![]() ![]() You do NOT need to create a password for the Group role we will create a password for the Login role created later in this document.Įxpand ‘Databases’ > right-click on the database you would like to connect to Chartio > select ‘Properties’. ![]() Give the role a descriptive name > click ‘OK’. In this article we see how POWA can help for optimizing our PostgreSQL database.Connect to your PostgreSQL server instance using pgAdmin > right-click on ‘Group Roles’ and select ‘New Group Role’. Just not that explain analyze will not use the virtual index Conclusion Index Scan using btree_mytab_id on mytab (cost=0.07.20.34 rows=4 width=17) Mydb=# explain select * from mytab where id in (75,25,2014,589) Using explain, we can see that PostgreSQL will use the index. Indexrelid | indexname | nspname | relname | amname Mydb=# SELECT * FROM hypopg_list_indexes() We can verify the existence of the virtual index by Mydb=# select * from hypopg_create_index('create index on mytab (id)') ![]() Let’s create a virtual index in mydb database They do not cost CPU as they don’t exist. ![]() Hypothetical indexes are useful to know if specific indexes can increase performance of a query. We will just note that PostgreSQL uses the extension hypopg to see if the index will be used or no. We can see that an index creation is recommended with the potential gain. Using the tab Index suggestions, we click on Optimize the database. As my load is very low I set my pg_qualstats.sample_rate=1 in the nf file (thanks to Julien Rouhaud) We can now log with the user powa we created at And then we can choose mydb database to monitor it etc]# cat nfĪnd then powa-beb can be started by following command The last step is to configure the powa-web configuration file. In mydb database we create a table mytab and insert in it some rows Let’s again verify extensions into the database mydb Now let’s create a database named mydb for our tests and let’s create all extensions inside the database. Powa | 3.1.1 | public | PostgreSQL Workload Analyser-core Plpgsql | 1.0 | pg_catalog | PL/pgSQL procedural language Pg_stat_statements | 1.4 | public | track execution statistics of all SQL statements executed Pg_stat_kcache | 2.0.3 | public | Kernel statistics gathering Pg_qualstats | 1.0.2 | public | An extension collecting statistics about quals Hypopg | 1.1.0 | public | Hypothetical indexes for PostgreSQL +-+-+-ītree_gist | 1.2 | public | support for indexing common datatypes in GiST We can verify that extensions are loaded in the database using Powa=# CREATE EXTENSION pg_stat_statements The extensions must be created in the repository database and in all databases we want to monitor Postgres=# CREATE ROLE powa SUPERUSER LOGIN PASSWORD 'root' data]# systemctl restart postgresql-9.6.serviceįor POWA configuration, the first step is to create a user for powa Shared_preload_libraries = 'pg_stat_statements,powa,pg_stat_kcache,pg_qualstats' # (change requires restart) data]# grep shared_preload_libraries nf | grep -v ^# Yum install powa_96.x86_64 pg_qualstats96.x86_64 pg_stat_kcache96.x86_64 hypopg_96.x86_64 powa_96-web.x86_64Īfter the installation the nf is modified to load the extensions Rpm -ivh python-tornado-2.2.Īnd then extensions are installed using yum Yum install python-backports-ssl_match_hostname.noarch Just we will note that following packages are installed to resolve some dependencies during the installation of these extensions. This extension can be used to see if PostgreSQL will use the index or no btree_gist : provides GiST index operator classes that implement B-tree equivalent behavior for various data types powa_web : will provide access to powa via a navigator POWA require following extensions: pg_qualstats: gathers statistics on predicates found in WHERE statements and JOIN clauses pg_stat_kcache : gathers statistics about real reads and writes done by the filesystem layer hypopg : extension adding hypothetical indexes in PostgreSQL. extension]# /usr/pgsql-9.6/bin/postgresql96-setup initdb extension]# yum install postgresql96-contrib.x86_64 extension]# yum install postgresql96-server.x86_64 In this present article I am going to show how this powerful tool can help by suggesting indexes which can optimize our queries. In a nice article he shown how this tool can be used to monitor our PostgreSQL. A few time ago my colleague Daniel did a blog about POWA. ![]()
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