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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how to convert a master cluster to a slave cluster?

I am learning about PostgreSQL streaming replication and so far I have learned how to create a slave cluster using: pg_basebackup -x -R -D main -h host -p port I also have learned that I can ...
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9 views

PostgreSQL database connection time

how to check how much time PostgreSQL database takes for making connection?
3
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1answer
17 views

Use trigger to synchronize columns with fields in json column on insert or update

I'm a bit of a database/postgres beginner,so bear with me. If I have a table, something like this. CREATE TABLE testy ( id INTEGER REFERENCES other_table, name varchar(128) PRIMARY KEY, ...
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1answer
139 views

Array column vs another table when the relationship is quite small

The Data I am creating a table of cities and their zip codes for the United States. Some zip codes have a list of acceptable cities, as designated by the USPS. For example, the zip code 36613 is ...
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2answers
308 views

How to implement a dynamic string into a (prepared) sql statement?

I have some spatial datasets which are available in a open source metadata catalog software GeoNetwork and in a PostGIS database. The problem is that the student who created the database used ...
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5 views

How can I combine two event tables into a single timeline, in PostgreSQL?

Given two tables: CREATE TABLE foo (ts timestamp, foo text); CREATE TABLE bar (ts timestamp, bar text); I wish to write a query that returns values for ts, foo, and bar that represents a unified ...
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1answer
43 views

PostgreSQL doesn't log

I'm using ArchLinux and PostgreSQL 9.4.4 and have enabled the logging in the config file: $ sudo egrep -v "^[[:blank:]]*($|#|//|/\*| \*|\*/)" /var/lib/postgres/data/postgresql.conf max_connections = ...
2
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2answers
38 views

Locking issues under transaction on Postgres

I recently got a "Out of shared memory - You might need to increase max_locks_per_transaction" error. This is a long running process where I import a bunch of CSV files after proper processing. I ...
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3answers
148 views

Postgres is performing sequential scan instead of index scan

I have a table with about 10 million rows in it and an index on a date field. When I try and extract the unique values of the indexed field Postgres runs a sequential scan even though the result set ...
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1answer
482 views

Designing a High Score/Leaderboard table

I'm looking for input on how to design a highscore table for a game I'm creating. The database I'm using is postgres. That's not really something I can or want to change (unless there's very good ...
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1answer
25 views

Copying CSV file to temp table with dynamic number of columns?

I am wondering if there is a way to copy a csv file into a temp table where the number of columns is unknown in the csv file. The DB software I'm using is PgAdmin III. I figured out that if I do know ...
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1answer
33 views

Postgres 9.4+: JSONB instead of EAV

I'm figuring out a way to structure a new postgresql database, and I'm curious if I could use a JSONB column instead of the EAV model for storing properties of an entity. This seens like a flexible ...
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18 views

When does pg_dump not export CREATE EXTENSION?

I have a production database that I am trying to dump then load (in plain text format) locally. The problem is, the database being dumped uses the hstore extension in several tables, and contrary to ...
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16 views

Getting TEXT data from postgres throught linked server to MSSQL

I'm using MSSQL 2008 R2 with linked server to postgres 9.4. My problem is: when I select column with data type text it shows me only XXX first chars and adds (...) on the end. select description from ...
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22 views

PostgreSQL becomes very slow after heavy utilization

I have built a Python web application and I am hosting it in a 2GB RAM Debian Server. My application uses PostgeSQL 9.1 with PostGIS. One of my tasks involves importing data from big csv files. ...
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0answers
24 views

Is there a way to determine if a postgres function depends on a user-defined type?

I am writing a Ruby script to handle functions and user-defined types in Postgres. I want to make sure, that before a function is created in the database, if it uses a user-defined type, than this ...
2
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1answer
77 views

Subquery magic in PostgreSQL

I have a query: update product_product set (write_date, default_code) = (LOCALTIMESTAMP, 'update') where product_tmpl_id in ( select distinct product_tmpl_id from product_template ...
2
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1answer
168 views

Postgres query plans and tuning parameters

I have a query for which the explain plan indicates that the cost for using a seq scan is lower than the cost for using an index that I have set up. However the actual time for the query is 20 times ...
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2answers
596 views

Set random value from set

I need to put some random values into database, but I don't want to end up with completely randomized text (like 7hfg43d3). Instead I would like to randomly pick one of values supplied by myself.
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2answers
4k views

What is faster, one big query or many small queries?

