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13
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1answer
9k views

Can listen_addresses really be set to a list?

I have a VM with IP address 192.168.0.192 running postgreSQL. If I specify listen_addresses = '*' then I can connect from another VM at 192.168.0.191 and from localhost. But I can't seem to use a ...
13
votes
1answer
5k 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. ...
13
votes
5answers
4k views

Efficiently select beginning and end of multiple contiguous ranges in Postgresql query

I've got about a billion rows of data in a table with a name and an integer in the range 1-288. For a given name, every int is unique, and not every possible integer in the range is present--so there ...
13
votes
2answers
378 views

Simultaneous calls to the same function: how are deadlocks occurring?

My function new_customer is called several times per second (but only once per session) by a web application. The very first thing it does is lock the customer table (to do an 'insert if not ...
13
votes
3answers
21k views

Automating failover in PostgreSQL 9.1

How does one setup two identical servers for automatic failover in PostgreSQL 9.1. OS Centos 5 PostgreSQL 9.1 compiled from source The postgres user account exists on both machines and has a ...
13
votes
2answers
7k views

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 ...
13
votes
3answers
3k views

Does PostgreSQL 9.1 Streaming Replication catch up after a lag without WAL archiving?

Context: Let's say that, while using Streaming Replication/Hot Standby on a Postgres 9.1 cluster, a standby node goes down. It stays down for an day, during which time a lot of DML occurs on the ...
13
votes
2answers
4k views

Streaming replication and failover on PostgreSQL

I am doing a proof of concept on PostgreSQL replication. After the discussion on forum we decided to go with streaming replication as the performance is good compared to other solutions. PostgreSQL is ...
12
votes
3answers
6k views

Postgresql: datatype for email address

What would be the right datatype to store email addresses in PostgreSQL? I can use varchar (or even text), but I wonder if there is a more specific data type for emails.
12
votes
3answers
9k views

Should I add an arbitrary length limit to VARCHAR columns?

According to PostgreSQL's docs, there's no performance difference between VARCHAR, VARCHAR(n) and TEXT. Should I add an arbitrary length limit to a name or address column? Edit: Not a dupe of Would ...
12
votes
7answers
10k views

Are there any good tools for monitoring postgresql databases [closed]

I am planing to have very soon few highly loaded postgresql databases. I have some expirience managing mysql databases with high load, but now we have to use postgresql. I want to know what are the ...
12
votes
2answers
1k views

Postgres query plan of a UDF invocation written in pgpsql

It's possible when using the pgadmin or plsql to get a hold of a query plan for a sql statement executed via a UDF (using EXPLAIN). So, how do I get a hold of the query plan for a particular ...
12
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2answers
1k views

How can I generate a random bytea

I would like to be able to generate random bytea fields of arbitrary length (<1Gb) for populating test data. What is the best way of doing this?
12
votes
1answer
9k views

postgresql: how do I dump and restore roles for a cluster?

Where are roles stored in a cluster, and how do I dump them? I did a pg_dump of a db and then loaded it into a different cluster, but I get a lot of these errors: psql:mydump.sql:3621: ERROR: role ...
12
votes
2answers
46k views

How to get the timestamp column in only milliseconds from PostgreSQL?

I have a column "created" with type timestamp without time zone default now() in a PostgreSQL database. If I select colums, it has a nice and readable format per default: SELECT created FROM ...
12
votes
3answers
2k views

Indexes for SQL query with WHERE condition and GROUP BY

I am trying to determine which indexes to use for an SQL query with a WHERE condition and a GROUP BY which is currently running very slow. My query: SELECT group_id FROM counter WHERE ts between ...
12
votes
2answers
1k views

Modelling constraints on subset aggregates?

This is a cross-post from Stack Overflow. I figured I might get more interesting thoughts here. I am using PostgreSQL but I figure most of the top-end db's must have some similar capabilities, and ...
12
votes
3answers
3k views

PostgreSQL: Can I do pg_start_backup() on a live, running db under load?

