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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35
votes
4answers
54k views

Getting last modification date of a PostgreSQL database table

I'm trying to get when my table was modified by checking its file modification date as it is described in this answer. But the result is not always correct. The file modification date updates in ...
20
votes
4answers
7k views

Combining separate ranges into largest possible contiguous ranges

I'm trying to combine multiple date ranges (my load is about max 500, most cases 10) that may or may not overlap into the largest possible contiguous date ranges. For example: Data: CREATE TABLE ...
14
votes
1answer
32k views

How to use aes-encryption in PostgreSQL?

I tried aes-encryption by using following statement: SELECT encrypt('test', 'key', 'aes'); which worked, but I am not able to decrypt the value. I inserted it in a field of datatype bytea but I'm ...
18
votes
3answers
11k views

Get WAL files from AWS RDS PostgreSQL instance

We have a Postgres RDS instance on Amazon Web Services. We have automatic backups enabled, and we take snapshots on a daily basis. We would like to generate a local 'up-to-date' backup of the RDS ...
25
votes
1answer
17k views

Indexes: integer vs string performance if the number of nodes is the same

I am developing an application in Ruby on Rails with the PostgreSQL (9.4) database. For my use case, columns in tables will be looked up very frequently, as the whole point of the application is ...
15
votes
3answers
8k views

PostgreSQL vs. MySQL: spatial feature comparison

We are the in the process of building out a web application that has a spatial data component. In the beginning our spatial data comparisons will take a given point and return matched overlapping ...
15
votes
4answers
4k views

How do I generate a pivoted CROSS JOIN where the resulting table definition is unknown?

Given two tables with an undefined row count with a name and value, how would I display a pivoted CROSS JOIN of a function over their values. CREATE TEMP TABLE foo AS SELECT x::text AS name, x::int ...
13
votes
1answer
2k views

Why is a new user able to create tables in PostgreSQL?

I followed two tutorials to create a DB with: a fully privileged user link a read-only user link I then got a tip from CJ Estel's tutorial stating that "you may have inherited the ability to create ...
22
votes
2answers
37k views

How to set Postgresql database to see date as “MDY” permanently

How can I set my database to see the 'date' as "MDY" without running: SET datestyle = "ISO, MDY"; every-time I'm trying to access it? I'm using Postgresql version 9.1, Ubuntu 12.04. My system locale,...
21
votes
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. ...
7
votes
1answer
6k views

How to create an index on an integer json property in postgres

I can't figure out for the life of me how to create an index on a property of my json column which is an integer. I tried it this way (and also dozens of others) CREATE INDEX user_reputation_idx ON ...
7
votes
1answer
6k views

Best index for similarity function

So I have this table with 6.2 millions records and I have to perform search queries with similarity for one for the column. The queries can be: SELECT "lca_test".* FROM "lca_test" WHERE (...
7
votes
1answer
4k views

Order by distance

If I have a query returning nearby cafes: SELECT * FROM cafes c WHERE ( ST_DWithin( ST_GeographyFromText( 'SRID=4326;POINT(' || c.longitude || ' ' || c.latitude || ')' ), ...
36
votes
2answers
17k views

PostgreSQL EXCLUDE USING error: Data type integer has no default operator class

In PostgreSQL 9.2.3 I am trying to create this simplified table: CREATE TABLE test ( user_id INTEGER, startend TSTZRANGE, EXCLUDE USING gist (user_id WITH =, startend WITH &&) ); ...
10
votes
1answer
17k views

PostgreSQL: Pass table as argument in function

I am discovering TYPE in PostgreSQL. I have a TABLE TYPE that some table must respect (interface). For example: CREATE TYPE dataset AS( ChannelId INTEGER ,GranulityIdIn INTEGER ,GranulityId ...
9
votes
1answer
57k views

Permission denied for relation <table>

I have ran the following SQL in psql: CREATE USER bspu LOGIN; CREATE DATABASE bsp OWNER bspu; GRANT ALL PRIVILEGES ON DATABASE bsp TO bspu; \c bsp CREATE TABLE users ( id SERIAL PRIMARY KEY, ...
7
votes
1answer
2k views

