Questions tagged [postgresql]

All versions of PostgreSQL. Add an additional version-specific tag like postgresql-11 if that context is important.

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Unable to reset the password of users in postgres

Evrytime i run, su - postgres it asks me for a password which I did not set. I simply installed the postgres. I have gone to the pg_hba.conf. # Database administrative login by Unix domain socket ...
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1answer
208 views

What database do most mobile start ups use? [closed]

mongodb? MySQL? PostgreSQL? If someone would add pluses and minus, let me know. Why I ask: I am a mobile startup. I need a database that supports spatial indexes. The spatial index must be able to ...
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1answer
2k views

postgres composite index design

In my rails application using the Postgres database, I have a table called tw_schedules which belongs to a scenarios table (one scenario to many tw_schedules). In addition to the scenario_id foreign ...
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1answer
637 views

Disk file effects of delete and vacuum

I have a very frequently updated table with 240 million rows (and growing). Every three hours 1.5 million rows are inserted and 1.5 million are deleted. When I moved the cluster to a SSD this bulk ...
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1answer
465 views

What is the “Data partitioned, Shared-Nothing, Parallel Database” solution for PostgreSQL ? [closed]

I was looking for a open source parallel database solution. It seems Postgres-XC is a viable solution. However, I don't need the replication. In this case, is there any better solution towards read ...
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1answer
1k views

Can't get past password lock on fresh install of postgreSQL

I feel really dumb writing this, I wanted to have a mess around with databases so I just installed postgreSQL (9.1) During the installation I am asked to provide a superuser password. I provide a ...
6
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2answers
3k views

Importing LARGE quantity of data into a PostgreSQL database

I am importing a large amount of data into a PostgreSQL server (across multiple databases on the server). When I last attempted to import the data, it effectively "crashed" my machine (Ubuntu 10.0.4),...
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1answer
195 views

Postgres Client - save table sorting

Is there a Postgres client (for Windows) that can save customized sorting when viewing tables? Obviously I could write and save a query for this, but perhaps there's a client that can do this for me. ...
3
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2answers
965 views

speeding up a deletion in postgresql

I came up with: drop table if exists idtemp; create temp table idtemp as select documentid from taskflag where taskid='coref' and state = 2 order by statechanged asc limit howmany; ...
2
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1answer
384 views

Initial recovery Postgres with backup in sync commit mode

I've got a master and a slave postgres 9.1.3 database. I would like to init the backup database for the first time. I did the following steps: Stopped master Copied all files to Slave Create recory....
3
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2answers
686 views

Migrating and normalizing data

We are rewriting a large Django application which uses a MySQL database, and the database schema needs to undergo major modifications. We're also porting the app to use PostgreSQL, for a couple of ...
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1answer
4k views

PostgreSQL Failover - What tools should I use?

Here is the scenario: There are two machines running CentOS 6.2 - machine0 and machine1 Both have PostgreSQL 9.1 installed. One of them should be active, as a master system and through asynchronous ...
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2answers
2k views

Creating a test database from Production database (different machines & servers)

I'd like to set up a test database on a separate server. Production database is MS SQL Server and the test server is a *nix box so I'd like to have the test server running either PostgreSQL or MySQL. ...
5
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1answer
14k views

how do I execute a void-returning procedure in pgsql 9.1?

If I execute the following in a file with the pgsql command, it complains that the procedure needs to be called with 'perform'. But when I try to use perform, it tells me that perform is not defined. ...
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1answer
444 views

using COPY command and wal_buffers

since COPY command runs inside a single transaction, if its WAL data doesn't fit into wal_buffers? for example if we are bulk importing from CSV file.
3
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1answer
1k views

What happens when checkpoint_segments reached?

I'm a bit confused with checkpoint_segments definition in PostgreSQL documentation. What happens when checkpoint_segments reached? The dirty pages in shared_buffers written to WAL. Then what is the ...
3
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1answer
798 views

PostgreSQL archive_command on Windows

What is the best method for WAL log transfer on Windows? I have two servers with Windows Server 2008, PostgreSQL 9.0 64bit. Servers do not have any shared SAN disk, they are on different hosts, ...
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2answers
7k views

Can I have one table be an “alias”, or “symlink”, to another?

