。因为它们更精确，相比于fload／double类型，更适合用在银行等对数据准确性要求高的业务场景。
安装： 
这两个数据类型需要在数据库初始化以后，通过命令加载到需要的数据库中：
dgadmin@flash:~$ source deepgreendb/greenplum_path.sh
dgadmin@flash:~$ cd $GPHOME/share/postgresql/contrib/
dgadmin@flash:~/deepgreendb/share/postgresql/contrib$ psql postgres -f pg_decimal.sql
测试一把： 
使用语句：select avg(x), sum(2*x) from table
数据量：100万
dgadmin@flash:~$ psql -d postgres
psql (8.2.15)
Type "help" for help.

postgres=# drop table if exists tt;
NOTICE:  table "tt" does not exist, skipping
DROP TABLE
postgres=# create table tt(
postgres(# ii bigint,
postgres(#  f64 double precision,
postgres(# d64 decimal64,
postgres(# d128 decimal128,
postgres(# n numeric(15, 3))
postgres-# distributed randomly;
CREATE TABLE
postgres=# insert into tt
postgres-# select i,
postgres-#     i + 0.123,
postgres-#     (i + 0.123)::decimal64,
postgres-#     (i + 0.123)::decimal128,
postgres-#     i + 0.123
postgres-# from generate_series(1, 1000000) i;
INSERT 0 1000000
postgres=# \timing on
Timing is on.
postgres=# select count(*) from tt;
  count
---------
 1000000
(1 row)

Time: 161.500 ms
postgres=# set vitesse.enable=1;
SET
Time: 1.695 ms
postgres=# select avg(f64),sum(2*f64) from tt;
       avg        |       sum
------------------+------------------
 500000.622996815 | 1000001245993.63
(1 row)

Time: 45.368 ms
postgres=# select avg(d64),sum(2*d64) from tt;
    avg     |        sum
------------+-------------------
 500000.623 | 1000001246000.000
(1 row)

Time: 135.693 ms
postgres=# select avg(d128),sum(2*d128) from tt;
    avg     |        sum
------------+-------------------
 500000.623 | 1000001246000.000
(1 row)

Time: 148.286 ms
postgres=# set vitesse.enable=1;
SET
Time: 11.691 ms
postgres=# select avg(n),sum(2*n) from tt;
         avg         |        sum
---------------------+-------------------
 500000.623000000000 | 1000001246000.000
(1 row)

Time: 154.189 ms
postgres=# set vitesse.enable=0;
SET
Time: 1.426 ms
postgres=# select avg(n),sum(2*n) from tt;
         avg         |        sum
---------------------+-------------------
 500000.623000000000 | 1000001246000.000
(1 row)

Time: 296.291 ms
结果列表： 
45ms - 64位float
136ms - decimal64
148ms - decimal128
154ms - deepgreen numeric
296ms - greenplum numeric
通过上面的测试，decimal64（136ms）类型比deepgreen numeric（154ms）类型快，比greenplum numeric快两倍，生产环境中快5倍以上。
3.支持JSON
Deepgreen支持JSON类型，但是并不完全支持。不支持的函数有：json_each,json_each_text,json_extract_path,json_extract_path_text, json_object_keys, json_populate_record, json_populate_recordset, json_array_elements, and json_agg.
安装：
执行下面命令扩展json支持： 
dgadmin@flash:~$ psql postgres -f $GPHOME/share/postgresql/contrib/json.sql
测试一把： 
dgadmin@flash:~$ psql postgres
psql (8.2.15)
Type "help" for help.

postgres=# select ''[1,2,3]''::json->2;
 ?column?
----------
 3
(1 row)

