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 ...

learn more… | top users | synonyms (1)

2
votes
1answer
412 views

Query takes hours

Up until now all queries in my PostgreSQL application were fast. During the last days, sometimes a query takes several hours. Index are healthy, because after dump, restore, vacuum -z, it is still the ...
2
votes
3answers
1k views

Change column type from varchar to text in all tables at once

I am using Postgres. I would like to change column type in all tables where column name is "description" from varchar(255) to text. If anyone knows that I would be very glad for your help.
2
votes
1answer
389 views

What is the difference between MySQL and PostgreSQL in terms of writing SQL queries? [closed]

Other than performance and security is there really any difference between MySQL and Postgres like SQL queries, built-in functions, procedures and so on? I'm asking this because I'm familiar with PHP ...
2
votes
1answer
611 views

Two-column foreign key constraint only when third column is NOT NULL

Given the following tables: CREATE TABLE verified_name ( id SERIAL PRIMARY KEY, name TEXT NOT NULL, email TEXT NOT NULL, UNIQUE (name, email) ); CREATE ...
2
votes
3answers
2k views

Postgres connection access denied on IPv6 address

Installed PostgreSQL 9.1 x64 on Windows, set up a listen address, but when connecting with pgAdmin I get the following error. Not sure why PostgreSQL is seeing my IPv6 address and not my regular IP ...
2
votes
3answers
10k 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 ...
2
votes
4answers
8k views

What GUI tools can be used for PostgreSQL in Mac OS X? [closed]

I have recently started using PostgreSQL with my rails app. I was looking for a SQL GUI to the PostgreSQL database (for Mac). Anything better than pgadmin3?
2
votes
2answers
125 views

Database Agnostic Conditional

I'm writing a Drupal module and I want it to be agnostic between PostgreSQL and MySQL. I have a field that gets its value from a conditional, and I originally wrote it as an IF(). Then I found out ...
2
votes
2answers
153 views

Official PostgreSQL Capitalization conventions [closed]

Is there an official PostreSQL convention regarding capitalization in DB, Table and field names? The examples on the official site suggest a lowercase and _ word separation, and I wonder whether this ...
2
votes
3answers
216 views

PostgreSQL 7.4 data corruption

We're dealing with the following situation (PG version is 7.4.30): somehow, a DB has gone missing from pg_database (psql \l listing doesn't show it anymore). More, while you can still \c to it, a \d ...
2
votes
2answers
729 views

PostgreSQL performance degradation over time on a write intensive db

I have observed a weird situation that over time the performance of a query (a combination of queries explained below) degrades, meaning at the start of testing (for a few minutes) the time of the ...
2
votes
2answers
354 views

Bug in PL/pgSQL function creation

I don't know if this question better suits here or in SO ... This is a script that I'd like to launch (the code of the function was copied from a question on SO): \c mydb create or replace function ...
2
votes
2answers
5k views

Most efficient way to add a serial column to a huge table

What's the fastest way to add a BIGSERIAL column to a huge table (~3 Bil. rows, ~ 174Gb)? EDIT: I want the column to be incremented values for existing rows (NOT NULL). I didn't set a fillfactor ...
2
votes
2answers
273 views

Attacks on Postgresql listening for requests on 'localhost'

I am using jboss server for my servlets and the postgresql as the database server, listening on port 5432 on localhost. My jboss server is bound to a public IP. I want to know that since my postgesql ...
2
votes
2answers
53 views

Call UPSERT function multiple times to different inputs

I have a function: merge_vehicles(vid, cid, vname, reg_no, name, name_1st) Can i call it multiple times on inputs like (2335, 55, '246BDH', '246BDH', '811', 1), (2336, 55, '038THX', '038THX', ...
2
votes
2answers
301 views

PostgreSQL maximize performance SSD

I will have a huge PostgreSQL 9.3 database with many tables with more than 100M entries per table. This database will be basically be read-only (once I fill all the necessary tables and build the ...
2
votes
2answers
106 views

Order of returned record with IN statement postgres

I know that the order of returned records is not guaranteed with the IN statement for Pstgres. For example if I do this: SELECT "users"."id" FROM "users" WHERE "users"."id" IN (13589, 16674, 13588) ...
2
votes
3answers
589 views

How to query efficiently from Postgres to select special words?

Let's say that I have a table called words with very many records. Columns are id and name. In the words table I have for example: 'systematic', 'سلام','gear','synthesis','mysterious', etc. NB: ...
2
votes
2answers
2k views

Insert values from a record variable into a table

I am developing a user-defined function that takes two arguments: create or replace function gesio( events_table_in regclass, events_table_out regclass) returns void as $$ ... $$ ...
2
votes
2answers
2k views

PostgreSQL difference between VACUUM FULL and CLUSTER

I have a table with 200 GB of size occupied by data and 180 GB of size by the 6 indexes on it. It is 30% bloated, so I want to reclaim unwanted space occupied by it. It is clustered on job_id_idx ...
2
votes
2answers
2k views

Recursive query using plpgsql

I'm trying to write a plpgsql function that recursively returns a set of columns from records in a tree structure. I have a data table and a table to link the data together: DATATABLE ----------- id ...
2
votes
2answers
2k views

How to execute a query from psql without waiting for the result?

My query (to create a new table from existing table) takes a very long time. So I've set up a remote database in my office - more RAM there. I can connect to my database from home as usual with psql. ...
2
votes
2answers
505 views

Is it a good idea to move high-volume and highly-accessed tables to a separate database?