I have two tables with the same structure, A and B. A certain application is written so that it always writes the same data to both tables. After a discussion with a colleague about the potential to ...
2
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0answers
53 views

Splitting a wide table [duplicate]

Possible Duplicate: Database Design: New Table versus New Columns I'm in the process of building a DB schema that contains information about something we call "blocks" (not very important to the ...
5
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1answer
840 views

Database as a service (DbaaS) over dimensions--performance, scalability, & reliability?

MySql Database as a service: Amazon Xeround Another eg. PostgreSQL Database-as-a-Service. You can get the list of similar products here. Does anyone have details on their performance, reliability, ...
2
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1answer
7k views

Error importing back a postgres db after dumping

I dumped my postgres db using pgAdmin in plain format because I wanted to search for some text on it. After doing the search, I decided to import the db back from the sql query window but I get this ...
5
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1answer
750 views

Upgrade Postgres without doing a pg_dumpall

I'm upgrading from postgres 8.4 to 9.0 and looking at the manual it looks like this is my only choice: pg_dumpall -p 5432 | psql -d postgres -p 6543 Which means I'll need to stop any writes to the ...
2
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1answer
438 views

Slow enumeration of schemas and tables in a largish database

We have a Postgresql 8.4.8 database server on a Debian system with a database that has 500+ schemas with roughly 300+ tables each. The schemas and tables are created by scripts, we cannot influence ...
2
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1answer
322 views

How do I resolve Postgresql error, “PL/Perl function must return reference to hash or array”?

The follow code used to work in Postgresql 8.4.11 with perl v5.10.1: =# select * From testfunction(); testfunction ------------------------ http://www.google.com/ However, after doing a ...
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2answers
3k views

How to convert SQL Server .MDF database to Mac OS PostgreSQL database on Mac OS X?

I need to import a SQL Server database which is in the .mdf format into a PostgreSQL database. My system is Mac OS X. How to do it in the easiest way?
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5answers
8k 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 ...
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1answer
1k views

How to know there is a maintenance job running on a postgresql database

I have a python script on postgresql database which is fetching records from sql server database and inserting it to postgresql DB after some filtering. this jobs is running by cron every two minutes. ...
6
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3answers
19k views

How to connect to remote PostgreSQL server

I wrote a web app, using java + spring+ PostgreSQL, which I have up and running. I have a tester for my system and I want him to be able to connect to my database directly to check the result of ...
1
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1answer
177 views

Postgres table size doubles are transaction completes

I have a table with 50 million rows and 40+ text columns. Size of the table is around 17GB. Inside a transaction, I add another integer column to the table and update all the rows with corresponding ...
21
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1answer
12k views

Why does NOT IN with a set containing NULL always return FALSE/NULL?

I had a query (for Postgres and Informix) with a NOT IN clause containing a subquery that in some cases returned NULL values, causing that clause (and the entire query) to fail to return anything. ...
1
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1answer
727 views

PostgreSQL vs MySQL benchmarks when a 2nd level cache is included

Has anyone been able to find any benchmarks comparing PostgreSQL and MySQL performance when they are used by a system through Hibernate (or another comparable ORM) and the 2nd level cache (backed by ...
14
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2answers
10k views

Index on primary key not used in simple join

I have the following table and index definitions: CREATE TABLE munkalap ( munkalap_id serial PRIMARY KEY, ... ); CREATE TABLE munkalap_lepes ( munkalap_lepes_id serial PRIMARY KEY, ...
3
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1answer
903 views

querying a linked PostgreSQL database in SQL Server 2008

We will be deploying an application with a Postgres back-end and need to provide report writing capabilities in SQL Server. I am exploring options for real-time or near real-time reporting in this ...
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3answers
37k views

What are the drawbacks with using UUID or GUID as a primary key?