postgres=# create temp table mytab(i int, j json) distributed by (i);
CREATE TABLE
postgres=# insert into mytab values (1, null), (2, ''[2,3,4]''), (3, ''[3000,4000,5000]'');
INSERT 0 3
postgres=#
postgres=# insert into mytab values (1, null), (2, ''[2,3,4]''), (3, ''[3000,4000,5000]'');
INSERT 0 3
postgres=# select i, j->2 from mytab;
 i | ?column?
---+----------
 2 | 4
 2 | 4
 1 |
 3 | 5000
 1 |
 3 | 5000
(6 rows)
4.高效压缩算法
Deepgreen延续了Greenplum的zlib压缩算法用于存储压缩。除此之外，Deepgreen还提供两种对数据库负载更优的压缩格式：zstd和lz4.
如果客户在列存或者只追加堆表存储时要求更优的压缩比，请选择zstd压缩算法。相比于zlib，zstd有更好的压缩比，并且能更有效利用CPU。
如果客户有大量读取需求，那么可以选择lz4压缩算法，因为它有着惊人的解压速度。虽然在压缩比上lz4并没有zlib和zstd那么出众，但是为了满足高读取负载作出一些牺牲还是值得的。
有关于这两种压缩算法的具体内容，详见其主页：
  • zstd主页 http://facebook.github.io/zstd/
  • lz4主页 http://lz4.github.io/lz4/
测试一把：
这里只针对 不压缩／zlib／zstd／lz4四种，进行简单的测试，我的机器性能并不高，所有结果仅供参考： 
postgres=# create temp table ttnone (
postgres(#     i int,
postgres(#     t text,
postgres(#     default column encoding (compresstype=none))
postgres-# with (appendonly=true, orientation=column)
postgres-# distributed by (i);
CREATE TABLE
postgres=# \timing on
Timing is on.
postgres=# create temp table ttzlib(
postgres(#     i int,
postgres(#     t text,
postgres(#     default column encoding (compresstype=zlib, compresslevel=1))
postgres-# with (appendonly=true, orientation=column)
postgres-# distributed by (i);
CREATE TABLE
Time: 762.596 ms
postgres=# create temp table ttzstd (
postgres(#     i int,
postgres(#     t text,
postgres(#     default column encoding (compresstype=zstd, compresslevel=1))
postgres-# with (appendonly=true, orientation=column)
postgres-# distributed by (i);
CREATE TABLE
Time: 827.033 ms
postgres=# create temp table ttlz4 (
postgres(#     i int,
postgres(#     t text,
postgres(#     default column encoding (compresstype=lz4))
postgres-# with (appendonly=true, orientation=column)
postgres-# distributed by (i);
CREATE TABLE
Time: 845.728 ms
postgres=# insert into ttnone select i, ''user ''||i from generate_series(1, 100000000) i;
INSERT 0 100000000
Time: 104641.369 ms
postgres=# insert into ttzlib select i, ''user ''||i from generate_series(1, 100000000) i;
INSERT 0 100000000
Time: 99557.505 ms
postgres=# insert into ttzstd select i, ''user ''||i from generate_series(1, 100000000) i;
INSERT 0 100000000
Time: 98800.567 ms
postgres=# insert into ttlz4 select i, ''user ''||i from generate_series(1, 100000000) i;
INSERT 0 100000000
Time: 96886.107 ms
postgres=# select pg_size_pretty(pg_relation_size(''ttnone''));
 pg_size_pretty
----------------
 1708 MB
(1 row)

Time: 83.411 ms
postgres=# select pg_size_pretty(pg_relation_size(''ttzlib''));
 pg_size_pretty
----------------
 374 MB
(1 row)

Time: 4.641 ms
postgres=# select pg_size_pretty(pg_relation_size(''ttzstd''));
 pg_size_pretty
----------------
 325 MB
(1 row)

Time: 5.015 ms
postgres=# select pg_size_pretty(pg_relation_size(''ttlz4''));
 pg_size_pretty
----------------
 785 MB
(1 row)

Time: 4.483 ms
postgres=# select sum(length(t)) from ttnone;
    sum
------------
 1288888898
(1 row)

Time: 4414.965 ms
postgres=# select sum(length(t)) from ttzlib;
    sum
------------
 1288888898
(1 row)

Time: 4500.671 ms
postgres=# select sum(length(t)) from ttzstd;
    sum
------------
 1288888898
(1 row)

Time: 3849.648 ms
postgres=# select sum(length(t)) from ttlz4;
    sum
------------
 1288888898
(1 row)

