pgspider 集成hypopg 虚拟索引扩展

Posted 2020-11-26 rongfengliang

虚拟索引是不占用空间的，可以用来方便的进行sql 查询的性能评估，帮助我们了解查询优化的效果
hypopg 是一个pg 扩展，提供了比较方便的函数，我们可以用来评估查询，以下是pgspider 集成hypopg
的一个学习

环境准备

• dockerfile
  使用docker 运行，参考我的相关连接

 

FROM dalongrong/pgspider:base as build

WORKDIR /app

RUN apt-get update && apt-get install -y automake autoconf libtool pkg-config libssl-dev

RUN git clone https://github.com/HypoPG/hypopg.git /app/postgresql-11.6/contrib/hypopg

RUN git clone https://github.com/powa-team/pg_qualstats.git /app/postgresql-11.6/contrib/pg_qualstats

RUN cd /app/postgresql-11.6/contrib/hypopg && make && make install

RUN cd /app/postgresql-11.6/contrib/pg_qualstats && make && make install

?

FROM debian:stretch-slim

ENV GOSU_VERSION 1.11

RUN apt-get update && apt-get install -y wget libreadline-dev

# explicitly set user/group IDs

RUN set -eux; 

 groupadd -r postgres --gid=999; 

# https://salsa.debian.org/postgresql/postgresql-common/blob/997d842ee744687d99a2b2d95c1083a2615c79e8/debian/postgresql-common.postinst#L32-35

 useradd -r -g postgres --uid=999 --home-dir=/var/lib/postgresql --shell=/bin/bash postgres; 

# also create the postgres user‘s home directory with appropriate permissions

# see https://github.com/docker-library/postgres/issues/274

 mkdir -p /var/lib/postgresql; 

 chown -R postgres:postgres /var/lib/postgresql

?

RUN wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$(dpkg --print-architecture)" 

   && chmod +x /usr/local/bin/gosu 

   && gosu nobody true

# make the "en_US.UTF-8" locale so postgres will be utf-8 enabled by default

RUN set -eux; 

   if [ -f /etc/dpkg/dpkg.cfg.d/docker ]; then 

   # if this file exists, we‘re likely in "debian:xxx-slim", and locales are thus being excluded so we need to remove that exclusion (since we need locales)

   grep -q ‘/usr/share/locale‘ /etc/dpkg/dpkg.cfg.d/docker; 

   sed -ri ‘//usr/share/locale/d‘ /etc/dpkg/dpkg.cfg.d/docker; 

   ! grep -q ‘/usr/share/locale‘ /etc/dpkg/dpkg.cfg.d/docker; 

   fi; 

   apt-get update; apt-get install -y locales; rm -rf /var/lib/apt/lists/*; 

   localedef -i en_US -c -f UTF-8 -A /usr/share/locale/locale.alias en_US.UTF-8

ENV LANG en_US.utf8

?

# install "nss_wrapper" in case we need to fake "/etc/passwd" and "/etc/group" (especially for OpenShift)

# https://github.com/docker-library/postgres/issues/359

# https://cwrap.org/nss_wrapper.html

RUN set -eux; 

   apt-get update; 

   apt-get install -y --no-install-recommends libnss-wrapper; 

   rm -rf /var/lib/apt/lists/*

?

RUN mkdir /docker-entrypoint-initdb.d

COPY --from=build /usr/local/pgspider /usr/local/pgspider

RUN sed -ri "s!^#?(listen_addresses)s*=s*S+.*!1 = ‘*‘!" /usr/local/pgspider/share/postgresql/postgresql.conf.sample; 

   grep -F "listen_addresses = ‘*‘" /usr/local/pgspider/share/postgresql/postgresql.conf.sample

RUN echo "shared_preload_libraries = ‘pg_qualstats‘" >> /usr/local/pgspider/share/postgresql/postgresql.conf.sample

RUN mkdir -p /var/run/postgresql && chown -R postgres:postgres /var/run/postgresql && chmod 2777 /var/run/postgresql

ENV PATH $PATH:/usr/local/pgspider/bin

ENV PGDATA /var/lib/postgresql/data

RUN mkdir -p "$PGDATA" && chown -R postgres:postgres "$PGDATA" && chmod 777 "$PGDATA"

VOLUME /var/lib/postgresql/data

COPY docker-entrypoint.sh /usr/local/bin/

RUN ln -s usr/local/bin/docker-entrypoint.sh / # backwards compat

ENTRYPOINT ["docker-entrypoint.sh"]

?

EXPOSE 5432

CMD ["postgres"]

 

• docker-compose 文件
  构建好的镜像已经push docker hub 了，所以直接使用docker-compose 运行

version: "3"

services: 

  pg:

   image: dalongrong/pgspider:hypopg-pg_qualstats

   ports:

   - "5432:5432"

   environment: 

   - "POSTGRES_PASSWORD=dalong"

• 启动

docker-compose up -d

试用

• 创建扩展

 CREATE EXTENSION hypopg;

• 创建测试数据

CREATE TABLE hypo AS SELECT id, ‘line ‘ || id AS val FROM generate_series(1,10000) id;

• 查询计划查看

EXPLAIN SELECT * FROM hypo WHERE id = 1;

 

 

• 添加虚拟索引
  使用提供的函数

 

SELECT * FROM hypopg_create_index(‘CREATE INDEX ON hypo (id)‘);

• 查询已经创建的虚拟索引

SELECT * FROM hypopg_list_indexes();

 

 

 

• 查询计划分析

EXPLAIN SELECT * FROM hypo WHERE id = 1;

 

效果

 

 

• 查看查询计划并执行

EXPLAIN ANALYZE SELECT * FROM hypo WHERE id = 1;

 

 

 

说明

使用hypopg 扩展你的好处是我们不需要花费空间以及多大的时间，就可以通过慢慢试错同时不影响环境的情况下，进行
sql 的优化调整，是一个很不错的扩展工具

参考资料

https://github.com/HypoPG/hypopg
https://rjuju.github.io/postgresql/2015/07/02/how-about-hypothetical-indexes.html
https://hypopg.readthedocs.io/en/latest/
https://github.com/rongfengliang/pgspider-docker/blob/master/Dockerfile-hypopg-pg_qualstats