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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ETL - Moving data from Postgres/Oracle to a TripleStore (RDF)

I'm looking for pointers on how to handle an ETL process that I have to implement for my organization. I know how to query SQL database but i'm not SQL DB specialist. I work more in the sphere of the ...
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44 views

Unique index on columns which are allowed to be NULL

I'm having a little problem right now, we use this table in our database: CREATE TABLE offer ( offer_id serial PRIMARY KEY , product_id int NOT NULL REFERENCES product , price_old ...
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2answers
46 views

Group by range of years

I've got a big table (~9M rows) and want to group the rows on a field containing the year. So far that's pretty easy: // greatly simplified: SELECT count(*), year FROM dataset GROUP BY year ORDER BY ...
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2answers
148 views

Managing CTE execution order under uncertainty

I am writing a large, multi-step CTE for performance reasons. In one query, data must be moved from one table to another, but the quantity of rows moved is uncertain and could be zero. In a ...
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2answers
33 views

Get all (non repeated) distribuidores with their paises given a producto_solicitud

I have this schema: And as title says I need to get all records from fabricante_distribuidor by given producto_solicitud.id value. I'm doing in this way: SELECT ...
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1answer
92 views

Prepared statement overhead

I am using libpqxx to communicate with a PostgreSQL 9.3 server. For multiple table inserts, if they are split into individual prepared statements, they cost approximately 2ms each. If they are all ...
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1answer
28 views

Initialize, Start Server and Create Database in Single Script

I am writing a provision script for a dev environment with the following: sudo su - postgres <<EOF cd ~/data pg_ctl -D . initdb pg_ctl -D . -l run.log start createdb mydb pg_ctl -D . stop EOF ...
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1answer
32 views

What are the side-effects of disabling nested loops in postgres?

A query of multiple joins spends a lot of time on nested loops. I disabled the nested loops and the query ran much faster. However, I have been told that nested loops might give me wrong results by ...
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2answers
35 views

How can I determine if a table exists in the current search_path with PLPGSQL?

I'm writing a setup script for an application that's an addon for another application, so I want to check if the tables for the other application exist. If not, I want to give the user a useful ...
5
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1answer
71 views

Sort by number of related rows in referencing table

Let there be two tables: Users id [pk] | name --------+--------- 1 | Alice 2 | Bob 3 | Charlie 4 | Dan Emails id | user_id | email ----+---------+------- 1 | 1 ...
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15 views

How to do a pgdump with strings encoded?

When I perform a dump with pg_dump tool, with a "flat" sql format, pg_dump create a regular sql file but the restoration with pg_restore fails because the strings are not escaped. For example, single ...
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1answer
53 views

Migrate SQL Server binary datadump to postgresql

I just got a very big dataset (+/-55GB) in a binary SQL Server format. Is there an easy way to import this file into a Postgresql Server? I found some converter-programs, but they 'only' convert ...
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1answer
51 views

What is the etymology of the hstore datatype in postgres?

Where did the datatype get its name? Hash store?
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2answers
63 views

Add function parameter to SQL query WHERE clause

I have a web application in java and it uses a query. I don't want to write the query into Java, so I made a function: CREATE OR REPLACE FUNCTION testFunc(inputs text) RETURNS TABLE(...) AS $$ ...
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0answers
36 views

Translate psql meta-command to SQL

How can I translate a psql meta-command (like \dt or \ds) to the equivalent SQL query? I found some of the translations here. But it would be nice to have a command to do it automatically.
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37 views

Getting wrong results from fulltext search in PostgreSQL

This is the query which I am running. The keyword "exhausted" is present only in one of the rows but I am getting all 3 rows. How to avoid the rows where the keyword is not present? DDL: CREATE ...
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1answer
22 views

create insertion rule on view returning id

I have a table private.products and a view public.products representing that table. And I want to create entries in private.products while inserting into view, it all works right, except that I also ...
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1answer
30 views

Can I use `on delete set null` on a compound foreign key which contains a primary key column?