2 B-tree indices OR 1 GiST index on tsrange — which will perform better?

I have a table which is storing reservation data using the columns starts_at & ends_at Whenever I'm querying the table to find overlapping reservations, I have an option of using one of the ...
7
votes
3answers
27k views

GROUP BY one column, while sorting by another in PostgreSQL

How can I GROUP BY one column, while sorting only by another. I'm trying to do the following: SELECT dbId,retreivalTime FROM FileItems WHERE sourceSite='something' GROUP BY seriesName ...
10
votes
2answers
2k views

What fillfactor for caching table?

I have heavily updated / accessed table where I store serialized java objects. They are in the table for 2-3 hours (also are being updated during that period) and then removed. Size of table is around ...
4
votes
2answers
2k views

Create a trigger on all the last_modified columns in PostgreSQL

In PostgreSQL 9.5, I have tables with columns in the form prefix_last_modified timestamp without time zone NOT NULL DEFAULT (clock_timestamp() AT TIME ZONE 'UTC') I was looking for a way to set ...
3
votes
2answers
4k views

Assign to NEW by key in a Postgres trigger

In the trigger body, how can I assign a value to NEW by it's field name? That's what I want to do: some_key = "some_column"; NEW[some_key] = 5;
3
votes
2answers
4k views

Why can a new user select from any table?

When I create a user in Postgres, create user test with password 'test'; The user ends up being able to connect to every database in the instance. The user can also select from any table: # psql -...
3
votes
2answers
9k views

Understanding multiple table join with aggregation

I have a basic question on how JOIN works on multiple tables. I want to count occurrences of Foreign Key in link1 & link2 CREATE TABLE main ( id SERIAL PRIMARY KEY, name text NOT NULL ); ...
3
votes
2answers
18k 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
1answer
5k views

Solving “Gaps and Islands” with row_number() and dense_rank()?

How does one solve the islands part of gaps-and-islands with dense_rank() and row_number(). I've seen this now a few times and I'm wondering if someone could explain it, Let's use something like this ...
17
votes
2answers
19k views

Can I select data inserted in the same uncommited transaction?

Maybe this is a dumb beginner question, but I cannot find an answer anywhere. Everywhere I read about the Transaction Isolation which solves the visibility of data within the concurrent transactions. ...
11
votes
1answer
11k views

How do I get the aggregate of a window function in Postgres?

I have a table containing a two columns of permutations/combinations of integer arrays, and a third column containing a value, like so: CREATE TABLE foo ( perm integer[] NOT NULL, combo integer[] ...
8
votes
2answers
12k views

How do I remove duplicate records in a join table in PostgreSQL?

I have a table that has a schema like this: create_table "questions_tags", :id => false, :force => true do |t| t.integer "question_id" t.integer "tag_id" end ...
6
votes
2answers
1k views

Improve performance for order by with columns from many tables

Using PostgreSQL 8.4, I'm trying to consult two tables with 1 million records using order by with indexed columns of the two tables, and I'm losing performance (with 1 column takes 30 ms and with two ...
6
votes
3answers
4k views

How to prevent a PostgreSQL trigger from being fired by another trigger?

I have 2 triggers on one table; one works for INSERTs : CREATE TRIGGER "get_user_name" AFTER INSERT ON "field_data" FOR EACH ROW EXECUTE PROCEDURE "add_info"(); This updates some values in the table....
4
votes
1answer
438 views

Why does PostgreSQL interpret numeric UTC offset as POSIX and not ISO-8601?

Setting time zone as numeric offset (without abbrev, thus IMO not in POSIX format) is still interpreted by PostgreSQL as POSIX format: SET TIME ZONE '+02:00'; At least I assume, because checking the ...
4
votes
3answers
3k views

How to reclaim disk space after delete without rebuilding table?

Our PostgreSQL 9.0 Windows production server is running low on space. In our 100GB database, we have a large table containing TOASTed binary data. We have deleted some rows and need to return the ...
4
votes
2answers
2k views

In PostgreSQL, what is the difference between a “Stored Procedure” and other types of functions?

