PostgreSQL is an enterprise class, open-source, object-relational database management system (ORDBMS) available for all major platforms including Linux, UNIX, Windows and OS X. Please mention your exact PostgreSQL version when asking questions.

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3
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0answers
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What happen when Postgresql tablespace is null?

I'm facing a DWH on postgresql with no DBA (I'm not one) so I turn to you with hope to figure this issue/s. Long story short, when I check the disk usage per tablespace, I get different distribution ...
-2
votes
1answer
461 views

Use select query in stored procedure

I have some questions about stored procedures. Using select query inside the stored procedure is efficent or using select query in front end. Which is take less time and give the result is fast or if ...
0
votes
1answer
158 views

PostgreSQL created a PostgreSQL user on mac. Is this necessary?

I just installed PostgreSQL on a Mac (Mountain Lion) today. The installer created a mac user PostgreSQL on my machine. After installation, the user still exists. My question is that why postgreSQL ...
17
votes
1answer
5k views

How can I benchmark a PostgreSQL query?

I want to benchmark a query containing an user-defined function I have written for PostgreSQL. Are there any standard ways to run such a benchmark? I know that timing can be turned on with \timing ...
1
vote
1answer
628 views

How to monitor or do vacuum without stop all?

I have postgres9.1 I try to run full vacuum on a specific table , but it run for more than 5 hours. I stop all process against this table and i cannot have the process down any longer. Is there a ...
4
votes
1answer
213 views

How to view the full, flattened query underlying a Postgresql view?

If I have a view on a view on a view (etc.), is there a way to show the full query that this expands/flattens to?
0
votes
1answer
613 views

createdb command error : could not connect to database [closed]

I am using the following command for creating database in postgresql. createdb -D pg_default -E UTF8 -h localhost -p 5432 -U pramil -W pramil mydb but this command results prompt for password.When ...
6
votes
2answers
2k 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 ...
2
votes
1answer
517 views

Encryption in PostgreSQL

Does PostgreSQL support data encryption features at transactional and the table level of database? If yes, how? Oracle provides this via database and network encryption. Oracle provides encryption at ...
0
votes
1answer
158 views

Syntax error when trying to import database from two PostgreSQL databases

Following on from this prior question, I'm trying to export a database from one server and put it on another using phpPgAdmin. My process is like this: select the database in server 1 and hit the ...
0
votes
0answers
2k views

createdb: could not connect to database postgres: FATAL: could not write init file [closed]

RedHat Enterprise Server 3.0 32 Bits psql (PostgreSQL) 8.2.3 user: postgres server is running: /soft/postgres/8.2.3/bin/pg_ctl start pg_ctl: another server may be running; trying to start server ...
3
votes
2answers
475 views

General tool to load dump files [closed]

I am a big fan of Postgres both for its price but also for its features. I am going to have to need to upload into it both Oracle dump and SQL Server files. I will try to ask and beg for plain .csv ...
1
vote
1answer
199 views

Restrict access for Windows administrator in PostgreSQL

Is there a way to protect PostgreSQL from user with Windows administrator rights? Like this question but for Postgres.
1
vote
2answers
212 views

Group Database Entries by time difference

I have a large postgreSQL database with log data. All this data has timestamps and I want to group consecutive rows where the difference between the timestamps is less then 1500 miliseconds for ...
0
votes
1answer
125 views

Writing with multiple psql processes to database seems to damage data

I have a couple terabytes of CSV data that I am trying to import into a PostgreSQL 8.4 database (on a RedHat 6.2 server), whose data directory is initialized on a multipath hardware RAID. There are ...
2
votes
1answer
1k views

Is replication from SQL Server 2008 to PostgreSql possible?

Is it possible ? Sql Server as publisher(master) and PostgreSql as slave(subscriber) ? Any type of replication really.
0
votes
1answer
1k views

pg_dump from 9.2 to 8.4 [closed]

I'm trying to restore a db dump from PostgreSQL 9.2 to PostgrSQL 8.4 (from separate machines, both are running Windows 7). I followed the instructions in this answer: Use pg_restore to restore from ...
3
votes
1answer
745 views

Is it safe to call pg_ctl reload while doing heavy writes?

