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Slony 是 PostgreSQL 领域中最广泛的复制解决方案之一。它不仅是最古老的复制实现之一，它也是一个拥有最广泛的外部工具支持的工具，比如 pgAdmin3。多年来，Slony 是在 PostgreSQL 中复制数据的惟一可行的解决方案。Slony 使用逻辑复制；Slony- I 一般要求表有主键, 或者唯一键；Slony 的工作不是基于 PostgreSQL 事务日志的；而是基于触发器的；基于逻辑复制高可用性；PostgreSQL 除了 slony；还有 Londiste,BDR 等等后续文章会讲到
1. 安装 Slony
下载地址：http://www.slony.info；安装步骤:
# tar -jxvf slony1-2.2.5.tar.bz2
# cd slony1-2.2.5
# ./configure –with-pgconfigdir=/opt/pgsql96/bin
# make
# make install
安装完成！
执行./configure 时；会在当前目录是否可以找到 pg_config 命令；本例 pg_config 在 /opt/pgsql96/bin 目录下；
2. Slony 架构图
3. 复制表
现有实验环境：
| 主机名 | IP | 角色 |
| PostgreSQL201 | 192.168.1.201 | master |
| PostgreSQL202 | 192.168.1.202 | slave |
3.1 在两台数据库中都创建一个 slony 的超级用户；专为 slony 服务
create user slony superuser password ‘li0924’;
3.2 本实验两台主机都有 lottu 数据库；以 lottu 数据库中的表作为实验对象；在两个数据库中以相同的方式创建该表 synctab，因为表结构不会自动复制。
create table synctab(id int primary key,name text);
3.3 在所有节点设置允许 Slony- I 用户远程登录；在 pg_hba.conf 文件添加
host all slony 192.168.1.0/24 trust
3.4 设置 slony(在 master 主机操作)
编写一个 slonik 脚本用于注册这些节点的脚本如下所示：
[postgres@Postgres201 ~]$ cat slony_setup.sh
#!/bin/sh
MASTERDB=lottu
SLAVEDB=lottu
HOST1=192.168.1.201
HOST2=192.168.1.202
DBUSER=slony
slonik<<_EOF_
cluster name = first_cluster;
# define nodes (this is needed by pretty much
# all slonik scripts)
node 1 admin conninfo = ‘dbname=$MASTERDB host=$HOST1 user=$DBUSER’;
node 2 admin conninfo = ‘dbname=$SLAVEDB host=$HOST2 user=$DBUSER’;
# init cluster
init cluster (id=1, comment = ‘Master Node’);
# group tables into sets
create set (id=1, origin=1, comment=’Our tables’);
set add table (set id=1, origin=1, id=1, fully qualified name = ‘lottu.synctab’, comment=’sample table’);
store node (id=2, comment = ‘Slave node’, event node=1);
store path (server = 1, client = 2, conninfo=’dbname=$MASTERDB host=$HOST1 user=$DBUSER’);
store path (server = 2, client = 1, conninfo=’dbname=$SLAVEDB host=$HOST2 user=$DBUSER’);
_EOF_
现在这个表在 Slony 的控制下，我们可以开始订阅脚本如下所示：
[postgres@Postgres201 ~]$ cat slony_subscribe.sh
#!/bin/sh
MASTERDB=lottu
SLAVEDB=lottu
HOST1=192.168.1.201
HOST2=192.168.1.202
DBUSER=slony
slonik<<_EOF_
cluster name = first_cluster;
node 1 admin conninfo = ‘dbname=$MASTERDB host=$HOST1 user=$DBUSER’;
node 2 admin conninfo = ‘dbname=$SLAVEDB host=$HOST2 user=$DBUSER’;
subscribe set (id = 1, provider = 1, receiver = 2, forward = no);
_EOF_
在 master 主机执行脚本
[postgres@Postgres201 ~]$ ./slony_setup.sh
[postgres@Postgres201 ~]$ ./slony_subscribe.sh &
[1] 1225
定义了我们想要复制的东西之后，我们可以在每台主机启动 slon 守护进程
slon first_cluster ‘host=192.168.1.201 dbname=lottu user=slony’ &
slon first_cluster ‘host=192.168.1.202 dbname=lottu user=slony’ &
3.5 验证 slony- I 是否配置成功？
在 master 主机执行 dml 操作
[postgres@Postgres201 ~]$ psql lottu lottu
psql (9.6.0)
Type “help” for help.