The docs say: Restricting and cascading deletes are the two most common options. RESTRICT prevents deletion of a referenced row. NO ACTION means that if any referencing rows still exist when the ...
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1answer
42 views

How to update values from bytea to varchar in Greenplum?

I need to convert hexa to values and need to update the values in a varchar field, I have tried: select pg_catalog.decode(column,'hex') The above code converted hexa to values but when I try to ...
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1answer
42 views

Dropped an index and recreated it in PostgreSQL 9.2, not used anymore

I have a table with 15M rows, with two indexes; one of them is a very simple BTREE on a string column. While trying to optimize some queries, I created a new partial index on the same column. Using ...
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1answer
19 views

Optimizing for Modulo Queries

I have a use case where I want to be able to query tens of thousands of records for the modulo of a certain field value with another number, i.e. queries like SELECT * FROM EVENTS WHERE MOD(OFFSET)=5 ...
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19 views

hstore type does not exist with hstore installed postgresql

I recently had to copy over a databases structure from one database to another with the command pg_dump -c -S database_name > pg_dump_date.sql I then ran the dump file on the new database with ...
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1answer
47 views

Slow Postgres updates if OTHER columns are indexed?

Certain updates take far too long on large Postgres tables. Given these conditions: only one column is being updated, and it is non-indexed the column already has data in it for every row due to a ...
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1answer
13 views

Adding hstore entries to an uninitialized column

I got bitten by this 'feature' recently. If your hstore column is uninitialized and you start adding entries to it, they are all silently swallowed without error. Is this expected? create table ...
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0answers
49 views

How to make pg_dump skip extension?

This is on 9.3 but I can remember simillar things happening since 7.x. So I create database and install plpgsql extension into it. Later on I create a pg_dump and before restoring it into databse I ...
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1answer
55 views

Counting repeated occurences for a group of fields

I am trying to count the continuous repeated value for a field in order to obtain the maximum repeated occurrences for each person in the table. eg: Time person Result 08:12:36 ...
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57 views

How to Insert records from remote database to local database using dblink in postgresql 9.3

I have a scenario like i have a two DB, one resides in remote server and other resides local. Now i have to fetch the records from remote DB when new records are inserted on tables (in remote DB) and ...
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0answers
64 views

Why is the CTE much worse than inline subqueries

Im trying to better understand how the query planner work in postgresql. I have this query: select id from users where id <> 2 and gender = (select gender from users where id = 2) ...
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2answers
48 views

Alter table statement waiting (for hours, on dev machine), but no locks shown

I have been trying to issue a simple: ALTER TABLE tablename ADD COLUMN id_col character varying (30) type statement on a Postgres 9.1.13 build on Debian. The application is still in private beta, so ...
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39 views

Querying really slow Postgres

I have multiple tables on Postgres wit GIS and when I query SELECT * FROM rxmsg JOIN Vehicles ON rxmsg.vid=Vehicles.vid JOIN stops on ST_DWithin(rxmsg.point, stops.point,1000) JOIN drivers ON ...
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0answers
25 views

Postgres drop type XX000 “cache lookup failed for type”

I'm currently working on a PostgreSQL 9.2.x Database with a lots of Clients, and tables and functions. We deploy code constantly and sometimes it is necessary to even drop a type or a function due ...
2
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1answer
26 views

Is it safe to use set-returning sql functions instead of security-barrier views?

Since 9.2, it's been possible to use the security_barrier attribute to guard against maliciously-chosen functions and operators accessing data 'hidden' behind filters in views (full info in the ...
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28 views

Postgresql service run failure

Trying to setup replication through the wal shipping using Postgresql 9.3 x64. Used this instruction from youtube. The problem is - the slave postgresql service won't run. This is what in logs ...
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30 views

How to copy remote database to local cluster using pgAdmin over SSH tunneling with Postgres 9.x?

