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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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
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1answer
838 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
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2answers
5k 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 ...
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2answers
230 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
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1answer
319 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: ...
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1answer
157 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
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1answer
2k 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 ...
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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; ...
3
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1answer
5k views

Error “column does not exist” in a SELECT with JOIN and GROUP BY query

I'm using PostgreSQL 9.1 with a Ruby on Rails application. I'm trying to list the last version of each "charge" (in my history table : hist_version_charges) belonging to the same project id ...
1
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2answers
316 views

Error installing pgcrypto extension [closed]

I want to install the pgcrypto extension on my postgresql installation on Windows. I found that I just have to call CREATE EXTENSION pgcrypto; but I've got an error : Syntax error on « CREATE » LINE ...
0
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2answers
273 views

Storing data in PostgreSQL: One table or two?

I've just started using PostgreSQL 9.2 and my data consists of product prices at various points in time, usually a different price every month. Question: Because every product can have different ...
1
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1answer
112 views

Does PostgreSQL work well as a workstation-based DBMS?

I've been considering PostgreSQL for an application I am writing in .NET WinForms, and the app is intended to be standalone with occasional sync-ing with a web service. I plan to use Sql Server for ...
2
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1answer
174 views

Mismatch between size computed from pg_buffercahce Vs shared_buffers in postgresql?

I have a rather naive question regarding the size of shared_buffers computed from pg_buffercache and the shared_buffers size mentioned in postgresql.conf. Based on my understanding pg_buffercache ...
1
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1answer
570 views

Postgres: Given some parent id's how can I SELECT X child records for each?

In Postgres, if I have : Parent Table id, name 1, Parent1 2, Parent2 ..... 5, Parent5 Child Table id, parent_id, name 1, 1, Child1 2, 1, Child2 ..... 6, 2, Child6 ..... 25, 5, Child25 so 5 ...
2
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2answers
745 views

Creating sequence for longer numeric values

I need to create a database model that includes a field to store 20 digit unique values. Which will be used by many clients over an API. The value must be 20 digit long, numeric and unique. Best ...
2
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2answers
474 views

PostgreSQL and default Schemas

Whenever I create a brand new database in PostgreSQL Maestro it creates the following list of default schemas: Now from my understanding Schemas are like folders for organization, etc. So the ...
2
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2answers
2k views

Get all partition names for a table

I want to list all the partitions created by dynamic triggers in PostgreSQL 9.1. I was able to generate a count of partitions using this related answer by Frank Heikens. I have a table foo with an ...
2
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1answer
704 views

How to get user-specific settings in PostgreSQL?

I have to collect some information of PostgreSQL roles. One piece of information is whether the role has different settings than 'usual', usual meaning here default values for only a few parameters ...
2
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2answers
155 views

Different queries result in big difference in performance

I have 2 similar functions, different way result in big diff in performance. The PostgreSQL version: 9.2.1. Function 1 create or replace function func_1() returns text as $$ declare v_i ...
1
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1answer
212 views

Equivalent of MRG_MYISAM in databases other than MySQL? [closed]

Does anyone know if other database have something equivalent to MRG_MYISAM (aka the MERGE table type/storage engine)? I know about fragmenting, but this is not quite the same AFAIK. We're using ...
4
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1answer
4k views

PostgreSQL: Cannot change directory to /root

I am trying to copy a table planet_osm_polygon from one database osm to another test. I su postgres and performed the pg_dump. Problem: However I'm getting the error could not change directory to ...
3
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0answers
314 views

How to count selectivity rows in PostgreSQL 8.2

I have problem with two queries on PostgreSQL v8.2. It seem like the optimizer chooses a wrong index: db=# explain select count(*), messagetype, alias from event where templateinfoid = 10 and ...
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1answer
3k views

Recovering a dropped table in PostgreSQL

I have : CREATE TABLE ketoan_vn.Customers ( CustomerId character varying(10) NOT NULL, CustomerName character varying(150), CONSTRAINT Customers_PK_CustomerID PRIMARY KEY (CustomerId) ); I ...
0
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1answer
111 views

PostgreSQL, How to keep only one schema?

I don't want some users be available to create schemas, and only use the public schema. I'd like to remove the permission of creating schemas, but I can't found anything on PotsgreSQL 9.1 ...
0
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1answer
47 views

look for missing datetime records in database

I have a python script that scrapes a webpage every minute of every day and saves the results in a postgres database. As I browse through the database, I've noticed there are minutes here and there ...
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2answers
4k views

PostgreSQL stored procedure to return rows or empty set

I have a stored procedure, which RETURNS SETOF ct_custom_type and inside I do RETURN QUERY EXECUTE 'some dynamic query' And I want to do this: If this 'dynamic query' returns >= 10 rows, I want to ...
0
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1answer
1k views

How to insert binary data into a PostgreSQL BYTEA column using libpqxx?