Ours is a web-based application (built on multi-tenant architecture) running PostgreSQL v9.1.3. There are about 450 tables in our application, out of which 2-3 tables, specific to a module in the ...
2
votes
4answers
4k views

PostgreSQL import CSV File causes Syntax Error

I'm attempting to import a CSV file into a database via the "COPY" command; however, I get the (what seems common) error that I need to be a superuser and that I should use "\copy" instead. However, ...
2
votes
2answers
196 views

Postgresql: Two concurrent COPY FROM

I'm importing several gigantic csv files into a table - so I'm wondering what would happen if I ran COPY FROM jobs concurrently?
2
votes
2answers
1k views

Postgres - Create table with foreign key constraint too slow

I have a table called "Account" that is a heavily used table, has 17 columns and has upwards of 300,000 rows. I am trying to create a new table, "NewTable", that has a foreign key constraint to ...
2
votes
2answers
306 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 ...
2
votes
2answers
1k 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
votes
2answers
725 views

Role problem of PostgreSQL

I want to create a role named cp with some defined privileges, then we will create some other roles which will be granted with cp role. I know Oracle can do this job. For examle grant resources to ...
2
votes
2answers
433 views

Transferring concepts - users/groups/permissions of db objects from mysql to postgresql

This seemed like a better fit here than stackoverflow, so here goes: I've been using mysql for a while since on most of the cheap webhosts it is the provided database. However, now I've started ...
2
votes
2answers
272 views

Updating every cell of of a table?

I have a table with m columns and n rows. The ETL tools I was using wrote an empty ('') to every cell without a value and I would like them to be NULL instead. This got me thinking if it would be ...
2
votes
2answers
121 views

SQL order by query results in any arbitrary (but reproducible) manner

For testing purposes I need to get some data from a set of database tables in any arbitrary (but reproducible) order. The idea being that I can later compare two runs using a textual diff tool. Is ...
2
votes
6answers
68 views

Need separate columns that calculate percentage

I have the following table: NAME Alex Bob Bob Tim Alex Roger I need to produce the following: Name Count Percentage Alex 2 33% Bob 2 33% Roger 1 16.6% Tim 1 ...
2
votes
3answers
106 views

Constrain a postgres timestamp to “End of day”?

Given a table named bananas and a timestamp without time zone column named end_time and some psql clients have set timezone to 'UTC' and other psql clients have set timezone to 'US/Eastern' and the ...
2
votes
2answers
226 views

SELECT UNION from two views of the same table

(Sorry the the vague title, if anyone want to re-edit, be my guest!) I have these tables and views for a factory inventory module : +----------------------------+ +--------------------------+ | ...
2
votes
1answer
342 views

How to pass a parameter into a function

At the moment I have a view created, see it here in the answer. How can I create a function on that cross tab, so I can pass a date, and get data for the specific date? Also is it a good practice to ...
2
votes
2answers
158 views

Return several values from a PL/pgSQL procedure - to speed up the query

I have a non-forking game daemon written in Perl, which uses acync queries to write player stats into a PostgreSQL 9.3 database. But when I need to read something from database (like if a player is ...
2
votes
1answer
101 views

How to Substitute Variables in PostgreSQL

The given Oracle query inserts data into table by substituting variables. How I achieve the same in PostgreSQL? INSERT INTO control_threshold ( threshold_id, group_name, description, sql, ...
2
votes
2answers
198 views

How slow is slow in postgres?

I'm working with postgres for the first time. I have a lot of experience with small / medium size data analysis (i.e. things that fit in ram and can be analyzed in R, Stata, Matlab, etc.), but am now ...
2
votes
2answers
131 views

Most performant way to fetch last record

I have a Postgres table Prices with the columns price (Decimal) product_id (Int) Prices get updated regularly and I keep old prices in the table. For a given product, the last price in the table ...
2
votes
1answer
548 views

How to view the query of another session in pg_stat_activity without being super user?

I have a Postgresql 9.2 database. Two users are created on this database. When I perform the following query as superuser, I can see everything. select * from pg_stat_activity However, is it ...
2
votes
3answers
138 views

In what order does postgresql handle queries which have conflicting locks?

Let's say that I have a long running query SELECT and this query holds a AccessShareLock on a table. While this query is being processed a new query which needs a AccessExclusiveLock on the table ...
2
votes
4answers
233 views

psql, getting a list of databases to be parsed by a script

I want to use psql to list all of the databases on a Postgres server, to be parsed by a script. This command lists them: psql -l -A -t but the output shows an obvious issue: the records are ...
2
votes
2answers
246 views

how to create an incremental database copy in postgresql?

Virtual machine software like VirtualBox allow one to make incremental VM clones. That is data, once "touched" (opened writable), will be copied and stored in the incremental cache of the new clone. ...
2
votes
2answers
373 views

Optimize simple query using ORDER BY date and text

I have a query to a table in Postgres with an order based on a date field and a number field, this table has 1000000 records The data types of the table are: fcv_id = serial fcv_fecha_comprobante = ...
2
votes
1answer
2k views

How much time will a vacuum/autovacuum operation take?

I manage a big (some hundreds of gigs) database containing tables with various roles, some of them holding millions of records. Some tables only receive large number of inserts and deletes, some other ...
2
votes
2answers
479 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
votes
1answer
517 views

Use GIN to index bit strings

I'm trying to extend PostgreSQL to index bit strings up to 1000 bits. (These bit strings are created by quantization of high-dimensional vectors, so for each dimension up to 4 bits are assigned). ...
2
votes
2answers
119 views

Is there a way to avoid duplicating the definition of a foreign key?

I was wondering about this example CREATE TABLE cities ( city varchar(80) primary key, location point ); CREATE TABLE weather ( city varchar(80) references ...
2
votes
2answers
387 views

Combining two similar SQL queries

I'm using the following SQL query twice with different values of limit. In my case, 40 and 100, though it doesn't really matter. My question is - can I combine these two queries into one query? It ...