Time: 3160.477 ms
5.数据采样
从Deepgreen 16.16版本开始，内建支持通过SQL进行数据真实采样，您可以通过定义行数或者定义采样比两种方式进行采样：
  • SELECT {select-clauses} LIMIT SAMPLE {n} ROWS;
  • SELECT {select-clauses} LIMIT SAMPLE {n} PERCENT;
测试一把： 
postgres=# select count(*) from ttlz4;
   count
-----------
 100000000
(1 row)

Time: 903.661 ms
postgres=# select * from ttlz4 limit sample 0.00001 percent;
    i     |       t
----------+---------------
  3442917 | user 3442917
  9182620 | user 9182620
  9665879 | user 9665879
 13791056 | user 13791056
 15669131 | user 15669131
 16234351 | user 16234351
 19592531 | user 19592531
 39097955 | user 39097955
 48822058 | user 48822058
 83021724 | user 83021724
  1342299 | user 1342299
 20309120 | user 20309120
 34448511 | user 34448511
 38060122 | user 38060122
 69084858 | user 69084858
 73307236 | user 73307236
 95421406 | user 95421406
(17 rows)

Time: 4208.847 ms
postgres=# select * from ttlz4 limit sample 10 rows;
    i     |       t
----------+---------------
 78259144 | user 78259144
 85551752 | user 85551752
 90848887 | user 90848887
 53923527 | user 53923527
 46524603 | user 46524603
 31635115 | user 31635115
 19030885 | user 19030885
 97877732 | user 97877732
 33238448 | user 33238448
 20916240 | user 20916240
(10 rows)

Time: 3578.031 ms
6.TPC-H性能
Deepgreen与Greenplum的性能对比，请参考我另外两个帖子：
《Deepgreen与Greenplum TPC-H性能测试对比（使用德哥脚本）》
《Deepgreen与Greenplum TPC-H性能测试对比（使用VitesseData脚本）》

Greenplum使用TPC-H测试过程及结果 ：

 https://blog.csdn.net/xfg0218/article/details/82785187

End~

原文链接

Deepgreen(Greenplum) DBA常用运维SQL

Deepgreen(Greenplum) DBA常用运维SQL

摘要： 1.查看对象大小(表、索引、数据库等) select pg_size_pretty(pg_relation_size(’$schema.$table’)); 示例： tpch=# select pg_size_pretty(pg_relation_size(''public.

1.查看对象大小(表、索引、数据库等)

 

select pg_size_pretty(pg_relation_size(’$schema.$table’));
示例：
tpch=# select pg_size_pretty(pg_relation_size(''public.customer''));
 pg_size_pretty
----------------
 122 MB
(1 row)

2.查看用户(非系统)表和索引

 

tpch=# select * from pg_stat_user_tables;
 relid | schemaname |       relname        | seq_scan | seq_tup_read | idx_scan | idx_tup_fetch | n_tup_ins | n_tup_upd | n_tup_del | last_vacuum | last_autovacuum | last_analyze
| last_autoanalyze
-------+------------+----------------------+----------+--------------+----------+---------------+-----------+-----------+-----------+-------------+-----------------+--------------
+------------------
 17327 | public     | partsupp             |        0 |            0 |        0 |             0 |         0 |         0 |         0 |             |                 |
|
 17294 | public     | customer             |        0 |            0 |        0 |             0 |         0 |         0 |         0 |             |                 |
|
 17158 | public     | part                 |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 17259 | public     | supplier             |        0 |            0 |        0 |             0 |         0 |         0 |         0 |             |                 |
|
 16633 | gp_toolkit | gp_disk_free         |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 17394 | public     | lineitem             |        0 |            0 |        0 |             0 |         0 |         0 |         0 |             |                 |
|
 17361 | public     | orders               |        0 |            0 |        0 |             0 |         0 |         0 |         0 |             |                 |
|
 16439 | gp_toolkit | __gp_masterid        |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 49164 | public     | number_xdrive        |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 17193 | public     | region               |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 49215 | public     | number_gpfdist       |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 16494 | gp_toolkit | __gp_log_master_ext  |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 40972 | public     | number               |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 16413 | gp_toolkit | __gp_localid         |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 16468 | gp_toolkit | __gp_log_segment_ext |        0 |            0 |          |               |         0 |         0 |         0 |             |                 |
|
 17226 | public     | nation               |        0 |            0 |        0 |             0 |         0 |         0 |         0 |             |                 |
|
(16 rows)

