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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3
votes
1answer
24 views

Select a count with some conditions

Using Postgres 9.4, I have a table page_views which has a page column. I'd like to select all the distinct pages and have a count before them and sort them descending. I'd also like to have a minimum ...
1
vote
1answer
12 views

Postgres: Is migrating old records to separate table and creating new aggregated records a good strategy to improve search speed?

I have a table with 1M+ records. New records are created and updated each day each time an event occurs for each type of event (which there are many). I frequently need to find sums across many ...
1
vote
1answer
10 views

RETURN TABLE is converted to RETURN SETOF int in Postgres function

I am trying to create a function that returns multiple rows in a single column named identifier, but the column keeps getting automatically renamed. I am executing the following in pgAdmin III: ...
2
votes
0answers
21 views

How to do Statistics in Partial Indexes of PostgreSQL efficiently?

This answer motivated think again my following tables but I am still uncertain how to store statistic data for quick selection. I think it is well done with partial indexes because only a subset of ...
4
votes
3answers
32 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, ...
1
vote
2answers
21 views

Postgresql: Insert trigger function fails on partial insert statement

We have some big tables in our database and the boss thought that partitioning would be a good improvement to our system. I was charged to investigate it and develop all the needed scripts in a test ...
6
votes
1answer
35 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 ...
5
votes
1answer
31 views

Naming conflict between function parameter and result of JOIN with USING clause

Given this setup in current Postgres 9.4 (from this related question): CREATE TABLE foo (ts, foo) AS VALUES (1, 'A') -- int, text , (7, 'B'); CREATE TABLE bar (ts, bar) AS VALUES (3, 'C') ...
3
votes
1answer
35 views

How to get the difference in days between 2 timestamps in PostgreSQL

I have a table named accounts. I am interested in retrieving those accounts whose status has not been updated since more than 10 days. I thought about this query and it seemed to work but I am not ...
2
votes
1answer
32 views

can't connect to remote postgresql database

I'm trying to connect to a remote psql database. Before I added the pg_hba.conf entry with the client's IP address, I was getting an error message : xdev@xdevbox:~$ psql -U postgres testdb -h ...
-1
votes
3answers
74 views

psql: could not connect to server and socket /var/run/postgresql/.s.PGSQL.5432

I have installed postgresql 9.4 and I removed postgresql 9.3 from my computer. Now when I try to run: foo@bar:~$ psql I get the error psql: could not connect to server: No such file or directory ...
2
votes
1answer
57 views

PostgreSQL force upper case for all data

Is there a way to force all text data to uppercase without recurring to writing a function for every table or doing it client side?
2
votes
1answer
22 views

Find substrings within between 2 string fragments

I am trying to populate a view in PostGIS in Postgres 9.0 and in this view I want it to contain a substring based on 2 string positions. See below for my code. CREATE OR REPLACE VIEW vw_actions AS ...
0
votes
0answers
22 views

Automatic failover mechanism for PostgreSQL

I need to have a automated failover setup in my production environment for postgres DB. Though I have explored various articles/blogs to achieve the same, I am not fully convinced on the methods ...
1
vote
1answer
81 views

Does PostgreSQL support online schema modification (DDL)?

Recent versions of MySQL (using InnoDB) support many alter table queries without exclusive locking the table. Does PostgreSQL support this to any level? That is, can I add/drop columns from a table ...
-2
votes
1answer
24 views

Like operator in postgresql [on hold]

how to check the reverse of the original word using like operator? For Eg: victoria state------state victoria This is the query i tried: SELECT DISTINCT ON (t1.name) ...
0
votes
1answer
3k views

Postgres FATAL: could not open relation mapping file

I installed postgress.app on mac os when I try to connect to console : psql -h localhost I got this problem . psql -h localhost psql: FATAL: could not open relation mapping file ...
3
votes
1answer
100 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 ...
4
votes
1answer
41 views

Truncate parent table but not children

I have a table in PostgreSQL 9.4 that I partitioned so that all inserts to the parent actually go into one of the child partitions. The problem is that I already have hundreds of millions of rows of ...
1
vote
1answer
41 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), ...
24
votes
3answers
15k views

Create index if it does not exist

I am working on a function that allows me to add an index if it does not exist. I am running into the problem that I cannot get a list of indexes to compare to. Any thoughts? This is a similar issue ...
3
votes
1answer
947 views

Postgres 9.1.6 Error index contains unexpected zero page at block 0

I have setup streaming replication on Postgres 9.1.6 running on a debian server and it's going on fine. When I try to run a query on the replica DB I get the error below: ERROR: index ...
0
votes
1answer
27 views

PostgreSQL database connection time [on hold]

how to check how much time PostgreSQL database takes for making connection?
0
votes
1answer
19 views

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 ...
0
votes
1answer
140 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 ...
0
votes
2answers
311 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 ...
2
votes
1answer
48 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
votes
2answers
42 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 ...
5
votes
3answers
157 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 ...
1
vote
1answer
485 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 ...
1
vote
1answer
29 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 ...
2
votes
1answer
35 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 ...
0
votes
0answers
19 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 ...
0
votes
0answers
20 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 ...
0
votes
0answers
26 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. ...
1
vote
0answers
25 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
votes
1answer
78 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
votes
1answer
170 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 ...
3
votes
2answers
600 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.
2
votes
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 ...
4
votes
2answers
182 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 ...
1
vote
0answers
43 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 ="*" + ...
0
votes
2answers
58 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: ...
1
vote
1answer
153 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 ...
0
votes
0answers
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 ...
4
votes
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 ...
0
votes
0answers
29 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 ...
0
votes
2answers
58 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 | ...
1
vote
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
votes
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 ...