count postgres example

POSTGRES-XL is a fully acid-compliant, open-source, easy to scale, multi-tenant security. Support share-nothing; Support massive data parallel processing-mpp (massively Parallel processing). is not very similar to Greenplum. Host Assignment3 host,

In Oracle, deleting a table or deleting a table record; There is a flashback feature that does not require a stop operation and can perfectly retrieve the record. There are, of course, some other recovery tools, such as ODU tools, Gdul tools. can

Seven, Pg_dump: Pg_dump is a tool for backing up the PostgreSQL database. It can even make a full, consistent backup when the database is being used concurrently, without blocking access to the database by other users. The dump format generated by

The latest I/O statistics Tool in CentOS As a Linux system administrator, it is essential to count various types of IO. Iostat is obviously the most important statistical tool. However, iostat is not the focus of this article, because there are

First, restore disk space: In PostgreSQL, data rows that are deleted or updated using the Delete and UPDATE statements are not actually deleted, but only the state of the row is deleted or expired on the physical address of the old version of the

0, password file: Before giving other PostgreSQL client commands, we need to introduce the password file in PostgreSQL. The file is explained here in advance because we are applying the file in a lot of the following sample code to ensure that our

I. restore disk space In PostgreSQL, the data rows deleted or updated using the delete and update statements are not actually deleted, the physical address of the old data row sets the row status to deleted or expired. Therefore, when data in a

When developing Web applications, you often have to add search capabilities. I didn't even know what to search, so I drew a magnifying glass on the sketch. Search is a very important feature, so lucene based tools like Elasticsearch and SOLR become

Running out of disk space in the Pg_xlog directory is a fairly common Postgres problem. This important directory holds the WAL (Write Ahead Log) files. (WAL files contain a record of all changes made to the Database-see the link for more details).

warehouse_db=# CREATE TABLE item (item_id Integer not null,item_name text,item_price numeric,item_data text);CREATE TABLEwarehouse_db=# CREATE INDEX Item_idx on item (ITEM_ID);CREATE INDEXwarehouse_db=# \di Item_idxList of relationsSchema | Name |