I have been working for different companies, and I have noticed that some of them prefer to have views that will join a table with all its "relatives". But then on the application some times, we only ...
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2answers
177 views

How to speed up ORDER BY sorting when using GIN index in PostgreSQL?

I have a table like this: CREATE TABLE products ( id serial PRIMARY KEY, category_ids integer[], published boolean NOT NULL, score integer NOT NULL, title varchar NOT NULL); A product ...
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40 views

Connection refused when inserting

Description: Machine 1: Linux, PostgreSQL 9.3, on local, 10.12.10.123 Machine 2: Linux, PostgreSQL 9.3, on cloud, 104.10.124.123 Configuration (on both): + postgresql.conf : listen_addresses ="*" + ...
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2answers
54 views

Minimizing SELECT latency in PostgreSQL

I am evaluating Postgres 9.4 performance on a machine with Intel i7 quad-core 3.6 GHz CPU, 8 GB ram, and 7400 rpm HDD (no RAID) running Linux Mint. The DB schema has the following table: ...
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82 views

Leap second in Database system (Postgresql and SQL Server)

This night will be longer because of leap second: https://en.wikipedia.org/wiki/Leap_second My impact will be minimal in my case, I don't even know if I will recive some weird data like 20150630 ...
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1answer
152 views

Unsupported languages in Postgres Full text search

My web application supports 3 languages, English, Traditional Chinese, Vietnamese. I understand that Traditional Chinese and Vietnamese is not supported in Postgres' Full Text Search. If I were to go ...
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27 views

Column doesn't exist in PostgreSQL View [on hold]

I have the below situation but I don't get what is the problem with my code. I receive this error: column vx1 doesn't exist. vx1 double precision; vy1 double precision; vz1 double ...
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2answers
3k views

Query across multiple schemas, unknown until execution time

I have multiple schemas that I need to query across. The schemas are not known in advance, for example: U111 U222 U333 I need to select across these three schemas from a specific table in each of ...
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28 views

What order do foreign key constraints run in? Why does my foreign key not work after import?

I have two tables tags and tag_memberships in a PostgreSQL database. On the tag_memberships table, I have two constraints. The first is this: ALTER TABLE tag_memberships ADD CONSTRAINT ...
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2answers
56 views

Would like to know why this query is behaving this way?

I have an emp table, with schema and some initial values like below: emp_id | name | last_name | role_id --------+------+-----------+--------- 1 | hell | bell | 1 2 | well | ...
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2answers
124 views

Is unique index better than unique constraint when an index with an operator class is required

Postgres docs say: The use of indexes to enforce unique constraints could be considered an implementation detail that should not be accessed directly. One should, however, be aware that there's ...
2
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1answer
37 views

Can column uniqueness be commutative?

I have a table in a Postgres DB where col1 and col2 are foreign keys referring to the same column. I want only unique combinations of (col1, col2), i.e. if (1,2) is entered then (2,1) should be ...
11
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1answer
6k views

Index optimization with dates

I have a large table of objects (15M+ row) in PostgreSQL 9.0.8, for which I want to query for outdated field. I want to divide the query by millions, for scalability & concurrency purposes, and I ...
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1answer
176 views

Postgres automatic failover, multiple clients to multiple masters

I'm looking into providing a method of having multiple hot spare PostgreSQL instances to our website. The majority of implementations that I have found require a single point of failure with PgPool ...
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31 views

Database migration stops halfway through

I've had issues trying to use PostgreSQL so changed my application to use MYSQL. But, when I run rake db:migrate I get the following message before the migration stops: -- PostgreSQL database ...
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1answer
139 views

Why won't pg_basebackup output go to log?

