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PostgreSQL Replication, Second Edition

PostgreSQL Replication, Second Edition

By : Hans-Jürgen Schönig
4.5 (4)
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PostgreSQL Replication, Second Edition

PostgreSQL Replication, Second Edition

4.5 (4)
By: Hans-Jürgen Schönig

Overview of this book

This book is ideal for PostgreSQL administrators who want to set up and understand replication. By the end of the book, you will be able to make your databases more robust and secure by getting to grips with PostgreSQL replication.
Table of Contents (17 chapters)
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16
Index

Creating tables and issuing queries


After this introduction to Postgres-XC and its underlying ideas, it is time to create our first table and see how the cluster will behave. The next example shows a simple table. It will be distributed using the hash key of the id column:

test=# CREATE TABLE t_test (id int4)
DISTRIBUTE BY HASH (id);
CREATE TABLE
test=# INSERT INTO t_test
SELECT * FROM generate_series(1, 1000);
INSERT 0 1000

Once the table has been created, we can add data to it. After completion, we can check whether the data has been written correctly to the cluster:

test=# SELECT count(*) FROM t_test;
count
-------
  1000
(1 row)

Not surprisingly, we have 1,000 rows in our table.

The interesting thing here is to see how the data is returned by the database engine. Let's take a look at the execution plan of our query:

test=# explain (VERBOSE TRUE, ANALYZE TRUE,
NODES true, NUM_NODES true)
SELECT count(*) FROM t_test;
QUERY PLAN
-------------------------------------------------------
 Aggregate...

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