 

tpch=# select * from pg_stat_user_indexes;
 relid | indexrelid | schemaname | relname  |      indexrelname       | idx_scan | idx_tup_read | idx_tup_fetch
-------+------------+------------+----------+-------------------------+----------+--------------+---------------
 17259 |      17602 | public     | supplier | idx_supplier_nation_key |        0 |            0 |             0
 17327 |      17623 | public     | partsupp | idx_partsupp_partkey    |        0 |            0 |             0
 17327 |      17644 | public     | partsupp | idx_partsupp_suppkey    |        0 |            0 |             0
 17294 |      17663 | public     | customer | idx_customer_nationkey  |        0 |            0 |             0
 17361 |      17684 | public     | orders   | idx_orders_custkey      |        0 |            0 |             0
 17394 |      17705 | public     | lineitem | idx_lineitem_orderkey   |        0 |            0 |             0
 17394 |      17726 | public     | lineitem | idx_lineitem_part_supp  |        0 |            0 |             0
 17226 |      17745 | public     | nation   | idx_nation_regionkey    |        0 |            0 |             0
 17394 |      17766 | public     | lineitem | idx_lineitem_shipdate   |        0 |            0 |             0
 17361 |      17785 | public     | orders   | idx_orders_orderdate    |        0 |            0 |             0
(10 rows)

3.查看表分区

 

select b.nspname||''.''||a.relname as tablename, d.parname as partname from pg_class a, pg_namespace b, pg_partition c,pg_partition_rule d where a.relnamespace = b.oid and b.nspname = ''public'' and a.relname = ''customer'' and a.oid = c.parrelid and c.oid = d.paroid order by parname;
 tablename | partname
-----------+----------
(0 rows)

4.查看Distributed key

 

tpch=# select b.attname from pg_class a, pg_attribute b, pg_type c, gp_distribution_policy d, pg_namespace e where d.localoid = a.oid and a.relnamespace = e.oid and e.nspname = ''public'' and a.relname= ''customer'' and a.oid = b.attrelid and b.atttypid = c.oid and b.attnum > 0 and b.attnum = any(d.attrnums) order by attnum;
  attname
-----------
 c_custkey
(1 row)

5.查看当前存活的查询

 

select procpid as pid, sess_id as session, usename as user, current_query as query, waiting,date_trunc(''second'',query_start) as start_time, client_addr as useraddr from pg_stat_activity where datname =''$PGDATABADE''
and current_query not like ''%from pg_stat_activity%where datname =%'' order by start_time;

示例：
tpch=# select procpid as pid, sess_id as session, usename as user, current_query as query, waiting,date_trunc(''second'',query_start) as start_time, client_addr as useraddr from pg_stat_activity where datname =''tpch''
tpch-# and current_query not like ''%from pg_stat_activity%where datname =%'' order by start_time;
 pid | session | user | query | waiting | start_time | useraddr
-----+---------+------+-------+---------+------------+----------
(0 rows)

Deepgreen/Greenplum 删除节点步骤

Deepgreen/Greenplum 删除节点步骤

Deepgreen/Greenplum 删除节点步骤

Greenplum 和 Deepgreen 官方都没有给出删除节点的方法和建议，但实际上，我们可以对节点进行删除。由于不确定性，删除节点极有可能导致其他的问题，所以还行做好备份，谨慎而为。下面是具体的步骤：

