PostgreSQL is a powerful, enterprise class, open source RDBMS. It has more than 15 years of active development and a proven architecture that has earned it a strong reputation for reliability and data integrity. It runs on all major operating systems, including Linux, UNIX and Windows. It prides ...

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6
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2answers
17k views

List the database privileges using psql

I'm in the middle of a database server migration and I can't figure (after googling and searching here) how can I list the database privileges (or all the privileges across the server) on PostgreSQL ...
6
votes
1answer
968 views

Postgres functions vs prepared queries

I'm sure it's there but I've not been able to find a simple definitive answer to this in the docs or via Google: In Postgres, are prepared queries and user defined functions equivalent as a ...
6
votes
2answers
461 views

PostgreSQL Complete Database Backup

I've been trying to figure out how I can completely backup my PostgreSQL database. I have not seen any resource that explains how to do a complete backup. I am aware of the pg_dump and pg_dumpall ...
6
votes
3answers
2k views

How to version control PostgreSQL schema with comments?

I version control most of my work with Git: code, documentation, system configuration. I am able to do that because all my valuable work is stored as text files. I have also been writing and dealing ...
6
votes
2answers
248 views

Improve performance of COUNT/GROUP-BY in large PostgresSQL table?

I am running PostgresSQL 9.2 and have a 12 column relation with about 6,700,000 rows. It contains nodes in a 3D space, each one referencing a user (who created it). To query which user has created how ...
6
votes
2answers
832 views

Seeting up a PostgreSQL database on another hard drive than my system one on OS X?

I am on OS X 10.8.3, I've install PostgreSQL from macports, but I've realized that I have not enough space on my system drive for the DB I am about to populate with data. Is there a way to create new ...
6
votes
2answers
3k views

How to promote an existing index to primary key in PostgreSQL

I know how to make a primary key within a table, but how do I make an existing index a primary key? I'm trying to copy an existing table from one database to another. When I show the table, the index ...
6
votes
4answers
3k views

Finding empty columns of a table in PostgreSQL

What query would return the name of the columns of a table where all rows are NULL?
6
votes
3answers
3k views

What can I do with the new json field?

PostgreSQL 9.2 introduced the json field type. Why and when should I use it? What benefits does it have over a text field? I thought there were new query options available, however I haven't seen ...
6
votes
1answer
1k views

EC2 - How to correctly back up PostgreSQL data?

Here is the setup: 1 small Amazon Linux (EBS-backed) EC2 instance with 3 additional volumes. This is both a web server and database server. One volume for code, one for the PostgreSQL (8.4) data ...
6
votes
1answer
20k views

How do I reset the postgres password for PostgreSQL on Windows?

I have installed PostgreSQL on my Windows machine for development. Now I haven't used it for a while, and have forgotten the password for user postgres (default admin user in PostgreSQL). How can I ...
6
votes
3answers
2k views

PostgreSQL: Creation date of a table

I've recently finished a project, during which many DB tables were created. Most of these tables contain temporary garbage, and I am looking for a simple way to list all these tables. Is there a ...
6
votes
3answers
16k views

How to run psql on Mac OS X?

I installed PostgreSQL on a computer with Mac OS X using the One click installer. Then I try to access PostgreSQL using the psql command, but it doesn't seem to be available. I get this message: ...
6
votes
2answers
4k views

Optimizing bulk update performance in Postgresql

Using PG 9.1 on Ubuntu 12.04. It currently takes up to 24h for us to run a large set of UPDATE statements on a database, which are of the form: UPDATE table SET field1 = constant1, field2 = ...
6
votes
3answers
2k views

Set names to attributes when creating JSON with row_to_json

Is it possible to rename default f1, f2, f3... names when using row_to_json function for only some columns? I can do row_to_json(customers) returning ...
6
votes
2answers
1k views

PostgreSQL: reuse of complex intermediate result in same query

Using PostgreSQL (8.4), I'm creating a view that summarizes various results from a few tables (e.g creating columns a, b, c in the view), and then I need to combine some of these results together in ...
6
votes
1answer
358 views

Can PostgreSQL tell me what configuration files it's using?

