PostgreSQL pg_clickhouse插件的安装和使用
clickhouse公司开发的pg_clickhouse可以由PostgreSQL数据库调用clickhouse数据库的能力，实现快速的查询。
我按照pg_clickhouse文档的提示，完成了docker镜像下载、容器的运行等步骤。
- docker镜像下载
文档中的命令行是
docker pull ghcr.io/clickhouse/pg_clickhouse:18-0.1.0国内用官方地址下载较慢，还容易中断。可以用南京大学镜像快速下载。
docker pull ghcr.nju.edu.cn/clickhouse/pg_clickhouse:18-0.1.0 Trying to pull ghcr.nju.edu.cn/clickhouse/pg_clickhouse:18-0.1.0... Getting image source signatures Copying blob 1733a4cd5954 done Copying blob 72fdf866b594 done Copying blob 6dd6fcdc9495 done Copying blob bab3dfaacd57 done Copying blob b004922a6f45 done Copying blob c3ff19dd627c done Copying blob 854c622dacff done Copying blob f106a4619ad3 done Copying blob c063aa26ba0a done Copying blob 1a285618a7ed done Copying blob 807997f7ba63 done Copying blob db5e628b821e done Copying blob e6b94ae4e71a done Copying blob 1dc30afa2762 done Copying blob 9b8b3f5bc3de done Copying blob 124c105132bf done Copying blob 55be4826f873 done Copying blob 18fe35f0abfa done Copying config 5cb0431c68 done Writing manifest to image destination Storing signatures 5cb0431c686e00a8fb24d4a5c80d3102bcbab366c5a2e1da2e9d344477e3b006- 运行容器
首次运行用docker run命令，并创建插件。
docker run --name pg_clickhouse -e POSTGRES_PASSWORD=my_pass -d ghcr.nju.edu.cn/clickhouse/pg_clickhouse:18 docker exec -it pg_clickhouse psql -U postgres -c 'CREATE EXTENSION pg_clickhouse'以后再次运行，只要docker start启动容器，docker exec -it登录即可
dockerstartpg_clickhouse pg_clickhouse dockerexec-it pg_clickhouse psql-U postgres psql(18.1(Debian18.1-1.pgdg13+2))Type"help"forhelp.postgres=# CREATE SERVER taxi_srv FOREIGN DATA WRAPPER clickhouse_fdwOPTIONS(driver'binary',host'localhost',dbname'taxi');CREATESERVER postgres=# CREATE USER MAPPING FOR CURRENT_USER SERVER taxi_srvOPTIONS(user'default');CREATEUSERMAPPING postgres=# CREATE SCHEMA taxi;CREATESCHEMApostgres=# IMPORT FOREIGN SCHEMA taxi FROM SERVER taxi_srv INTO taxi;ERROR: pg_clickhouse: connection error: failtoconnect: Connection refused前几步都没有报错，导入SCHEMA报错了，应该是缺少一个运行中的clickhouse服务器。