I understand the distinction between: Scalar functions Set-Returning-Functions (SRF)s Internal functions Window functions Aggregate functions of all sorts User-Implemented functions (which in ...
4
votes
1answer
408 views

Persistent 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
votes
2answers
2k views

PostgreSQL unexplained table bloat

I have a table in a Postgres 8.2.15 database. The table bloated to almost 25GB but after running vacuum full and cluster the table size was dramatically smaller, well under 1GB. A few weeks later ...
3
votes
3answers
361 views

Does a query with a primary key and foreign keys run faster than a query with just primary keys?

SELECT something FROM table WHERE primary_key = ? vs. SELECT something FROM table WHERE primary_key = ? AND other_key = ? Say that this is a scenario where the inclusion of other_key does NOT ...
3
votes
1answer
1k views

Query optimization or missing indexes?

I have this query to aggregate some data from t2 into t1. This is done to optimize the application I am working on so that there are less queries to the database. I chose the below approach to make ...
7
votes
3answers
845 views

Issue with composite type in an UPSERT function

I have a function in PostgreSQL 9.1 called fun_test. It has a composite type as input parameter and I keep getting a casting error when I call it. CREATE OR REPLACE FUNCTION netcen.fun_test(myobj ...
6
votes
1answer
3k views

Creating UUID extension as the non super privileged user

I need to load the uuid extension on my database, which is being created in runtime. The user that created the db is not superuser, she only has the "CREATEDB" permissions. Is there a way to do this? ...
6
votes
1answer
1k views

Inconsistent statistics on jsonb column with btree index

I noticed that the performance of a query involving a jsonb column varied significantly between VACUUM ANALYZE runs while testing it. I get completely different execution plans seemingly randomly ...
4
votes
1answer
1k views

Understanding psql prompts

What is the difference between postgres=# and postgres-#? I tried googling it and looking on the official site but could not get a hit for the symbols.
4
votes
1answer
8k views

Permission for sequence in another schema

Postgres 9.3 Debian 7.0 I created a specific schema for a specific user and created a view in this schema for this user, so it's the only table he knows that exists. The problem is that this same ...
3
votes
1answer
2k views

Index on column 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), md5(...
2
votes
1answer
1k views

Inserting into related tables

I have a database setup with the following schema: CREATE TABLE siteInfo ( siteID SERIAL NOT NULL, siteName TEXT NOT NULL, siteHost TEXT ...
2
votes
1answer
1k views

Percentile rank that takes sorted argument (or same functionality) in PostgreSQL 9.3.5

How do I calculate the percentile of the nth element in a field relative to the ones previous to it in a time series for each subset (partition) of my data? For example, this is exactly what I want ...
1
vote
2answers
225 views

What administration utilities does Ubuntu and Debian package with PostgreSQL?

I see that there are a lot of tools authored by Ubuntu and Debian for PostgreSQL? Does any one have a list of them, or the build-differences?
1
vote
2answers
937 views

Complex view becomes slow when adding ORDER BY in outer query with small LIMIT [closed]

I have a pretty large query in a view (let's call it a_sql), that is really fast unless I use ORDER BY in an outer SELECT with a small LIMIT: SELECT customs.id AS custom_id, customs.custom_name AS ...
64
votes
3answers
126k views

How to use psql with no password prompt?

I wrote a script to REINDEX indexes in a database. Here is one of them: echo -e "\nreindex for unq_vbvdata_vehicle started at: `date "+%F %T"`" >> ${LOG_FILE} psql -U ${USERNAME} -h ${HOSTNAME} ...
42
votes
1answer
62k views

How to get a working and complete PostgreSQL DB backup and test

I was hoping I could get a clear answer on how to ensure taking a full Postgres backup just like you would get with MS SQL Server, and then take care of orphaned users. From what I've read, and it ...
32
votes
5answers
45k views

Export Postgres table as json

Is there a way to export postgres table data as json to a file? I need the output to be line by line, like: {'id':1,'name':'David'} {'id':2,'name':'James'} ... EDIT: postgres version: 9.3.4