I am having trouble with some changes I'm making to a configuration file. I think PostgreSQL is not using the ones I'm modifying. Is there any way to get postgres (maybe some environment variable) to ...
6
votes
1answer
194 views

Privileges required to install PostgreSQL

I am new to PostgreSQL Database. I need to install it in my machine. I am not administrator in my system. Can some one suggest, if Non-Administrator can install it. If there is any other way of ...
6
votes
1answer
3k views

PostgreSQL: COUNT(*) uses a sequential scan, not index

Why does PostgreSQL sequentially scans the table for COUNT(*) query, while there is a very small and indexed primary key?
6
votes
1answer
354 views

PostgreSQL “freeze”/“unfreeze” command equivalents

In Derby (an embedded database written in Java which is mostly used for testing or prototyping) there are "freeze" and "unfreeze" commands which can be used during an online backup. "Freeze" simply ...
6
votes
1answer
157 views

How should we handle rows which won't be queried once they are old in PostgreSQL?

We have a table in a PostgreSQL database which is growing on the order of millions of rows per day. Each row consists of: ID Foreign user ID Date and time Other data The date and time aren't ...
6
votes
1answer
501 views

PostgreSQL partition hierarchy design for centralized logging

I am looking into setting up logging from all of my servers into a centralized postgresql database. It makes sense to be able to drop logs by date or by host, so I'd like to set it up with ...
6
votes
4answers
2k views

Determine when a PostgreSQL database was last changed

I'm looking at altering how backups are done and am wondering if there is a way to determine which databases in a postgreql cluster have not been recently changed? Instead of using pg_dumpall, I'd ...
6
votes
2answers
72 views

Index that is not used, yet influences query

I've got a PostgreSQL 9.3 table with some numbers and some additional data: CREATE TABLE mytable ( myid BIGINT, somedata BYTEA ) This table currently has about 10M records and takes 1GB of ...
6
votes
1answer
128 views

What happens in PostgreSQL checkpoint?

Here's part of my checkpoint log: 2014-03-26 11:51:29.341 CDT,,,18682,,532854fc.48fa,4985,,2014-03-18 09:15:24 CDT,,0,LOG,00000,"checkpoint complete: wrote 15047 buffers (1.4%); 0 transaction log ...
6
votes
2answers
258 views

Is this temp table behaviour documented?

Query Language (SQL) and PL/pgSQL functions treat temp tables differently: begin; create table foo(id) as values (1); select * from foo; /* id ---- 1 */ savepoint s; create function f() returns ...
6
votes
1answer
302 views

Optimizing PostgreSQL for transient data

I have several tables with 100-300 columns of integer types each, that hold highly volatile data. The datasets are keyed by one or two primary keys, and when refresh occurs, the whole dataset is ...
6
votes
1answer
1k views

Postgresql performed a “fast shutdown” by itself. Why? How was it able to do that?

I've already googled and manual read as much as I could before posting this here. Version info: Postgres8.4 on Ubuntu10.x I have a personal laptop that I run a postgres server on, and a Java script ...
6
votes
3answers
1k views

Postgres, MVCC, and Locking

I have a series of SQL statements that look like the following: BEGIN; SELECT counter FROM table WHERE id=X FOR UPDATE; REALLY COMPLEX QUERY; UPDATE table SET counter=Y WHERE id=X; END; I'd like to ...
6
votes
2answers
1k views

PostgreSQL: Can I do pg_start_backup() on a live, running db under load?

Our established replication has broken ("requested WAL segment has already been removed" during downtime) We cannot easily stop the master again. Can we do pg_start_backup(), rsync ${PGDATA}/ ...
6
votes
2answers
513 views

PostgreSQL PITR restore

I have a PostgreSQL 9.1 server running on a CentOS 5.8 32bit OS and I have enabled WAL archiving. On this server, there are three databases: databaseA, databaseB and databaseC. Someone deletes a ...
6
votes
1answer
260 views

in postgres, can one optimize a table across partitions?

in a database with many companies, segregating them using schema and search_path almost all access comes at the company level, that is, limited to a single schema. some data-warehouse and accounting ...
6
votes
4answers
4k views

No NULLs, yet invalid byte sequence for encoding “UTF8”: 0x00

I've spent the last 8 hours trying to import the output of 'mysqldump --compatible=postgresql' into PostgreSQL 8.4.9, and I've read at least 20 different threads here and elesewhere already about this ...
6
votes
1answer
147 views

Can we use old primary to sync with standby after failover in PostgreSQL?

