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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4
votes
1answer
2k 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 NOT NULL, ...
3
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1answer
5k views

PostgreSQL SELECT primary key as “serial” or “bigserial”

I've meshed together a way to determine what the data_type is as in the data_type you use in the syntax when creating a new table based off of the PostgreSQL wiki page. If there is something wrong ...
1258
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7answers
2.6m views

How do I list all databases and tables using psql?

I am trying to learn PostgreSQL administration and have started learning how to use the psql command line tool. When I log in with psql --username=postgres, how do I list all databases and tables? I ...
84
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6answers
11k views

Do stored procedures prevent SQL injection?

Is it true that stored procedures prevent SQL injection attacks against PostgreSQL databases? I did a little research and found out that SQL Server, Oracle and MySQL are not safe against SQL injection ...
39
votes
3answers
46k 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 ...
36
votes
3answers
164k views

Forgotten PostgreSQL Windows password

This morning I’ve been trying to connect the PostgreSQL database on my Windows 7 Professional desktop. The default value is ‘postgres’, but sure enough I forgot what password I used when I originally ...
61
votes
4answers
63k views

Can a single PostgreSQL query use multiple cores?

In recent versions of PostgreSQL (as of Dec 2013), can we share a query between two or more cores to get a performance boost? Or should we get faster cores?
42
votes
4answers
70k 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 ...
21
votes
4answers
8k 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 ...
16
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1answer
36k 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
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4answers
5k 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 ...
18
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3answers
13k 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
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2answers
44k 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
13k 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. ...
15
votes
3answers
9k 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 ...
13
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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 ...
9
votes
1answer
5k 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 || ')' ), ...
7
votes
2answers
7k 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 ...
12
votes
2answers
81k 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, ...
11
votes
2answers
26k 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 ...
8
votes
1answer
7k 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 (...
20
votes
2answers
12k views

Does Postgres preserve insertion order of records?

For example when I'm using query which returns record ids INSERT INTO projects(name) VALUES (name1), (name2), (name3) returning id; Which produce output: 1 2 3 Will this ids point to corresponding ...
8
votes
3answers
30k 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 ...
8
votes
3answers
35k views

Get rows with most recent date for each different item

Let's say this is the sample date coming from a join of 2 tables. Database is Postgres 9.6 id product_id invoice_id amount date 1 PROD1 INV01 2 01-01-2018 2 PROD2 ...
8
votes
1answer
3k 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
2k views

Finding the most commonly used non-stop words in a column

Simply put, I have a Postgres column containing ordinary prose and would like to determine the x most commonly used words ("word" being a group of characters delimited by a space, but not being stop ...
5
votes
2answers
4k 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 ...
24
votes
2answers
23k 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. ...
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
5k 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
5k 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
21k 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 $$ ... $$ ...
3
votes
2answers
11k 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 ); ...
11
votes
1answer
12k 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[] ...
7
votes
1answer
268 views

Why is PostgreSQL 9.5 not using my newest index for ORDER BY, even though it uses similar indices just fine?

(Follow up from this post: Why is my PostgreSQL expression index not being used when I ORDER BY in a subquery?) PostgreSQL 9.5. I can't divulge full details, but table has 22 columns and 5 indexes:...
7
votes
3answers
5k 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....
6
votes
2answers
2k 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 ...
4
votes
2answers
3k 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 ...
4
votes
1answer
763 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
1answer
538 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
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 ...
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 ...
14
votes
1answer
64k views

Postgres : Relation does not exist error

I used pg_restore to load my postgres db with a dump file. I connected to my db with my user : sudo -u arajguru psql dump select current_user; current_user -------------- arajguru Now I was able ...
7
votes
1answer
4k 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? ...
7
votes
3answers
868 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
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
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 ...
4
votes
1answer
2k 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.
3
votes
1answer
3k 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
2k 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 ...

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