lottu=# \d synctab
Table “lottu.synctab”
Column | Type | Modifiers
——–+———+———–
id | integer | not null
name | text |
Indexes:
“synctab_pkey” PRIMARY KEY, btree (id)
Triggers:
_first_cluster_logtrigger AFTER INSERT OR DELETE OR UPDATE ON synctab FOR EACH ROW EXECUTE PROCEDURE _first_cluster.logtrigger(‘_first_cluster’, ‘1’, ‘k’)
_first_cluster_truncatetrigger BEFORE TRUNCATE ON synctab FOR EACH STATEMENT EXECUTE PROCEDURE _first_cluster.log_truncate(‘1’)
Disabled user triggers:
_first_cluster_denyaccess BEFORE INSERT OR DELETE OR UPDATE ON synctab FOR EACH ROW EXECUTE PROCEDURE _first_cluster.denyaccess(‘_first_cluster’)
_first_cluster_truncatedeny BEFORE TRUNCATE ON synctab FOR EACH STATEMENT EXECUTE PROCEDURE _first_cluster.deny_truncate()
lottu=# insert into synctab values (1001,’lottu’);
INSERT 0 1
在 slave 主机查看是否对应变化
[postgres@Postgres202 ~]$ psql
psql (9.6.0)
Type “help” for help.
postgres=# \c lottu lottu
You are now connected to database “lottu” as user “lottu”.
lottu=> select * from synctab ;
id | name
——+——-
1001 | lottu
(1 row)
4. Slony- I 相关表或者视图查看
4.1 配置成功；会在所在的数据库中生成一个 schema
[postgres@Postgres201 ~]$ psql lottu lottu
psql (9.6.0)
Type “help” for help.
lottu=# \dn
List of schemas
Name | Owner
—————-+———-
_first_cluster | slony
lottu | lottu
public | postgres
(3 rows)
4.2 查看集群中的节点信息
lottu=# select * from _first_cluster.sl_node;
no_id | no_active | no_comment | no_failed
——-+———–+————-+———–
1 | t | Master Node | f
2 | t | Slave node | f
(2 rows)
4.3 查看集群中的集合信息
lottu=# select * from _first_cluster.sl_set;
set_id | set_origin | set_locked | set_comment
——–+————+————+————-
1 | 1 | | Our tables
(1 row)
4.4 查看集群中的表信息
lottu=# select * from _first_cluster.sl_table;
-[RECORD 1]————-
tab_id | 1
tab_reloid | 57420
tab_relname | synctab
tab_nspname | lottu
tab_set | 1
tab_idxname | synctab_pkey
tab_altered | f
tab_comment | sample table
5. 日常维护
5.1 Slony- I 向现有集群中增加一个复制表
以表 synctab2 为例：
create table synctab2(id int primary key,name text,reg_time timestamp);
我们要创建一个新的表格集; 脚本是这样的
[postgres@Postgres201 ~]$ cat slony_add_table_set.sh
#!/bin/sh
MASTERDB=lottu
SLAVEDB=lottu
HOST1=192.168.1.201
HOST2=192.168.1.202
DBUSER=slony
slonik<<_EOF_
cluster name = first_cluster;
node 1 admin conninfo = ‘dbname=$MASTERDB host=$HOST1 user=$DBUSER’;
node 2 admin conninfo = ‘dbname=$SLAVEDB host=$HOST2 user=$DBUSER’;
create set (id=2, origin=1, comment=’a second replication set’);
set add table (set id=2, origin=1, id=2, fully qualified name =’lottu.synctab2′, comment=’second table’);
subscribe set(id=1, provider=1,receiver=2);
subscribe set(id=2, provider=1,receiver=2);
merge set(id=1, add id=2,origin=1);
_EOF_
执行 slony_add_table_set.sh 脚本
[postgres@Postgres201 ~]$ ./slony_add_table_set.sh
<stdin>:8 subscription in progress before mergeSet. waiting
<stdin>:8 subscription in progress before mergeSet. waiting
查看是否添加成功
lottu=# select * from _first_cluster.sl_table;
-[RECORD 1]————–
tab_id | 1
tab_reloid | 57420
tab_relname | synctab
tab_nspname | lottu
tab_set | 1
tab_idxname | synctab_pkey
tab_altered | f
tab_comment | sample table
-[RECORD 2]————–
tab_id | 2
tab_reloid | 57840
tab_relname | synctab2
tab_nspname | lottu
tab_set | 1
tab_idxname | synctab2_pkey
tab_altered | f
tab_comment | second table
5.2 Slony- I 向现有集群中删除一个复制表
[postgres@Postgres201 ~]$ cat slony_drop_table.sh
#!/bin/sh
MASTERDB=lottu
SLAVEDB=lottu
HOST1=192.168.1.201
HOST2=192.168.1.202
DBUSER=slony
slonik<<_EOF_
cluster name = first_cluster;
node 1 admin conninfo = ‘dbname=$MASTERDB host=$HOST1 user=$DBUSER’;
node 2 admin conninfo = ‘dbname=$SLAVEDB host=$HOST2 user=$DBUSER’;
set drop table (id=2, origin=1);
_EOF_
执行 slony_drop_table.sh 脚本
[postgres@Postgres201 ~]$ ./slony_drop_table.sh
查看是否删除成功
lottu=# select * from _first_cluster.sl_table;
tab_id | tab_reloid | tab_relname | tab_nspname | tab_set | tab_idxname | tab_altered | tab_comment
——–+————+————-+————-+———+————–+————-+————–
1 | 57420 | synctab | lottu | 1 | synctab_pkey | f | sample table
(1 row)
5. 3 删除 slony
[postgres@Postgres201 ~]$ cat slony_drop_node.sh
#!/bin/sh
MASTERDB=lottu
SLAVEDB=lottu
HOST1=192.168.1.201
HOST2=192.168.1.202
DBUSER=slony
slonik<<_EOF_
cluster name = first_cluster;
node 1 admin conninfo = ‘dbname=$MASTERDB host=$HOST1 user=$DBUSER’;