I have successfully gotten pgAdmin on my development machine to do ssh tunneling over the internet to my production server. I can see the remote database and browse its tables and such. ➥ How to suck ...
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1answer
28 views

Moving Local PostgreSQL 8.4.20 Database to Amazon EC2 or RDS

I'm running PostgresSQL 8.4.20 on a local server and plan to migrate the data to either Amazon EC2 or RDS. I have working knowledge of databases and need advice from experts. I've been researching ...
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13 views

Getting PAM-compatible password hashes from pgcrypto

I want to keep user records in Postgres database and faced one issue which block me. It is password encryption. For example, this is correcetly encrypted password 12345 via default Ubuntu crypt ...
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1answer
81 views

Slow max, min query in Postgresql View

I have a view and it's a left join between two tables (table_a has hundreds of millions of rows, table_b has ~2 millions). The query SELECT MIN("id") AS "min_id",MAX("id") AS "max_id" FROM "the_view" ...
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0answers
38 views

PostgreSQL Idle Session in Transactions with RELEASE_EXEC_SVP queries and lock

I am having a problem with having idle sessions in transactions. In pgAdmin Server Status, it is showing "RELEASE_EXEC_SVP_XXXXXX" (XXXXXX data are varied) as its query and it's locks also contain a ...
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1answer
41 views

How do you truncate a `date` (not `timestamptz`) to month?

Postgres has date_trunc which operates on timestamp or interval, and: Values of type date and time are cast automatically to timestamp or interval, respectively. In other words we can use ...
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2answers
69 views

How to calculate the cumulative difference between rows in Postgres?

I am in need of calculating the difference from the cumulative values for the previous day in Postgres based on session_id. Example as mentioned below: Date session_id upload_usage ...
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0answers
32 views

Is there a parser for Postgres' auto_explain to make it easier to read and understand?

We have a number of Postgres Functions that each call a number of other Postgres Functions. If you simply EXPLAIN ANALYSE a call like SELECT parent_function(), the output is minimal, since it doesn't ...
1
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1answer
58 views

How to remove object from json array?

My table: CREATE TABLE items ( id BIGINT PRIMARY KEY NOT NULL, name VARCHAR, images json ); images format: [ { "id": "owner", "full": "<url>", "thumb": ...
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1answer
27 views

Database storage limit for open source PostgresSQL

I just started using PostgresSQL. When I installed SQL Server Express years back, you typically had a database storage limit if you didn't install the full version. I think I remember it being 4GB, ...
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1answer
46 views

PostgreSQL - retrieving max primary key column to insert a new row - any alternatives?

We are using a software that needs to request the max primary key column value to add a new row into the table that was requested. I know that there are some alternatives like: Sequences, and GUIDs ...
0
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1answer
32 views

“explain analyze” cannot get detailed analyzed results for queries in a plpgsql function

I am using postgresql 9.3 I have a function (Pl/PgSQL) created with serveral complex queries inside. For example, create function f1() return integer as $$ declare event tablename%ROWTYPE; .... .... ...
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24 views

Slow query on large table after new column is added

I have a table with more than 30 million records, and I recently added a new column with type text. ALTER TABLE database.b ADD COLUMN x TEXT; CREATE INDEX CONCURRENTLY idx_x on database.b(a, x); ...
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1answer
82 views

Connect to PostgreSQL via a ssh tunnel using Cygwin

I would like to connect to a Postgres server installed on a remote server using an ssh tunnel. I have Windows so I use cygwin for SSH. I do the following on cygwin: # Create the tunnel ssh -f ...
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3answers
120 views

Return total number of rows and selected (aggregated) data

I have a function which is selecting some data from a table. I would like to return the selected data and the total number of rows in that table. How can I do that or how can I get the same result in ...
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2answers
68 views

postgres function extract from date returns double precision value

Why does postgres function extracting from date return double precision value? Only reason I could imagine is, there are some locales using calendars (those not Gregorian calendars and supported by ...
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28 views

migrate standalone postgresql database cluster to high availability cluster

We have tested one setup of postgres HA with repmgr and pgpool. It is working fine and now we have to migrate our existing database to the HA setup. We have two approaches, Make the HA master as ...