1. 查看数据库当前状态（12 个实例）

[gpadmin@sdw1 ~]$ gpstate
20170816:12:53:25:097578 gpstate:sdw1:gpadmin-[INFO]:-Starting gpstate with args:
20170816:12:53:25:097578 gpstate:sdw1:gpadmin-[INFO]:-local Greenplum Version: ''postgres (Greenplum Database) 4.3.99.00 build Deepgreen DB''
20170816:12:53:25:097578 gpstate:sdw1:gpadmin-[INFO]:-master Greenplum Version: ''PostgreSQL 8.2.15 (Greenplum Database 4.3.99.00 build Deepgreen DB) on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC) 4.9.2 20150212 (Red Hat 4.9.2-6) compiled on Jul  6 2017 03:04:10''
20170816:12:53:25:097578 gpstate:sdw1:gpadmin-[INFO]:-Obtaining Segment details from master...
20170816:12:53:25:097578 gpstate:sdw1:gpadmin-[INFO]:-Gathering data from segments...
..
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-Greenplum instance status summary
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Master instance                                = Active
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Master standby                                 = No master standby configured
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total segment instance count from metadata     = 12
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Primary Segment Status
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total primary segments                         = 12
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total primary segment valid (at master)        = 12
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total primary segment failures (at master)     = 0
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total number of postmaster.pid files missing   = 0
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total number of postmaster.pid files found     = 12
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total number of postmaster.pid PIDs missing    = 0
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total number of postmaster.pid PIDs found      = 12
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total number of /tmp lock files missing        = 0
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total number of /tmp lock files found          = 12
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total number postmaster processes missing      = 0
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Total number postmaster processes found        = 12
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Mirror Segment Status
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-   Mirrors not configured on this array
20170816:12:53:27:097578 gpstate:sdw1:gpadmin-[INFO]:-----------------------------------------------------

2. 并行备份数据库

使用 gpcrondump 命令备份数据库，这里不赘述，不明白的可以翻看文档。

3. 关闭当前数据库

[gpadmin@sdw1 ~]$ gpstop -M fast
20170816:12:54:10:097793 gpstop:sdw1:gpadmin-[INFO]:-Starting gpstop with args: -M fast
20170816:12:54:10:097793 gpstop:sdw1:gpadmin-[INFO]:-Gathering information and validating the environment...
20170816:12:54:10:097793 gpstop:sdw1:gpadmin-[INFO]:-Obtaining Greenplum Master catalog information
20170816:12:54:10:097793 gpstop:sdw1:gpadmin-[INFO]:-Obtaining Segment details from master...
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-Greenplum Version: ''postgres (Greenplum Database) 4.3.99.00 build Deepgreen DB''
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:---------------------------------------------
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-Master instance parameters
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:---------------------------------------------
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   Master Greenplum instance process active PID   = 31250
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   Database                                       = template1
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   Master port                                    = 5432
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   Master directory                               = /hgdata/master/hgdwseg-1
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   Shutdown mode                                  = fast
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   Timeout                                        = 120
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   Shutdown Master standby host                   = Off
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:---------------------------------------------
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-Segment instances that will be shutdown:
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:---------------------------------------------
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   Host   Datadir                     Port    Status
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg0    25432   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg1    25433   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg2    25434   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg3    25435   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg4    25436   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg5    25437   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg6    25438   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg7    25439   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg8    25440   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg9    25441   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg10   25442   u
20170816:12:54:11:097793 gpstop:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg11   25443   u

Continue with Greenplum instance shutdown Yy|Nn (default=N):
> y
20170816:12:54:12:097793 gpstop:sdw1:gpadmin-[INFO]:-There are 0 connections to the database
20170816:12:54:12:097793 gpstop:sdw1:gpadmin-[INFO]:-Commencing Master instance shutdown with mode=''fast''
20170816:12:54:12:097793 gpstop:sdw1:gpadmin-[INFO]:-Master host=sdw1
20170816:12:54:12:097793 gpstop:sdw1:gpadmin-[INFO]:-Detected 0 connections to database
20170816:12:54:12:097793 gpstop:sdw1:gpadmin-[INFO]:-Using standard WAIT mode of 120 seconds
20170816:12:54:12:097793 gpstop:sdw1:gpadmin-[INFO]:-Commencing Master instance shutdown with mode=fast
20170816:12:54:12:097793 gpstop:sdw1:gpadmin-[INFO]:-Master segment instance directory=/hgdata/master/hgdwseg-1
20170816:12:54:13:097793 gpstop:sdw1:gpadmin-[INFO]:-Attempting forceful termination of any leftover master process
20170816:12:54:13:097793 gpstop:sdw1:gpadmin-[INFO]:-Terminating processes for segment /hgdata/master/hgdwseg-1
20170816:12:54:13:097793 gpstop:sdw1:gpadmin-[INFO]:-No standby master host configured
20170816:12:54:13:097793 gpstop:sdw1:gpadmin-[INFO]:-Commencing parallel segment instance shutdown, please wait...
20170816:12:54:13:097793 gpstop:sdw1:gpadmin-[INFO]:-0.00% of jobs completed
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-100.00% of jobs completed
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-   Segments stopped successfully      = 12
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-   Segments with errors during stop   = 0
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-Successfully shutdown 12 of 12 segment instances
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-Database successfully shutdown with no errors reported
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-Cleaning up leftover gpmmon process
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-No leftover gpmmon process found
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-Cleaning up leftover gpsmon processes
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-No leftover gpsmon processes on some hosts. not attempting forceful termination on these hosts
20170816:12:54:23:097793 gpstop:sdw1:gpadmin-[INFO]:-Cleaning up leftover shared memory