Our established replication has broken ("requested WAL segment has already been removed" during downtime) We cannot easily stop the master again. Can we do pg_start_backup(), rsync ${PGDATA}/ ...
12
votes
1answer
2k views

Choice of authentication approach for financial app on PostgreSQL

First some background. The LedgerSMB project is an open source financial accounting software project that runs on PostgreSQL. We implement a very large amount of business logic in user defined ...
12
votes
2answers
6k views

Refresh materalized view incrementally in PostgreSQL

Is it possible to refresh a materialized view incrementally in PostgreSQL i.e. only for the data that is new or has changed? Consider this table & materialized view: CREATE TABLE graph ( ...
12
votes
3answers
8k views

How to convert mysql to postgresql? [closed]

I am desperately looking for a conversion tool to convert a big mysql database to postgresql. I need the tool/script to be: Free Works under Linux Simple to use and not buggy You actually tried and ...
12
votes
1answer
6k views

How to migrate large blob table from mysql to postgresql?

I'm now in process of migrating my MySQL database to PostgreSQL. Almost everything went fine (well, after lots of googling for correct mysqldump params etc.) except one table I have - actually the ...
12
votes
2answers
850 views

What is the optimal data type for an MD5 field?

We are designing a system that is known to be read-heavy (on the order of tens of thousands of reads per minute). There is a table names that serves as a sort of central registry. Each row has a ...
12
votes
2answers
6k views

Foreign key constraint on array member?

Suppose I have a table containing job roles: CREATE TABLE roles ( "role" character varying(80) NOT NULL, CONSTRAINT "role" PRIMARY KEY (role) ); Suppose I further have a table, users, and each ...
12
votes
1answer
5k views

MATCH FULL vs MATCH SIMPLE in foreign key constraints

I've noticed a MATCH SIMPLE or MATCH FULL option in phpPgAdmin, but I can't find a description in the docs. The default is MATCH SIMPLE. How do they function?
12
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3answers
2k views

How to implement business logic permissions in PostgreSQL (or SQL in general)?

Let's assume I have a table of items: CREATE TABLE items ( item serial PRIMARY KEY, ... ); Now, I want to introduce the concept of "permissions" for each item (please note, I'm not talking ...
12
votes
1answer
4k views

PostgreSQL failover and replication

I'm evaluating PostgreSQL 9.1 and have few questions related to failover and replication details. I have few test scenarios. First one with a Master server and few Slaves. In case Master crashes I ...
11
votes
3answers
677 views

Can IS DISTINCT FROM be combined with ANY or ALL somehow?

Is a postgres way of combining IS DISTINCT FROM with ANY or some other neat way of getting the same result? select count(*) from (select 'A' foo union all select 'Z' union all select null) z where ...
11
votes
3answers
6k views

Should I use SQL JOIN or IN Clause?

I have a question about best approach. I am not sure which approach is best when data is considered variable in size. Consider the following 3 TABLES: EMPLOYEE EMPLOYEE_ID, EMP_NAME PROJECT ...
11
votes
2answers
24k views

Permission denied in Postgres

I added the user myuserto Postgres. Then I added the database mydatabase in the pgAdmin III GUI and restored from a backup file. So the owner of mydatabase is the superuser postgres. Then I tried to ...
11
votes
2answers
11k views

Preventing PostgreSQL from starting on boot in Ubuntu

I am using PostgreSQL 9.2 and it runs automatically when I start the system (Kubuntu). How can I avoid this? I need to start it manually, and I don't want it to start unattended because I need to ...
11
votes
6answers
12k views

How to convert a MySQL database to PostgreSQL?

Is there any command line tool for converting the MySQL database to PostgreSQL? I'd also like to know if there is a way to convert the database using the normal mysqldump command.
11
votes
2answers
3k views

Select longest continuous sequence

I am trying to construct a query in PostgreSQL 9.0 that gets the longest sequence of continuous rows for a specifc field. Consider the following table: lap_id (Serial), lap_no (int), car_type ...
11
votes
4answers
11k views

PostgreSQL designing tool [closed]

I am about to design a database which is going to run with PostgreSQL. I am used to the magnificent tool called MySQL Workbench for MySQL database. It is useful and it looks good which I kind of ...
11
votes
2answers
4k views

Force PostgreSQL clients to use SSL?