I am running Postgres 8.4, and I would like to change the authentication method for a user. It's my understanding that I have to do this in pg_hba.conf, and then reload the configuration files with ...
2
votes
1answer
5k views

Select first row (grouping) + add aggregate function

First have a look at this question on StackOverflow. I'm looking to accomplish the same task, except I also need to add an aggregate function (PostGIS's ST_Union) to my query. How can I combine the ...
0
votes
2answers
26k views

Can't connect to the postgres server ls: /tmp/.s.PGSQL.5432: No such file or directory

*Update*I included an update at the bottom of this post with details from the logs explaining the problem that I haven't been able to fix. Following along with this Railscast ...
2
votes
2answers
2k views

Changing PostgreSQL port using command line

My PostgreSQL default port is 5432, I want to change default port by using command line (in Windows 7). I saw this solution before: http://stackoverflow.com/questions/187438/want-to-change-pgsql-port ...
1
vote
4answers
2k views

Daily and Differential Backups [closed]

Is there a program with which I can create daily MySQL, PostgreSQL and MariaDB backups with these requirements: The first time, make a full backup. The second time, only the changes since the last ...
2
votes
1answer
1k views

Use cases for hstore vs json datatypes in postgresql [closed]

In Postgresql, the hstore and json datatypes seem to have very similar use cases. When would you choose to use one vs. the other? Initial thoughts: You can nest with json; you can't with hstore ...
2
votes
4answers
3k views

Database design - People and Organisations

Databases are not my primary skill and I am finding I need some assistance please. The software we are building has "Customers". The Customer could either be a Person or an Organisation. I really ...
5
votes
1answer
298 views

force PostgreSQL into recovery mode

I have a somewhat strange question. Is there a way to manually force PostgreSQL into recovery mode? I've not been able to find aything in the documentation. I've been working with a script ...
3
votes
1answer
115 views

Why do psql queries take longer when inserting many rows. Why is it non linear

So if I insert a single row into a postgres database it takes 18 ms. If I do this in a loop like this: INSERT INTO contacts (numbers) SELECT distinct array[ (random() * 99999999)::integer, ...
1
vote
1answer
821 views

Foreign Key to Multicolumn Primary Key?

I have three connected table in my design. Basic logic is when a category deleted, also delete records in category_product table which has deleted category's id in its cat_id column. But when I tried ...
0
votes
1answer
248 views

Postgres - Schema information within Trigger?

Background : (Multi-tenant design;separate schema per customer, all table structures identical;Data-warehouse / non-OLTP system here; Postgres 9.2.x). Reviewing patterns for the following problem: I ...
0
votes
1answer
190 views

OK to put temp tablespace on volatile storage or to omit it from backups? (Postgresql)

I would intuit that it's fine, but I just want to make sure there are no gotchas from a recovery point of view: If I were to lose my temp tablespace upon system crash, would this prevent proper crash ...
1
vote
0answers
109 views

PostgreSQL datasource URL?

My first attempt to use PostgreSQL: I have the elephant icon on the top right: running on port 5432. I want to use LibreOffice as an interface: Connect to an existing database: PostgreSQL ...
1
vote
1answer
1k views

PostgreSQL stored function that returns arbitrary resultset

I would like to write a PostgreSQL stored function that essentially behaves like the stored procedures I know and love from MSSQL and MySQL where I can just wrap a query that takes no parameters and ...
2
votes
2answers
983 views

Read Committed Isolation Level

Quote from docs: Read Committed is the default isolation level in PostgreSQL. When a transaction uses this isolation level, a SELECT query (without a FOR UPDATE/SHARE clause) sees only data ...
2
votes
1answer
12k views

Performance difference between MySQL and PostgreSQL for the same schema/queries [closed]

I'm a newbie DBA, and I have experience in Microsoft SQL Server but I want to jump to FLOSS. I'm starting a company, and we develop an app (PHP) with a Postgres backend, and we did some tests ...
1
vote
1answer
406 views

Table for optional parent/child relationship

Assuming we have the following table: Item, Parent, Child and Parent is the parent of child. The item can either belong to a parent or child and not both. I have other tables that are similar to ...
0
votes
0answers
361 views

PostgreSQL: Slave doesn't replicate the Master's data

I'm using PostgreSQL 9.2.3 on both computers, both of which run Win2008R2. I've setup streaming replication by following this guide: ...
4
votes
2answers
495 views

Is it ever a good idea to denormalize for integrity?

