今天有部分数据被同事放到redis上面了，需要同步过来。发现pg有连接redis插件，就参考德哥的文章（https://yq.aliyun.com/articles/14609）安装了一下，不过也遇到一些原文没有遇到问题。下面是我的安装过程：
首先redis_fdw有不同的branch，要根据自己的pg版本下载不同的branch
这里下载的是
redis_fdw-REL9_5_STABLE.zip
redis相关的库
hiredis-master.zip
解压后安装
cd hiredis
make
make PREFIX=/data/redis_fdw/hiredis_bin install
修改redis_fdw的Makefile
vi Makefile
# 末尾追加
LDFLAGS += -L/data/redis_fdw/hiredis_bin/lib
安装redis_fdw
source /home/pg9.5.2/.bash_profile
make USE_PGXS=1
参考德哥的博客安装的，死活报如下错误
redis_fdw.c: In function ‘redis_fdw_handler’:
redis_fdw.c:276: warning: assignment from incompatible pointer type
redis_fdw.c: In function ‘redisGetForeignPaths’:
redis_fdw.c:797: error: too many arguments to function ‘create_foreignscan_path’
redis_fdw.c: In function ‘redisGetForeignPlan’:
redis_fdw.c:833: error: too many arguments to function ‘make_foreignscan’
make: *** [redis_fdw.o] Error 1
反复换了各种版本redis_fdw的branch还是报错，其实上面的意思
上述的错误是指对应行的函数参数多了，我们删除几个，空值的参数
第一个函数删除一个NULL参数
第二个函数删除两个NIL参数
再次编译通过（
不要问我为什么，就是这么简单:)）
make USE_PGXS=1 install
继续安装
[
pg9.5.2@postgres ~]$ psql -dpostgres -Upostgres -p5432
psql (9.5alpha2)
Type "help" for help.
postgres=# create extension redis_fdw;
ERROR: could not load library "/opt/pgsql9.5.2/lib/redis_fdw.so": libhiredis.so.0.12: cannot open shared object file: No such file or directory
修改库地址
shared_preload_libraries = '/opt/pgsql9.5.2/lib/redis_fdw'
启动还是报错
[
pg9.5.2@postgres pg9.5.2data]$ FATAL: XX000: could not load library "/opt/pgsql9.5.2/lib/redis_fdw.so": libhiredis.so.0.12: cannot open shared object file: No such file or directory
LOCATION: internal_load_library, dfmgr.c:239
把这些库考进来
cp * /opt/pgsql9.5.2/lib/
启动依然报上面的错误
修改权限：chown pg9.5.2:pg9.5.2 *
启动成功
[
pg9.5.2@postgres pg9.5.2data]$ pg_ctl restart
pg_ctl: PID file "/data/pg9.5.2data/postmaster.pid" does not exist
Is server running?
starting server anyway
server starting
[
pg9.5.2@postgres pg9.5.2data]$ LOG: 00000: redirecting log output to logging collector process
HINT: Future log output will appear in directory "pg_log".
LOCATION: SysLogger_Start, syslogger.c:622
继续操作
[
pg9.5.2@postgres ~]$ psql -dpostgres -Upostgres -p5432
psql (9.5alpha2)
Type "help" for help.
postgres=# create extension redis_fdw;
CREATE EXTENSION
postgres=# CREATE SERVER redis_server
postgres-# FOREIGN DATA WRAPPER redis_fdw
postgres-# OPTIONS (address '127.0.0.1', port '6379');
CREATE SERVER
postgres=# CREATE FOREIGN TABLE redis_db0 (key text, val text)
postgres-# SERVER redis_server
postgres-# OPTIONS (database '0');
CREATE FOREIGN TABLE
postgres=# CREATE USER MAPPING FOR PUBLIC
postgres-# SERVER redis_server
postgres-# OPTIONS ();
ERROR: syntax error at or near ")"
LINE 3: OPTIONS ();
^
如果是无密码就写成空，但password参数还是需要的
postgres=# CREATE USER MAPPING FOR PUBLIC
postgres-# SERVER redis_server
postgres-# OPTIONS (password '');
CREATE USER MAPPING
postgres=# CREATE FOREIGN TABLE myredishash (key text, val text[])
postgres-# SERVER redis_server
postgres-# OPTIONS (database '0', tabletype 'hash', tablekeyprefix 'pack_config:');
CREATE FOREIGN TABLE
postgres=# select * from myredishash limit 10;
key | val
-------------------------------------------+---------------------------------------------------
------------------------------------------------
pack_config:2160070603:app:15158180750 | {1,"2016-06-08 15:46:23"}
pack_config:2160150608:app:18970345322 | {1,"2016-06-11 13:20:24"}
pack_config:2160150608:app:13777834990 | {1,"2016-06-16 15:09:18"}
pack_config:2160320622:app:13857143019 | {0,"2016-06-24 15:40:01"}
pack_config:2160070603:app:13575478184 | {1,"2016-06-04 19:23:06"}
pack_config:2160050527:app:13023698286 | {1,"2016-06-02 07:41:49"}
pack_config:2160150608:app:15382332310 | {4,"2016-06-09 08:15:12"}
pack_config:2160220616:wechat:13867456883 | {1,"2016-06-24 13:14:13",2,"2016-06-24 13:14:19",4
,"2016-06-24 13:14:30"}
pack_config:2160150608:app:13588335935 | {2,"2016-06-11 15:32:51",1,"2016-06-11 15:33:33"}
pack_config:2160150608:app:18755998181 | {1,"2016-06-16 09:53:42",2,"2016-06-16 09:53:45",3
,"2016-06-16 09:53:46",4,"2016-06-16 09:53:48"}
(10 rows)
postgres=# select * from myredishash where key like '%15158180750%';
key | val
----------------------------------------+---------------------------
pack_config:2160070603:app:15158180750 | {1,"2016-06-08 15:46:23"}
(1 row)
postgres=# select count(*) from myredishash
;
count
-------
10
(1 row)
参考文章：
https://yq.aliyun.com/articles/14609