If my standby (postgres) is behind by few seconds before failover. What is the easiest way to sync back my old primary after failover in PostgreSQL. In Oracle we have the option of Reinstating a ...
6
votes
2answers
116 views

Inconsistency in repeatable read

http://www.postgresql.org/docs/9.2/static/transaction-iso.html The Repeatable Read mode provides a rigorous guarantee that each transaction sees a completely stable view of the database. However, ...
6
votes
3answers
229 views

Is using SUM() twice suboptimal?

I know I have to write SUM twice, if I wish to use it in a HAVING clause (or use a derived table otherwise): SELECT id, sum(hours) AS totalhours FROM mytable GROUP BY id HAVING sum(hours) ...
6
votes
1answer
138 views

What is a good way to determine the performance I should expect from a PostgreSQL server?

Trying to figure out how I should expect my database to perform. Basically, I need to determine when the server I have set up is reaching its performance limits - which would help me plan server ...
6
votes
1answer
294 views

Storing logs on per day basis in PostgreSQL

Requirements here are to store historical logs. For the sake of simplicity I'll assume this sample scenario where we are selling some products on our website and we need to keep records of sales of ...
6
votes
1answer
694 views

PostgreSQL data type text vs varchar without length

In PostgreSQL you can create a column with data type character varying (without length precision) or text like this: ALTER TABLE test ADD COLUMN c1 varchar; ALTER TABLE test ADD COLUMN c2 text; Is ...
6
votes
2answers
130 views

Altering db schema in production environment

I have some questions on db schema changes in production environment without taking the database server and the webapp offline. Q1- I want to be able to make changes to database schema (adding, ...
6
votes
1answer
551 views

TPS too high in PostgreSQL

I created a table: CREATE TABLE foo ( id integer primary key, bar integer NOT NULL ); and inserted one row: INSERT INTO foo (id, bar) VALUES (1, 1); and ran a pgbench of the following ...
6
votes
2answers
227 views

Postgres performance difference on insert

I was tried to partition one large table, and come with such Postgres behavior that I could not explain. Maybe you will have any suggestions? I went quite straight forward way (i know that it is not ...
6
votes
1answer
2k views

Could too many idle connections affect PostgreSQL 9.2 performance?

Some queries on my database server seem to take a long time to respond, and I believe the CPU usage is high. When running ps aux, I see ~250 "idle" connections (which I believe to be too many). I ...
6
votes
1answer
125 views

Can I get the union of the a Postgres fulltext index?

I have a fulltext index on a table. Is it possible to retrieve the set of terms used in the index (gist or gin)? With weights if possible? To clarify: If I have the following table: create table ...
5
votes
4answers
2k views

Why are so many MPP solutions based on PostgreSQL instead of MySQL?

Astor Data, Greenplum and GridSQL all allow Massive Parallel Processing of SQL queries. They are also all built around PostgreSQL technology. Is this just because of licensing issues or are there ...
5
votes
3answers
117 views

Filtering data that could have more than one category

I have a table like the following: Annotation ( document, term, category ) Where document and term are some ID, while category is an integer. The couple document - term is not unique, ...
5
votes
3answers
2k views

Postgres Write Performance on Intel S3700 SSD

I'm not seeing the Postgres write performance increases I thought I would with a single SSD vs a hardware RAID 10 array of (16) 15k RPM SAS drives. I have a Dell R820 with a PERC H700 hardware RAID ...
5
votes
2answers
414 views

Custom unique column constraint, only enforced if one column has a specific value

Is it possible to have a custom unique column constraint as follows? Suppose I have two cols, subset and type, both strings (though the data types probably doesn't matter). If type is "true", then ...
5
votes
2answers
1k views

Postgresql 9 speeding up indexed inserts (JPA)

I have an application which generates a lot of data which needs to be inserted quickly (something around 13million records). I use JPA 2.0/Hibernate with Postgres 9.1, and I managed to achieve quite a ...
5
votes
5answers
2k views

Altering table schema takes too much time

I am using PostgreSQL database. I have a table with millions of rows. I have a varchar column with 2000 size and i want to make it to 4000. I ran the alter table command, but it is taking too much ...