node 2 admin conninfo = ‘dbname=$SLAVEDB host=$HOST2 user=$DBUSER’;
uninstall node (id = 1);
uninstall node (id = 2);
_EOF_
执行脚本如下：
[postgres@Postgres201 ~]$ ./slony_drop_node.sh
<stdin>:4: NOTICE: Slony-I: Please drop schema “_first_cluster”
<stdin>:4: NOTICE: drop cascades to 175 other objects
DETAIL: drop cascades to table _first_cluster.sl_node
drop cascades to table _first_cluster.sl_nodelock
drop cascades to table _first_cluster.sl_set
drop cascades to table _first_cluster.sl_setsync
drop cascades to table _first_cluster.sl_table
drop cascades to table _first_cluster.sl_sequence
drop cascades to table _first_cluster.sl_path
drop cascades to table _first_cluster.sl_listen
drop cascades to table _first_cluster.sl_subscribe
drop cascades to table _first_cluster.sl_event
drop cascades to table _first_cluster.sl_confirm
drop cascades to table _first_cluster.sl_seqlog
drop cascades to function _first_cluster.sequencelastvalue(text)
drop cascades to table _first_cluster.sl_log_1
drop cascades to table _first_cluster.sl_log_2
drop cascades to table _first_cluster.sl_log_script
drop cascades to table _first_cluster.sl_registry
drop cascades to table _first_cluster.sl_apply_stats
drop cascades to view _first_cluster.sl_seqlastvalue
drop cascades to view _first_cluster.sl_failover_targets
drop cascades to sequence _first_cluster.sl_local_node_id
drop cascades to sequence _first_cluster.sl_event_seq
drop cascades to sequence _first_cluster.sl_action_seq
drop cascades to sequence _first_cluster.sl_log_status
drop cascades to table _first_cluster.sl_config_lock
drop cascades to table _first_cluster.sl_event_lock
drop cascades to table _first_cluster.sl_archive_counter
drop cascades to table _first_cluster.sl_components
drop cascades to type _first_cluster.vactables
drop cascades to function _first_cluster.createevent(name,text)
drop cascades to function _first_cluster.createevent(name,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text,text,text,text,text)
drop cascades to function _first_cluster.denyaccess()
drop cascades to trigger _first_cluster_denyaccess on table lottu.synctab
drop cascades to function _first_cluster.lockedset()
drop cascades to function _first_cluster.getlocalnodeid(name)
drop cascades to function _first_cluster.getmoduleversion()
drop cascades to function _first_cluster.resetsession()
drop cascades to function _first_cluster.logapply()
drop cascades to function _first_cluster.logapplysetcachesize(integer)
drop cascades to function _first_cluster.logapplysavestats(name,integer,interval)
drop cascades to function _first_cluster.checkmoduleversion()
drop cascades to function _first_cluster.decode_tgargs(bytea)
drop cascades to function _first_cluster.logtrigger()
drop cascades to trigger _first_cluster_logtrigger on table lottu.synctab
drop cascades to function _first_cluster.terminatenodeconnections(integer)
drop cascades to function _first_cluster.killbackend(integer,text)
drop cascades to function _first_cluster.seqtrack(integer,bigint)
drop cascades to function _first_cluster.slon_quote_brute(text)
drop cascades to function _first_cluster.slon_quote_input(text)
drop cascades to function _first_cluster.slonyversionmajor()
drop cascades to function _first_cluster.slonyversionminor()
drop cascades to function _first_cluster.slonyversionpatchlevel()
drop cascades to function _first_cluster.slonyversion()
drop cascades to function _first_cluster.registry_set_int4(text,integer)
drop cascades to function _first_cluster.registry_get_int4(text,integer)
drop cascades to function _first_cluster.registry_set_text(text,text)
drop cascades to function _first_cluster.registry_get_text(text,text)
drop cascades to function _first_cluster.registry_set_timestamp(text,timestamp with time zone)
drop cascades to function _first_cluster.registry_get_timestamp(text,timestamp with time zone)
drop cascades to function _first_cluster.cleanupnodelock()
drop cascades to function _first_cluster.registernodeconnection(integer)
drop cascades to function _first_cluster.initializelocalnode(integer,text)
drop cascades to function _first_cluster.storenode(integer,text)
drop cascades to function _first_cluster.storenode_int(integer,text)