4. 以管理模式启动数据库

[gpadmin@sdw1 ~]$ gpstart -m
20170816:12:54:40:098061 gpstart:sdw1:gpadmin-[INFO]:-Starting gpstart with args: -m
20170816:12:54:40:098061 gpstart:sdw1:gpadmin-[INFO]:-Gathering information and validating the environment...
20170816:12:54:40:098061 gpstart:sdw1:gpadmin-[INFO]:-Greenplum Binary Version: ''postgres (Greenplum Database) 4.3.99.00 build Deepgreen DB''
20170816:12:54:40:098061 gpstart:sdw1:gpadmin-[INFO]:-Greenplum Catalog Version: ''201310150''
20170816:12:54:40:098061 gpstart:sdw1:gpadmin-[INFO]:-Master-only start requested in configuration without a standby master.

Continue with master-only startup Yy|Nn (default=N):
> y
20170816:12:54:41:098061 gpstart:sdw1:gpadmin-[INFO]:-Starting Master instance in admin mode
20170816:12:54:42:098061 gpstart:sdw1:gpadmin-[INFO]:-Obtaining Greenplum Master catalog information
20170816:12:54:42:098061 gpstart:sdw1:gpadmin-[INFO]:-Obtaining Segment details from master...
20170816:12:54:42:098061 gpstart:sdw1:gpadmin-[INFO]:-Setting new master era
20170816:12:54:42:098061 gpstart:sdw1:gpadmin-[INFO]:-Master Started...

5. 登陆管理数据库

[gpadmin@sdw1 ~]$ PGOPTIONS="-c gp_session_role=utility" psql -d postgres
psql (8.2.15)
Type "help" for help.

6. 删除 segment

postgres=# select * from gp_segment_configuration;
 dbid | content | role | preferred_role | mode | status | port  | hostname | address | replication_port | san_mounts
------+---------+------+----------------+------+--------+-------+----------+---------+------------------+------------
    1 |      -1 | p    | p              | s    | u      |  5432 | sdw1     | sdw1    |                  |
    2 |       0 | p    | p              | s    | u      | 25432 | sdw1     | sdw1    |                  |
    3 |       1 | p    | p              | s    | u      | 25433 | sdw1     | sdw1    |                  |
    4 |       2 | p    | p              | s    | u      | 25434 | sdw1     | sdw1    |                  |
    5 |       3 | p    | p              | s    | u      | 25435 | sdw1     | sdw1    |                  |
    6 |       4 | p    | p              | s    | u      | 25436 | sdw1     | sdw1    |                  |
    7 |       5 | p    | p              | s    | u      | 25437 | sdw1     | sdw1    |                  |
    8 |       6 | p    | p              | s    | u      | 25438 | sdw1     | sdw1    |                  |
    9 |       7 | p    | p              | s    | u      | 25439 | sdw1     | sdw1    |                  |
   10 |       8 | p    | p              | s    | u      | 25440 | sdw1     | sdw1    |                  |
   11 |       9 | p    | p              | s    | u      | 25441 | sdw1     | sdw1    |                  |
   12 |      10 | p    | p              | s    | u      | 25442 | sdw1     | sdw1    |                  |
   13 |      11 | p    | p              | s    | u      | 25443 | sdw1     | sdw1    |                  |
(13 rows)