I'm using Postgres 9.2 to develop a quiz app, in which I present the user with a series of problems and record their answers. These problems can take a variety of forms - they might be multiple ...
0
votes
1answer
43 views

Storing no of players the last seven days in an online game

I want to plot the number of players, in the last seven days, of an MMORPG which haves 50~ servers. The system fetches the number of players in each server every 15 minutes and I'm not really sure how ...
4
votes
1answer
1k views

Postgres: count(*) vs count(id)

I saw in the documentation the difference between count(*) and count(pk). I had been using count(pk) (where pk is a SERIAL PRIMARY KEY) not knowing about the existence of count(*). My question is ...
1
vote
2answers
1k views

Dropping a group of schemas with similar name patterns

Consider a situation where one need to perform a bunch of essentially identical operations, with the only variable being the name of some object. In my case, I need to drop some schemas, all of the ...
3
votes
3answers
19k views

Getting SELECT to return a constant value even if zero rows match

Consider this select statement: SELECT *, 1 AS query_id FROM players WHERE username='foobar'; It returns the column query_id with value 1 along with a player's other columns. How would ...
-1
votes
1answer
248 views

Should I keep pg_xlog on the same disk as data if using disk snapshotting?

We're running on EBS volumes on EC2. We're interested in leveraging EBS snapshotting for backups. However, does this mean we'd need to ensure our pg_xlog is on the same EBS volume as our data? (I ...
12
votes
2answers
8k 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
1answer
10k views

Usage of COPY FROM STDIN in postgres

I just started using Postgres and I'm trying to create a sample db to understand its functions, looking around, I found some scripts in pgfoundry.org. I understand the commands, since I previously ...
0
votes
1answer
696 views

Cannot create PostgreSQL user

I'm using PostrgreSQL 9.1.9 on Ubuntu 13.04. Using the following StackOverflow question, I tried to create a user/role in postgressql: ...
3
votes
2answers
4k views

Creating a PostgreSQL SERIAL column using pgAdmin3

When I use pgAdmin3 to create a column of type serial, why does it instead create nextval('prices_id_seq'::regclass)? Should we keep this type defined by pgAdmin? Manually create the table with SQL ...
1
vote
2answers
217 views

“Rewinding” a Postgresql database

I have heard that Postgresql uses an append-only format for it's databases, and if this is true I should be able to 'rewind' the database to a previous point in time by removing the commits that came ...
4
votes
1answer
273 views

Is there better way to 'touch' a row than performing a dummy update?

I use the xmin system column to implement a form of optimistic locking, and sometimes need to 'touch' the row to bump xmin without actually updating the row. I currently just do a 'dummy' update: ...
1
vote
1answer
150 views

Postgresql socket not listening on the right one

I'm trying to get my postgresql to work. It is clearly running, according to: ps aux | grep postgres | grep -v grep I am getting - username 5781 0.0 0.0 2441364 524 ?? Ss ...
2
votes
1answer
1k views

PosgreSQL: setting high work_mem does not avoid disk merge

This is not quite my day with postgres. On my server machine with PosgreSQL 9.2.3 I have set work_mem to 4MB to avoid Sort Method: external merge Disk: 2072kB but it did not help: cwu=# vacuum ...
1
vote
2answers
2k views

Why PostreSQL 9.2 does not use index scan if it can?

My PosgreSQL planner (9.2) does not pick index and rather choose to do seq scan. Here is my table. The index I am talking about is name_left_prefix cwu=# \d web_city; ...