On numeric/decimal in postgresql
On numeric/decimal in postgresql
_Recently, the project of data migration for heterogeneous databases is to migrate from postgresql to mysql, which involves the problem of class selection conversion. Among them, numeric has two special lengths, so it needs ...
Posted on Wed, 09 Oct 2019 22:56:22 -0700 by danlindley
The VACUUM command has been enhanced in PG 12 to provide new Option options. This section describes one of the options: INDEX_CLEANUP.
PG 11 vacuum command
[xdb@localhost ~]$ psql -d testdb -p 5433psql (11.2)Type "help" for help.testdb=# \help vacuum;Command: VACUUMDescription: garbage-collect and optionally analyze a databaseSyntax:VACUUM ...
Posted on Mon, 30 Sep 2019 16:53:42 -0700 by tentaguasu
pgbench is a simple program to run benchmarks on PostgreSQL. It may run the same sequence of SQL commands over and over in concurrent database sessions and calculate the average transaction rate (the number of transactions per second). pgbench suppor ...
Posted on Fri, 06 Sep 2019 03:10:30 -0700 by Cyberspace
The experiment was upgraded from pg10 to pg11
1. Source code installation, compiling new version
itm_pg@oracle-> cd postgresql-11.1
Use the new data directory
itm_pg@oracle-> ./configure --prefix=/home/itm_pg/pgsql11.1 --with-pe ...
Posted on Fri, 06 Sep 2019 02:34:44 -0700 by preston_stone
PostgreSQL, Securities, Time Series Data, JSON, HSTORE, Array, range Index, BRIN Block Index, Time Sharing Trend, Linear Regression, MADlib, Machine Learning
The securities industry produces more data, reading and writing is very frequent.
Take stock trading for example, there are thousands of shares in total.There are abou ...
Posted on Mon, 08 Jul 2019 09:15:14 -0700 by WolfRage
oracle data migration to Greenplum has a difficult problem, that is, many stored procedures called storage functions, one by one is too troublesome to change, so if you want to migrate smoothly, one way to compare is to implement functions with the same name and function in greenplum.
1. See if the orafunc plug-in has been installed
Posted on Sat, 29 Jun 2019 18:24:01 -0700 by Walle
PostgreSQL, PostGIS, Composite Index, btree_gist, Shared Bicycle
With the popularity of mobile Internet, spatial data has become the standard of most enterprise data, such as travel, express, etc.
Usually, the query of data will have location distance search, and it will also be accompanied by other attributes filtering, oth ...
Posted on Wed, 19 Jun 2019 15:27:21 -0700 by daniish
PostgreSQL, Time, Space, Object Attributes, Multidimensional Retrieval, Massive, Spatial Index, Data Partition, Block Index BRIN, Multilevel Index, GIN Inverted Index, JSON Index, Multilevel Index, Multilevel Index, Multi-Index Scan Merge, Bitmap And Bitmap Or, Physical Scan, ctid Scan, Interect, Index, Partition Index, Partition Index
Posted on Tue, 11 Jun 2019 11:00:20 -0700 by Joseph Witchard
PostgreSQL , partial index , partition index
When tables are large, you may think of the concept of partitioned tables, such as user tables, which are partitioned into many tables by user ID hash or range.
Another example is the behavior data table, which can be divided into many tables by time.
Benefits of table disassembly ...
Posted on Tue, 11 Jun 2019 10:53:16 -0700 by smordue
Postgresql/Greenplum data base There are two ways to implement aggregation functions: HashAggregate and GroupAggregate.
We now analyze the differences between the two aggregations and their application scenarios through a simplest sql.
select count(1) from pg_class group by oid;
1. Comparisons of two implementation algorithms:
Posted on Sun, 09 Jun 2019 16:30:01 -0700 by hagman