drop cascades to function _first_cluster.enablenode(integer)
drop cascades to function _first_cluster.enablenode_int(integer)
drop cascades to function _first_cluster.disablenode(integer)
drop cascades to function _first_cluster.disablenode_int(integer)
drop cascades to function _first_cluster.dropnode(integer[])
drop cascades to function _first_cluster.dropnode_int(integer)
drop cascades to function _first_cluster.prefailover(integer,boolean)
drop cascades to function _first_cluster.failednode(integer,integer,integer[])
drop cascades to function _first_cluster.failednode2(integer,integer,bigint,integer[])
drop cascades to function _first_cluster.failednode3(integer,integer,bigint)
drop cascades to function _first_cluster.failoverset_int(integer,integer,bigint)
drop cascades to function _first_cluster.uninstallnode()
drop cascades to function _first_cluster.clonenodeprepare(integer,integer,text)
drop cascades to function _first_cluster.clonenodeprepare_int(integer,integer,text)
drop cascades to function _first_cluster.clonenodefinish(integer,integer)
drop cascades to function _first_cluster.storepath(integer,integer,text,integer)
drop cascades to function _first_cluster.storepath_int(integer,integer,text,integer)
drop cascades to function _first_cluster.droppath(integer,integer)
drop cascades to function _first_cluster.droppath_int(integer,integer)
drop cascades to function _first_cluster.storelisten(integer,integer,integer)
drop cascades to function _first_cluster.storelisten_int(integer,integer,integer)
drop cascades to function _first_cluster.droplisten(integer,integer,integer)
drop cascades to function _first_cluster.droplisten_int(integer,integer,integer)
drop cascades to function _first_cluster.storeset(integer,text)
drop cascades to function _first_cluster.storeset_int(integer,integer,text)
drop cascades to function _first_cluster.lockset(integer)
drop cascades to function _first_cluster.unlockset(integer)
drop cascades to function _first_cluster.moveset(integer,integer)
drop cascades to function _first_cluster.moveset_int(integer,integer,integer,bigint)
and 75 other objects (see server log for list)
<stdin>:5: NOTICE: Slony-I: Please drop schema “_first_cluster”
<stdin>:5: NOTICE: drop cascades to 175 other objects
DETAIL: drop cascades to table _first_cluster.sl_node
drop cascades to table _first_cluster.sl_nodelock
drop cascades to table _first_cluster.sl_set
drop cascades to table _first_cluster.sl_setsync
drop cascades to table _first_cluster.sl_table
drop cascades to table _first_cluster.sl_sequence
drop cascades to table _first_cluster.sl_path
drop cascades to table _first_cluster.sl_listen
drop cascades to table _first_cluster.sl_subscribe
drop cascades to table _first_cluster.sl_event
drop cascades to table _first_cluster.sl_confirm
drop cascades to table _first_cluster.sl_seqlog
drop cascades to function _first_cluster.sequencelastvalue(text)
drop cascades to table _first_cluster.sl_log_1
drop cascades to table _first_cluster.sl_log_2
drop cascades to table _first_cluster.sl_log_script
drop cascades to table _first_cluster.sl_registry
drop cascades to table _first_cluster.sl_apply_stats
drop cascades to view _first_cluster.sl_seqlastvalue
drop cascades to view _first_cluster.sl_failover_targets
drop cascades to sequence _first_cluster.sl_local_node_id
drop cascades to sequence _first_cluster.sl_event_seq
drop cascades to sequence _first_cluster.sl_action_seq
drop cascades to sequence _first_cluster.sl_log_status
drop cascades to table _first_cluster.sl_config_lock
drop cascades to table _first_cluster.sl_event_lock
drop cascades to table _first_cluster.sl_archive_counter
drop cascades to table _first_cluster.sl_components
drop cascades to type _first_cluster.vactables
drop cascades to function _first_cluster.createevent(name,text)
drop cascades to function _first_cluster.createevent(name,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text,text,text,text)
drop cascades to function _first_cluster.createevent(name,text,text,text,text,text,text,text,text,text)
drop cascades to function _first_cluster.denyaccess()
drop cascades to trigger _first_cluster_denyaccess on table lottu.synctab