postgres=# set allow_system_table_mods=''dml'';
SET

postgres=# delete from gp_segment_configuration where dbid=13;
DELETE 1

postgres=# select * from gp_segment_configuration;
 dbid | content | role | preferred_role | mode | status | port  | hostname | address | replication_port | san_mounts
------+---------+------+----------------+------+--------+-------+----------+---------+------------------+------------
    1 |      -1 | p    | p              | s    | u      |  5432 | sdw1     | sdw1    |                  |
    2 |       0 | p    | p              | s    | u      | 25432 | sdw1     | sdw1    |                  |
    3 |       1 | p    | p              | s    | u      | 25433 | sdw1     | sdw1    |                  |
    4 |       2 | p    | p              | s    | u      | 25434 | sdw1     | sdw1    |                  |
    5 |       3 | p    | p              | s    | u      | 25435 | sdw1     | sdw1    |                  |
    6 |       4 | p    | p              | s    | u      | 25436 | sdw1     | sdw1    |                  |
    7 |       5 | p    | p              | s    | u      | 25437 | sdw1     | sdw1    |                  |
    8 |       6 | p    | p              | s    | u      | 25438 | sdw1     | sdw1    |                  |
    9 |       7 | p    | p              | s    | u      | 25439 | sdw1     | sdw1    |                  |
   10 |       8 | p    | p              | s    | u      | 25440 | sdw1     | sdw1    |                  |
   11 |       9 | p    | p              | s    | u      | 25441 | sdw1     | sdw1    |                  |
   12 |      10 | p    | p              | s    | u      | 25442 | sdw1     | sdw1    |                  |
(12 rows)

7. 删除 filespace

postgres=# select * from pg_filespace_entry;
 fsefsoid | fsedbid |        fselocation
----------+---------+---------------------------
     3052 |       1 | /hgdata/master/hgdwseg-1
     3052 |       2 | /hgdata/primary/hgdwseg0
     3052 |       3 | /hgdata/primary/hgdwseg1
     3052 |       4 | /hgdata/primary/hgdwseg2
     3052 |       5 | /hgdata/primary/hgdwseg3
     3052 |       6 | /hgdata/primary/hgdwseg4
     3052 |       7 | /hgdata/primary/hgdwseg5
     3052 |       8 | /hgdata/primary/hgdwseg6
     3052 |       9 | /hgdata/primary/hgdwseg7
     3052 |      10 | /hgdata/primary/hgdwseg8
     3052 |      11 | /hgdata/primary/hgdwseg9
     3052 |      12 | /hgdata/primary/hgdwseg10
     3052 |      13 | /hgdata/primary/hgdwseg11
(13 rows)

postgres=#  delete from pg_filespace_entry where fsedbid=13;
DELETE 1

postgres=# select * from pg_filespace_entry;
 fsefsoid | fsedbid |        fselocation
----------+---------+---------------------------
     3052 |       1 | /hgdata/master/hgdwseg-1
     3052 |       2 | /hgdata/primary/hgdwseg0
     3052 |       3 | /hgdata/primary/hgdwseg1
     3052 |       4 | /hgdata/primary/hgdwseg2
     3052 |       5 | /hgdata/primary/hgdwseg3
     3052 |       6 | /hgdata/primary/hgdwseg4
     3052 |       7 | /hgdata/primary/hgdwseg5
     3052 |       8 | /hgdata/primary/hgdwseg6
     3052 |       9 | /hgdata/primary/hgdwseg7
     3052 |      10 | /hgdata/primary/hgdwseg8
     3052 |      11 | /hgdata/primary/hgdwseg9
     3052 |      12 | /hgdata/primary/hgdwseg10
(12 rows)

8. 退出管理模式，正常启动数据库

[gpadmin@sdw1 ~]$ gpstop -m
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Starting gpstop with args: -m
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Gathering information and validating the environment...
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Obtaining Greenplum Master catalog information
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Obtaining Segment details from master...
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Greenplum Version: ''postgres (Greenplum Database) 4.3.99.00 build Deepgreen DB''
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-There are 0 connections to the database
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Commencing Master instance shutdown with mode=''smart''
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Master host=sdw1
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Commencing Master instance shutdown with mode=smart
20170816:12:56:52:098095 gpstop:sdw1:gpadmin-[INFO]:-Master segment instance directory=/hgdata/master/hgdwseg-1
20170816:12:56:53:098095 gpstop:sdw1:gpadmin-[INFO]:-Attempting forceful termination of any leftover master process
20170816:12:56:53:098095 gpstop:sdw1:gpadmin-[INFO]:-Terminating processes for segment /hgdata/master/hgdwseg-1