I run a nightly pg_basebackup from a cron job (Postgres 9.3 on debian "wheezy"), but the backup has been failing. It actually creates output, but the .tar file is corrupt and won't extract. I went to ...
4
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1answer
373 views

Monitoring Amazon RDS with pgtop

I recently migrated a Postgres database to Amazon RDS and I am lacking a good live monitoring tool. I tried pgtop, but I can't get it to work on Amazon. I can see the header with the DB statistics ...
3
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1answer
171 views

PostgreSQL server problem in Windows XP

2014-10-01 09:22:49 IST LOG: database system was interrupted; last known up at 2014-09-30 18:30:24 IST 2014-10-01 09:22:49 IST FATAL: the database system is starting up 2014-10-01 09:22:49 IST LOG: ...
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1answer
32 views

Index on colum with data type citext not used

In PostgreSQL 9.4, with following schema: CREATE TABLE people ( id INTEGER PRIMARY KEY, name TEXT, junk CHAR(1000) ); INSERT INTO people(id, name) SELECT generate_series(1,100000), ...
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2answers
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+500

How to do incremental backup every hour in Postgres?

Trying to do an hourly incremental backup of a single Postgres server (Win7 64). I have the following setup in postgresql.conf: max_wal_senders = 2 wal_level = archive archive_mode = on ...
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2answers
951 views

Unnest multiple arrays into rows

I have been shown a great way to bulkinsert with this example: WITH p AS ( INSERT INTO parent_table (column_1) SELECT $1 RETURNING id) INSERT INTO child_table (parent_table_id, ...
29
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3answers
21k views

Idiomatic way to implement UPSERT in PostgreSQL

I've read about different UPSERT implementations in PostgreSQL, but all of these solutions are relatively old or relatively exotic (using writeable CTE, for example). And I'm just not a psql expert ...
0
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1answer
22 views

Kibana-like tool for PosgreSQL [closed]

I'm looking for a tool that could browse and visualize data from db like Kibana does. I'd prefer a native Posgres tool to any that transfers data from a db somewhere else. I know that rivers for ...
2
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1answer
23 views

Persistant inserts in a UDF even if the function aborts

I have a rather complicated UDF (moves around a bunch of tables as well as creates a bunch of new ones) where multiple aborts may occur. Before every operation I would like to record the time when an ...
4
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2answers
80 views

Avoid unique violation in atomic transaction

Is possible to create atomic transaction in PostgreSQL? Consider I have table category with these rows: id|name --|--------- 1 |'tablets' 2 |'phones' And column name has unique constraint. If I ...
2
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2answers
129 views

Tuning Postgres for Single connection use? Or is postgres wrong tool?

Any rules of thumb for work_mem, maintenance_work_mem, shared_buffer, etc. for a database that DOESN'T anticipate concurrent connections and that is doing lots of aggregate functions? I'm a social ...
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2answers
5k views

Disable all constraints and table checks while restoring a dump

I've obtained a dump of my PostgreSQL database with: pg_dump -U user-name -d db-name -f dumpfile which I then proceed to restore in another database with: psql X -U postgres -d db-name-b -f ...
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2answers
1k views

How to take pg_dump of a very large postgres database?

I have a production database server running Postgres 8.4 on Cent OS 6.5.The volume of data has increased recently and within few months database now has 18500 tables amounting to approx 350GB database ...
2
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1answer
119 views

Should database be denormalized if I need an index across multiple tables

I have a catalog of album and song names. The song has a foreign key to the album table. I expect queries like: SELECT * FROM song s JOIN album a ON a.id = s.album_id WHERE LOWER(CONCAT_WS(' ', ...
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0answers
19 views

Creating a unique index on a materialized view with no unique columns?

I am using Postgres 9.4. I have created a materialized view from one of my tables and I want to be able to refresh it concurrently. I know from the documentation that in order to do a concurrent ...
1
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1answer
18 views

Select Distinct on subset of columns, name different set of columns to return

I am using PostgreSQL and have two tables: Table_A colA | colB | colC | colD | colE | colF | colG | colH | colI | colJ Table_B colA | colB | colC | columnD | colE | columnF | colG | colH | colI | ...