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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PostgreSQL crash recovery

We are planning to use PostgreSQL in our application but are concerned about crash-safety and recovery. I can't find any database crash recovery method or process in PostgreSQL. I know there must be ...
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5answers
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What are the differences between “Stored Procedures” and “Stored Functions”?

So a comment from this question mentions, that there is a slight difference in "Stored Procedrues" and "Stored Funtions" in PostgreSQL. The comment links to a wikipedia article but some of this don't ...
12
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2answers
899 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 ...
9
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1answer
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PostgreSQL Database Data File Integrity Check

When running a PostgreSQL database system how do I know my database as a whole has 100% integrity? Basically how do I know if my data files and pages are all 100% good with no corruption? In the ...
7
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2answers
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Database for building a realtime analytics system

I want to build a system similar to Google Analytics (only used for internal use, less traffic and less feature), and mainly focus on Real time counting of unique URI visit/PV by different ...
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4answers
6k views

No NULLs, yet invalid byte sequence for encoding “UTF8”: 0x00

I've spent the last 8 hours trying to import the output of 'mysqldump --compatible=postgresql' into PostgreSQL 8.4.9, and I've read at least 20 different threads here and elesewhere already about this ...
6
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4answers
16k views

Why won't PostgreSQL 9.3 start on Ubuntu?

I have successfully installed PostgreSQL 9.3 from the APT repository on 2 VM's running Ubuntu 12.04 and 13.04...however, I cannot get it to install properly on my host machine running Ubuntu 12.04. ...
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2answers
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Possible to keep max number of records in postgresql?

Basically part of our Postgresql table is used to keep server access logs, and as such sometimes during production this can get pretty large. is there any way of setting in postgresql to have a ...
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2answers
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PostgreSQL maximize performance SSD

I will have a huge PostgreSQL 9.3 database with many tables with more than 100M entries per table. This database will be basically be read-only (once I fill all the necessary tables and build the ...
4
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1answer
946 views

Ways to speed up IN queries under PostgreSQL

I have a query of the following form: SELECT * FROM twitter_personas WHERE twitter_user_id IN ($1, $2, $3, ..., $25000) The IN query has anywhere from 10 to 25000 values. The query runs for minutes ...
3
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1answer
2k views

Cannot get my slave - replication server to start

My replication server will not start. I have followed the instructions here: http://opensourcedbms.com/dbms/setup-replication-with-postgres-9-2-on-centos-6redhat-el6fedora/ As well as several other ...
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2answers
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Creating High Availability Cluster with PostgreSQL

I am new to database design. I have a task to create a high-availability cluster. I Googled a lot, however I haven't found any good way to do this on PostgreSQL. Where should I start and what are ...
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3answers
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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 ...
11
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3answers
490 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
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2answers
3k 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 ...
8
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1answer
2k views

Why would you index text_pattern_ops on a text column?

Today Seven Databases in Seven Weeks introduced me to per-operator indexes. You can index strings for pattern matching the previous queries by creating a text_pattern_ops operator class index, as ...
8
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2answers
4k views

How to do incremental/differential backup every hour in Postgres 9.1?

Trying to do an hourly hot incremental backup of a single postgres server. I have the following setup in postgresql.conf: max_wal_senders=2 wal_level=archive archive_mode=on archive_command='copy ...
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3answers
512 views

What is retrieved from disk during a query?

Fairly simple question, probably answered somewhere, but I can't seem to form the right search question for Google... Do the number of columns in a particular table affect the performance of a query, ...
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1answer
730 views

Equality query on NVARCHAR column yields multiple results in SQL Server 2012

I am in the process of moving a pet project from PostgreSQL (9.2.2) to SQL Server (2012 Standard). I've noticed an interesting phenomenon when querying unicode words. Given the definition: CREATE ...
7
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1answer
634 views

Is the optimisation fence behaviour of a CTE (WITH query) specified in the SQL:2008 standard? If so, where?

I see frequent references to WITH queries (common table expressions, or CTEs) acting as an optimisation fence, where the server isn't permitted to push filters down into the CTE queries, pull common ...
6
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1answer
2k views

PostgreSQL: Unable to run repmgr cloned database

I'm running tests with PostgreSQL hot standby with 1 master, and exactly 1 slave. I am using the instructions on this guide: ...
4
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2answers
5k views

How to choose a collation for international database?

I'm designing a database which will store data in different languages (using UTF-8), so I think the best way to display the queries results is ordering it according to the user's language during the ...
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2answers
1k views

How do I know what indexes to create for a table

Is there a way I can figure out the best way to know which indexes to create for a table?
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2answers
2k views

Running pg_dump on a hot standby server?

Disclaimer: I admittedly haven't tried this yet, but I'm not sure I would know if it wasn't working correctly, so I wanted to ask. I would like to run a nightly backup job (via pg_dumpall) from a hot ...
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0answers
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Recovery when failover

1/ Description: I have 2 Centos machine: master, slave (streaming replication). Both of them are built on PostgreSQL 9.3 (image below) and configured failover event (failover PG 9.3 document). Last ...
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1answer
162 views

Postgresql 9.3 replication: Preventing wal-files from building up, if receiver goes offline

I have a streaming replication running between two servers. I just upgraded to postgresql 9.3 from 9.2. Earlier on in my 9.2 setup, I have tried that my slave server went offline due to a network ...
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3answers
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Should I manually VACUUM my PostgreSQL database if autovacuum is turned on?