I have configured ssl = on in postgresql.conf (and installed a certificate etcetera). Does this ensure that all clients will always connect over SSL? (I.e. does ssl = on it make it impossible to ...
11
votes
2answers
136 views

PostgreSQL Recursive Descendant Depth

I need to calculate the depth of a descendant from it's ancestor. When a record has object_id = parent_id = ancestor_id, it is considered a root node (the ancestor). I have been trying to get a WITH ...
11
votes
3answers
314 views

Constraint to enforce “at least one” or “exactly one” in a database

Say we have users and each user can have multiple email addresses CREATE TABLE emails ( user_id integer, email_address text, is_active boolean ) Some sample rows user_id | ...
11
votes
1answer
5k views

How to preserve the original order of elements in an unnested array?

Given the string: 'I think that PostgreSQL is nifty' I would like to operate on the individual words found within that string. Essentially, I have a separate from which I can get word details ...
11
votes
1answer
3k views

Source several files at once with psql

I want to execute several sql scripts sequentially with psql as a single transaction to set up my database schema. What is the best way to do this? In the past I know I had a master script that I ran ...
11
votes
2answers
3k views

What happens in PostgreSQL checkpoint?

Here's part of my checkpoint log: 2014-03-26 11:51:29.341 CDT,,,18682,,532854fc.48fa,4985,,2014-03-18 09:15:24 CDT,,0,LOG,00000,"checkpoint complete: wrote 15047 buffers (1.4%); 0 transaction log ...
11
votes
1answer
2k views

Generate an exception with a Context

When PostgreSQL throws an exception, there is a line "CONTEXT" like: ERROR: INSERT has more target COLUMNS than expressions LINE 3: ... ...
11
votes
1answer
1k views

BLOBs or references in PostgreSQL

I need to store binary data files in a PostgreSQL database which runs on an Ubuntu server. Initially there will be a few dozen files of approximately 250kb in size each. However, the number of files ...
11
votes
1answer
4k views

ERROR: no schema has been selected to create in

I am working on an amazon RDS postgresql database where I know there had been some issue with the public schema (maybe it was dropped). But apparently the schema exists, and anyway the problem is not ...
11
votes
2answers
473 views

Biological Sequences of UniProt in PostgreSQL

What is the best way to store UniProt biological sequences in PostreSQL? Data Details We pull in 12 million sequences from UniProt - this number is likely to double every 3-10 month. The length of ...
11
votes
1answer
4k views

How to determine if there are [idle connections with] uncommitted transactions in PostgreSQL?

According to a comment on this question I asked about idle connections in PostgreSQL 9.2, some uncommitted transactions (possibly related to some of those idle connections) might cause some ...
11
votes
1answer
4k views

Database archive solutions

In continuation to a question posted by me on Is it a good idea to move high-volume and highly-accessed tables to a separate database?, am looking out for different techniques/solutions available for ...
11
votes
1answer
751 views

Why is my PostgreSQL ORDER BY case-insensitive?

I have Postgres 9.4.4 running on Debian and I get the following ORDER BY behavior: veure_test=# show LC_COLLATE; lc_collate ------------- en_US.UTF-8 (1 row) veure_test=# SELECT ...
11
votes
1answer
462 views

Disk file effects of delete and vacuum

I have a very frequently updated table with 240 million rows (and growing). Every three hours 1.5 million rows are inserted and 1.5 million are deleted. When I moved the cluster to a SSD this bulk ...
10
votes
3answers
15k views

Checking whether two tables have identical content in PostgreSQL

This has already been asked on Stack Overflow, but only for MySQL. I'm using PostgreSQL. Unfortunately (and surprisingly) PostgreSQL does not seem to have something like CHECKSUM table. A PostgreSQL ...
10
votes
3answers
5k views

How should I represent a latitude and longitude in Postgres without using PostGIS?

How should I represent a latitude and longitude in Postgres without using PostGIS? The system I am using does not allow SQL passthrough so I cannot use POSTGIS.