drop cascades to function _first_cluster.lockedset()
drop cascades to function _first_cluster.getlocalnodeid(name)
drop cascades to function _first_cluster.getmoduleversion()
drop cascades to function _first_cluster.resetsession()
drop cascades to function _first_cluster.logapply()
drop cascades to function _first_cluster.logapplysetcachesize(integer)
drop cascades to function _first_cluster.logapplysavestats(name,integer,interval)
drop cascades to function _first_cluster.checkmoduleversion()
drop cascades to function _first_cluster.decode_tgargs(bytea)
drop cascades to function _first_cluster.logtrigger()
drop cascades to trigger _first_cluster_logtrigger on table lottu.synctab
drop cascades to function _first_cluster.terminatenodeconnections(integer)
drop cascades to function _first_cluster.killbackend(integer,text)
drop cascades to function _first_cluster.seqtrack(integer,bigint)
drop cascades to function _first_cluster.slon_quote_brute(text)
drop cascades to function _first_cluster.slon_quote_input(text)
drop cascades to function _first_cluster.slonyversionmajor()
drop cascades to function _first_cluster.slonyversionminor()
drop cascades to function _first_cluster.slonyversionpatchlevel()
drop cascades to function _first_cluster.slonyversion()
drop cascades to function _first_cluster.registry_set_int4(text,integer)
drop cascades to function _first_cluster.registry_get_int4(text,integer)
drop cascades to function _first_cluster.registry_set_text(text,text)
drop cascades to function _first_cluster.registry_get_text(text,text)
drop cascades to function _first_cluster.registry_set_timestamp(text,timestamp with time zone)
drop cascades to function _first_cluster.registry_get_timestamp(text,timestamp with time zone)
drop cascades to function _first_cluster.cleanupnodelock()
drop cascades to function _first_cluster.registernodeconnection(integer)
drop cascades to function _first_cluster.initializelocalnode(integer,text)
drop cascades to function _first_cluster.storenode(integer,text)
drop cascades to function _first_cluster.storenode_int(integer,text)
drop cascades to function _first_cluster.enablenode(integer)
drop cascades to function _first_cluster.enablenode_int(integer)
drop cascades to function _first_cluster.disablenode(integer)
drop cascades to function _first_cluster.disablenode_int(integer)
drop cascades to function _first_cluster.dropnode(integer[])
drop cascades to function _first_cluster.dropnode_int(integer)
drop cascades to function _first_cluster.prefailover(integer,boolean)
drop cascades to function _first_cluster.failednode(integer,integer,integer[])
drop cascades to function _first_cluster.failednode2(integer,integer,bigint,integer[])
drop cascades to function _first_cluster.failednode3(integer,integer,bigint)
drop cascades to function _first_cluster.failoverset_int(integer,integer,bigint)
drop cascades to function _first_cluster.uninstallnode()
drop cascades to function _first_cluster.clonenodeprepare(integer,integer,text)
drop cascades to function _first_cluster.clonenodeprepare_int(integer,integer,text)
drop cascades to function _first_cluster.clonenodefinish(integer,integer)
drop cascades to function _first_cluster.storepath(integer,integer,text,integer)
drop cascades to function _first_cluster.storepath_int(integer,integer,text,integer)
drop cascades to function _first_cluster.droppath(integer,integer)
drop cascades to function _first_cluster.droppath_int(integer,integer)
drop cascades to function _first_cluster.storelisten(integer,integer,integer)
drop cascades to function _first_cluster.storelisten_int(integer,integer,integer)
drop cascades to function _first_cluster.droplisten(integer,integer,integer)
drop cascades to function _first_cluster.droplisten_int(integer,integer,integer)
drop cascades to function _first_cluster.storeset(integer,text)
drop cascades to function _first_cluster.storeset_int(integer,integer,text)
drop cascades to function _first_cluster.lockset(integer)
drop cascades to function _first_cluster.unlockset(integer)
drop cascades to function _first_cluster.moveset(integer,integer)
drop cascades to function _first_cluster.moveset_int(integer,integer,integer,bigint)
and 75 other objects (see server log for list)
完美；一切归零！
：