I use software which makes a big PostgreSQL database (there is a table with a million rows in it) and the developers says I should VACUUM and ANALYZE periodically. But the PostgreSQL database default ...
2
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1answer
663 views

Use GIN to index bit strings

I'm trying to extend PostgreSQL to index bit strings up to 1000 bits. (These bit strings are created by quantization of high-dimensional vectors, so for each dimension up to 4 bits are assigned). ...
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2answers
4k views

PostgreSQL stored procedure to return rows or empty set

I have a stored procedure, which RETURNS SETOF ct_custom_type and inside I do RETURN QUERY EXECUTE 'some dynamic query' And I want to do this: If this 'dynamic query' returns >= 10 rows, I want to ...
15
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1answer
25k 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} ...
14
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6answers
9k views

Are there any good and free tools for managing a PostgreSQL database? [closed]

Before, I have used phpmyadmin to manage an MySQL database, but now I would like to manage a PostgreSQL database. The PostgreSQL database is on a server, but not a webserver, so I don't use PHP. Are ...
13
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1answer
581 views

Why is there a PostgreSQL Turtle?

I was just checking out the propaganda page for PostgreSQL and I found this little piece of art: It is the "Turtle Style" PostgreSQL logo. How old is this, and did PostgreSQL ever officially use a ...
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2answers
832 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?
9
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3answers
119 views

Combining separate ranges into largest possible contiguous ranges

I'm trying to combine multiple date ranges that may or may not overlap into the largest possible contiguous date ranges. For example: Data: CREATE TABLE test ( id SERIAL PRIMARY KEY NOT NULL, ...
9
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2answers
23k views

PgAdmin III - How to connect to database when password is empty?

I have installed PostgreSQL 9.1 on my PC (Win 7). I have a small Java application connecting successfully to it with login=sa and password="". The connection works. However, it is refused from ...
8
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1answer
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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 ...
8
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1answer
2k views

PostgreSQL pg_stat_activity shows COMMIT

We recently replaced our database server with an upgraded machine with 4 x quad core CPUs and 32Gb of ram. We also repurposed our old box to serve as a slave with streaming replication. Both boxes are ...
8
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2answers
627 views

Pros and Cons of Checking if value exist for unique column or let db raise unique error on inserting

While writing a query other day a thought came to me and have stuck in my mind. What is preferable, first checking if a value for a unique column exists and then inserting or insert and let db raise ...
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1answer
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MATCH FULL vs MATCH SIMPLE

I've noticed a MATCH SIMPLE or MATCH FULL option in phpPgAdmin, but I can't find a description in the docs. How do they function? The default is set to MATCH SIMPLE.
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4answers
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Should I invest the time to change the column type from CHAR(36) to UUID?

I have a few million rows in my database already. I didn't know about the PostgreSQL UUID data type when I designed my schema. One of the tables has 16M rows (about 3.5M to 4 M records per shard), ...
6
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2answers
1k views

Slow ORDER BY with LIMIT

I have this query: SELECT * FROM location WHERE to_tsvector('simple',unaccent2("city")) @@ to_tsquery('simple',unaccent2('wroclaw')) order by displaycount I'm happy with it: "Sort ...
6
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5answers
13k views

PostgreSQL: The database cluster initialization failed

Both C:\PostgreSQL and C:\PostgreSQL\data have postgres user with full access and admin rights. I ran postgresql-9.1.2-1-windows.exe from postgres user as admin. Target C:\PostgreSQL Every way I ...
5
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2answers
198 views

Managing CTE execution order under uncertainty

I am writing a large, multi-step CTE for performance reasons. In one query, data must be moved from one table to another, but the quantity of rows moved is uncertain and could be zero. In a ...
5
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1answer
170 views

For alignment optimized table is bigger than original table - why?

In another question I learned that I should optimize the layout from one of my tables to save space and have better performance. I did this, but ended up with a larger table than before and ...
4
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1answer
1k views

How do I decompose ctid into page and row numbers?

Each row in a table has a system column ctid of type tid that represents the physical location of the row: begin; create table t(id serial); insert into t default values; insert into t default ...
4
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1answer
9k views

Fixing table structure to avoid `Error: duplicate key value violates unique constraint`

I have a table which is created this way: -- -- Table: #__content -- CREATE TABLE "jos_content" ( "id" serial NOT NULL, "asset_id" bigint DEFAULT 0 NOT NULL, ... "xreference" varchar(50) ...
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2answers
551 views

Order of columns in a compound index in PostgreSQL (and query order)

I have a table with 50K rows. It is actually a PostGIS table. The query has 4 parts (1 mandatory) (3 Optional) intersection box (a geography rectangle) with 4 lat,long (I use st_intersects) ...
4
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2answers
2k views

PostgreSQL CREATE TABLE creates with incorrect owner

I'm using PostgreSQL 9.2.4. When I create a table as a non-superuser in a database owned by that non-superuser, it is owned by the postgres user, so I can't put any data into it unless I explicitly ...
4
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2answers
20k 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 ...
4
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3answers
698 views

Full Text Search With PostgreSQL

i have a table with this rows: Stickers ------------------------------------------------------ ID | Title |Keywords (ts_vector) ------------------------------------------------------ ...