[gpadmin@sdw1 ~]$ gpstart
20170816:12:57:02:098112 gpstart:sdw1:gpadmin-[INFO]:-Starting gpstart with args:
20170816:12:57:02:098112 gpstart:sdw1:gpadmin-[INFO]:-Gathering information and validating the environment...
20170816:12:57:02:098112 gpstart:sdw1:gpadmin-[INFO]:-Greenplum Binary Version: ''postgres (Greenplum Database) 4.3.99.00 build Deepgreen DB''
20170816:12:57:02:098112 gpstart:sdw1:gpadmin-[INFO]:-Greenplum Catalog Version: ''201310150''
20170816:12:57:02:098112 gpstart:sdw1:gpadmin-[INFO]:-Starting Master instance in admin mode
20170816:12:57:03:098112 gpstart:sdw1:gpadmin-[INFO]:-Obtaining Greenplum Master catalog information
20170816:12:57:03:098112 gpstart:sdw1:gpadmin-[INFO]:-Obtaining Segment details from master...
20170816:12:57:03:098112 gpstart:sdw1:gpadmin-[INFO]:-Setting new master era
20170816:12:57:03:098112 gpstart:sdw1:gpadmin-[INFO]:-Master Started...
20170816:12:57:03:098112 gpstart:sdw1:gpadmin-[INFO]:-Shutting down master
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:---------------------------
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-Master instance parameters
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:---------------------------
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-Database                 = template1
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-Master Port              = 5432
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-Master directory         = /hgdata/master/hgdwseg-1
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-Timeout                  = 600 seconds
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-Master standby           = Off
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:---------------------------------------
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-Segment instances that will be started
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:---------------------------------------
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   Host   Datadir                     Port
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg0    25432
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg1    25433
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg2    25434
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg3    25435
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg4    25436
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg5    25437
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg6    25438
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg7    25439
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg8    25440
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg9    25441
20170816:12:57:05:098112 gpstart:sdw1:gpadmin-[INFO]:-   sdw1   /hgdata/primary/hgdwseg10   25442

Continue with Greenplum instance startup Yy|Nn (default=N):
> y
20170816:12:57:07:098112 gpstart:sdw1:gpadmin-[INFO]:-Commencing parallel segment instance startup, please wait...
.......
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-Process results...
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-   Successful segment starts                                            = 11
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-   Failed segment starts                                                = 0
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-   Skipped segment starts (segments are marked down in configuration)   = 0
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-Successfully started 11 of 11 segment instances
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-----------------------------------------------------
20170816:12:57:14:098112 gpstart:sdw1:gpadmin-[INFO]:-Starting Master instance sdw1 directory /hgdata/master/hgdwseg-1
20170816:12:57:15:098112 gpstart:sdw1:gpadmin-[INFO]:-Command pg_ctl reports Master sdw1 instance active
20170816:12:57:15:098112 gpstart:sdw1:gpadmin-[INFO]:-No standby master configured.  skipping...
20170816:12:57:15:098112 gpstart:sdw1:gpadmin-[INFO]:-Database successfully started

9. 将删除节点的备份文件使用 psql 恢复到当前数据库

psql -d postgres -f xxxx.sql #这里不赘述恢复过程

备注：

1）本文使用的是只恢复删除节点的数据。

2）本文的过程，逆向执行，可以将删除的节点重新添加回来，但是数据恢复起来比较耗时，与重新建库恢复差不多。

 

转载自：https://www.sypopo.com/post/M95Rm39Or7/

关于greenplum error!的问题我们已经讲解完毕，感谢您的阅读，如果还想了解更多关于Concurrency Control in Greenplum Database、Deepgreen DB 是什么（含Deepgreen和Greenplum下载地址）、Deepgreen(Greenplum) DBA常用运维SQL、Deepgreen/Greenplum 删除节点步骤等相关内容，可以在本站寻找。

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