I'm a newbie at SQL, and even greener when it comes to using the PostgreSQL C++ API libpqxx. What I'd like to do is insert some binary data into a BYTEA column, but I find the Doxygen output is ...
0
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1answer
7k views

Using postgres with the command line without pgAdmin

I started working with PostgreSQL and till now I only had issues with it ( pgAdmin3 issues the most ) now I work a lot with MySQL and sometimes on the command line by just doing mysql -u ... -h ...
0
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1answer
2k views

postgres deadlock without explicit locking

I use PostgreSQL 9.2, and I do not use explicit locking anywhere, neither LOCK statement nor SELECT ... FOR UPDATE. However, recently I got ERROR: 40P01: deadlock detected. The query where deadlock ...
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2answers
868 views

In Postgresql, is it possible to change the maximum number of columns a table can have?

I'm tasked with keeping a postgres table in sync with a non-postgres table. The non-postgres table has more than 1600 columns. When I try to create the table in postgres, I get: ERROR: tables can ...
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1answer
2k views

Pass a table array as a parameter to an upsert function in postgresql

i have an UPSERT function which works well but i update and insert records in batches, can this function be modified so that i just pass all the records to this function as an array then it will ...
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2answers
736 views

PostgreSQL stored procedure which can return one of two custom rowtypes

I want to have one function, which can return two different types of rows according to given parameter. For example (simplified example) I have function like this: CREATE OR REPLACE FUNCTION ...
1
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1answer
289 views

Drop database from remote that has connected users

I have a "small" problem. There is a database server that contains a database where some test frontends are connected to. I want to update that database from a dump + some scripts to the most recent ...
0
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1answer
370 views

How is PostgreSQL extension feature compared to SQL Server extended and CLR stored procedures?

I am new to PostgreSQL. If I am not wrong, SQL Server has similar mechanism - extended stored procedures for adding new functionality to the base SQL Server functionality. CLR stored procedures could ...
5
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1answer
2k views

PostgreSQL concurrent increment of counter

I need to maintain a statistical table for a project, composed by a list of items and their usage (Think about something like a website in which you would like to count pageviews). Each time an item ...
1
vote
1answer
214 views

How to allow a user to create databases only with a certain prefix?

We're having a multi-user Linux server. I'd like to give each user the ability to create and manage databases at will, but to keep things sane, force them that each database name they create must ...
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2answers
3k views

PostgreSQL cannot start after replacing contents inside its Data folder

When recovering the Postgresql database from a hacked Ubuntu 12.04 server, I copied the data directory to another location, reinstalled the OS and PostgreSQL, stopped PostgreSQL service, removed the ...
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0answers
132 views

Identical Postgres index scan taking 5x longer on server [closed]

I have an intermediate table for managing a many-to-many relation between tables called Expert and Subject: Column | Type | Modifiers ...
43
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3answers
73k views

How do I list all schemas in PostgreSQL?

When using PostgreSQL v9.1, how do I list all of the schemas using SQL? I was expecting something along the lines of: SELECT something FROM pg_blah;
1
vote
1answer
126 views

Hiding variable input in psql

I am attempting to prompt for a username and password when running a database creation script, and I want to hide any text input for my password prompt. In Oracle's sqlplus, I can use HIDE at the end ...
4
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1answer
2k views

How to fine-tune Postgres for IO usage?

I have a Postgres database I am hosting in a quad core server with 8 GB of RAM. At any time, there can be 100 or so reads and writes occurring concurrently. I am experiencing high IO wait time. When ...
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4answers
6k views

How to change the data directory on Postgresql 9.1 on Ubuntu

I am having a problem changing the data directory on postgresql 9.1 on ubuntu 13.04: I first did a: sudo pg_dropcluster --stop 9.1 main and then attempted to create a new one in the desired path: ...
2
votes
1answer
1k views

Why does pgAdmin3 set OIDS=FALSE and owner to postgres by default?

Why does pgAdmin3 automatically set the table owner to postgres when its created and set OIDS=FALSE? I am new to PostgreSQL and want to know the rational behind this default behavior. -- Table: ...
3
votes
2answers
476 views

How to implement posts with “seen by” like facebook?

Inside a Facebook group there is a feature when every time see the group newsfeed it mark all posts as seen by me. And if I see a specific post inside a group thought a url ...
4
votes
1answer
517 views

Streaming Replication Failover - how to point second slave at new master?

I have a Postgres database HA cluster I've set up in a lab. I'm using PgPool-II to manage fail-over. For the cluster itself, I have three identical Postgres 9.2 servers set up like so: Server A - ...
2
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2answers
18k views

Use CASE to select columns in UPDATE query?

I can use CASE to choose which columns to display in a SELECT query (Postgres), like so: SELECT CASE WHEN val = 0 THEN column_x WHEN val = 1 THEN column_y ELSE 0 END AS ...
0
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1answer
245 views

Postgres sql dump import error

I'm facing a issue while importing the dump in my system, i'm getting the error as " Error: syntax error at or near "" LOCK TABLESDB_NAME` WRITE;" and exiting with "out of memory" We had ...
3
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1answer
1k views

In Postgres, How can I merge two tables?

I have a set of web services that all need updating with a new set of static data. I can't use a distributed transaction, but would like to be able to ask each service to rollback it's changes if I ...
8
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1answer
3k views

How to determine if there are [idle connections with] uncommitted transactions in PostgreSQL?

According to a comment on this question I asked about idle connections in PostgreSQL 9.2, some uncommitted transactions (possibly related to some of those idle connections) might cause some ...
5
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1answer
4k 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 ...