I would like to build a distributed system. I need to store data in databases and it would be helpful to use an UUID or a GUID as a primary key on some tables. I assume it's a drawbacks with this ...
4
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2answers
4k views

Improving performance of nasty nested-view joins

I have a moderate-sized database spread out over a few tables, the rough architecture is: Input Data (Data ID, Session ID and a few fields of statistical importance) Input File (Data ID and a blob) ...
9
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1answer
7k views

Fast general method to calculate percentiles

I want to find n>1 percentiles of an unsorted column in PostgreSQL. For example the 20th, 40th, 60th, 80th and 100th percentile. An obvious solution is to count and sort the column and then do a ...
2
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1answer
16k views

How to export a table on postgresql command line

Anyone can do tell me how to do that? (I know maybe is a dumb question but I'm trying to learn how to use command line of postgresql) ~$ psql mybase psql (9.1.3) Type "help" for help. and then ...
2
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1answer
2k views

Dropping indexes doesn't seem to release space to the OS. Can it?

I'm running PostgreSQL 9.1. I have noticed really alarmingly bad indexes are taking up a lot of space on my server, e.g: evlampts=# SELECT pg_size_pretty(pg_relation_size('mcdata_2011_07')) AS ...
5
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1answer
2k views

Concurrency with Select-conditional Insert/Update/Delete - PostgreSQL

I have an intervals table which stores a start date and an end date for variables variable_id (four columns : id, start, end, variable_id). Clients compute new intervals for one variable and store ...
1
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2answers
930 views

pg_upgrade fails with an unspecified error

I’m running Postgres 9.1’s pg_ugrade to migrate from 9.0 to 9.1 on Windows x64. After editing the permissions to allow full trust, running the tool as the postgres user, and working around a bug ...
1
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1answer
1k views

slow index scan on postgresql 9.1

I have a view which is amazingly slow :) It joins two tables only, having a few simple WHERE conditions and one in a form of a subquery (see SubPlan1 below). The simplest condition is checked as an ...
2
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1answer
4k views

pg_restore: [archiver] unsupported version (1.11) in file header postgresql

My server is working on Ubuntu with PostgreSQL 8.4 and the development machine I'm using has Debian Lenny with PostgreSQL 8.3. My machine can't be upgraded to PostgreSQL 8.4 and I need to restore a ...
3
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4answers
5k views

migrating tables from Postgres to SQL Server 2008

(I fear what I wish to accomplish shall not be easy, but a lot of my googling around about it yielded rather dated results, so here it goes...) I have a Postgres 8.4.x database with over 100 tables. ...
0
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1answer
344 views

Update Postgres on server that already has version included with system

Mac OS X (Lion) Server includes Postgres (9.0.5) that it uses for some system utilities (Wiki server, caldav, etc.). I'm about to start using this server for some Rails applications and am wondering ...
2
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2answers
621 views

pg_relation_size does not show any difference after VACUUM ANALYZE

I wrote a script to backup a postgresql using COPY and then delete those records. I have used pg_relation_size before and after delete. pg_relation_size DELETE VACUUM ANALYZE pg_relation_size But ...
4
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2answers
2k views

psql won't list databases

I have a situation that I'm scratching my head over, but I'm new to postgresql, so I may be overlooking something obvious. I set up a testbed server and set access in pg_hba.conf: local all ...
2
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2answers
2k views

Request suggestion for a database between MySQL and Postgresql

We maintain a list of all the SAN Switch Ports that are either free or allocated to hosts. Currently, we enter the information on the company portal. But we need to move if off to a database because ...
0
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1answer
132 views

What DML commands can be allowed / limited on a reporting server?

I have a largish database (PostgreSQL 9.1) which I'm preparing to replicate using streaming replication. The 2nd server will be used for reporting and backup purposes. When building reports, it's ...
2
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1answer
338 views

Postgres synchronized backup - what's with the archive?

I am setting up a Postgres 9.1 master and a hot standby-server. I read the documentation but I'm not quite sure yet what I should do with my WAL files. Every commit is done on both servers before ...
2
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1answer
316 views

Working of window functions and idea window size for window function

I am not able to understand the concept of window functions. How exactly they work and what are the pros and cons of such technique? I have read that using limit and offset is slow but its still used....