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Historical DISTINCT over temporal data

I have some data that changes over time. To represent this, my tables have a valid_range column that stores the time-range when the row was valid. Here I'm using a range of ints to simplify things. ...
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1answer
175 views

Postgres rewriting entire table

We have a database that is just over 200 gb in size, with around 430 million rows, a primary key and a spatial index. Every few weeks we get an update which involves around 3 million rows, deleting ...
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114 views

Can I speed up the psqlodbc driver?

I have a SQL Server Integration Services 2012 package that copies data from SQL Server 2012 to Postgres 9.3. I'm using the latest version of the psqlodbc driver (9.3.210) but I only can transfer ...
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1answer
230 views

Multi-valued range subtraction

I have a table (actually a query, but I think it's the same thing) with two range columns. I need to perform a 'subtraction' on the two ranges. Precisely, I need Intersection(a, Complement(b)). Since ...
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1answer
261 views

group by and display contents of last row for each result

I've got some data of two objects and I want to retrieve the last row of both the objects, preferably in one query. Table structure: CREATE TABLE data ( pid serial NOT NULL, dt timestamp without ...
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1answer
107 views

ORDER BY that doesn't contain repeating values

Relevant SQL Fiddle (postgres 9.2) How do I state a SELECT .. ORDER BY .. that avoids having repeated values for a column? That is, for rows of the column "rank" (1,3,3,1) how do I get a result so ...
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0answers
82 views

Postgres Replication From Different Masters?

I'm getting a Postgres 9.3.3 install sorted out. My application is Drupal (so read/write), but low-traffic, so all application traffic is sent to the primary master. I have two sites (main and ...
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1answer
530 views

Is there a way to show a string instead if numeric column has specific value?

I have a float column called "weight". It's default is -1, showing the object wasn't weighted. Is it possible to show string "unweighted" instead of any negative number in the field? As it is ...
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1answer
275 views

Alternatives to NULL for missing data [duplicate]

I am using PostgreSQL and trying to write value constraints. Is it possible to record missing data as distinct from NULL values in a numeric field without using an arbitrary numeric value? For many ...
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1answer
2k views

Postgres database level encryption

I want to have the whole database to be encrypted, instead of encrypting the data before storing into database. Is it possible to encrypt the whole postgres database and what best method to use? ...
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1answer
90 views

Restoring a Postgresql database

Last week one of my sites server crashed. I was not able to access the ssh server and could only use the basic linux console on digitalocean.com. Because I could not get into my ssh server I was not ...
2
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1answer
3k views

Create index on very large table with many shared values

I'm looking to create an index on a large table (~50 million rows) on a field with lots of non-unique values. Table schema looks like: Column | Type | Modifiers | Storage | Stats ...
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1answer
2k views

ERROR: loop variable of FOREACH must be a known variable or list of variables

I have few FOREACH loops in my functions. The loops seem to perfectly agree with the official postgresql documentation. This error message is returned: ERROR: loop variable of FOREACH must be a known ...
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0answers
84 views

Postgres SQL Database Recovery

I am recovering a corrupted database, which may not really of had problems, but the server did. The host has restored a backup of the VM image (Ubuntu 12.04 LTS), however, its 10 days old, which is ...
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2answers
3k views

How to delete rows from a table when we're joining and return data?

I have two queries: The first one is as below: SELECT * FROM batch bp INNER JOIN sender_log sl ON sl.id=bp.log_id AND bp.protocol='someprotocol' The second query is used to delete rows: ...
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1answer
3k views

I have an INSTEAD OF trigger, but PostgreSQL still complains while I insert into view

I have created a view and an INSTEAD OF trigger for inserting/ updating/ deleting from that view. Now I have tried to insert some data to the view, and PostgreSQL returns following error (translation ...
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2answers
125 views

Rows into Column

I want to make the above view vConsolPrchOrd like below: Database: PostgreSQL 9.2 I want to create a Crystal Report with this view (I asked about this on Stack Overflow).
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1answer
146 views

PostGis getting rid of the lat long from table

This question is related to this question : Order by distance Now my tables have changed a bit. Table cafes now doesn't have latitude, longitude columns instead there are table addresses which ...
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1answer
16k views

Update all columns from another table

I need to update a table from another one, and I need to update all columns. Besides listing every column in the SET clause, is there a way to update them all at once? Like this: update tableA set * ...
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1answer
825 views

Change posgresql 9.3 slave roll password

I need to change the password on my slave posgresql server, because the person who set it up left the password the same as the password for the super user account on our other server. When I run ...
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2answers
301 views

High volume data aggregation

I need to aggregate incoming data and save the resulting aggregates to a table. A sample of the data is below. id,time 1967,2014-04-12 00:42:55+00 1967,2014-04-12 00:42:51+00 1972,2014-04-12 ...
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1answer
339 views

WAL archiving from a standby backup strategy Postgresql 9.3

I am trying to figure out if wal archiving from a standby is possible and a viable option for a backup strategy on Postgresql 9.3. The idea is to be able to take regular base backups and wal ...
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1answer
3k views

Is there a First() aggregate function in postgresql that returns the exact same type as the input?

Full question re-write I'm looking a First() aggregate function. Here I found something that almost works: CREATE OR REPLACE FUNCTION public.first_agg ( anyelement, anyelement ) RETURNS anyelement ...
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1answer
278 views

What happens when we call pg_dump while users are still using the system?

We have a web application with PostgreSQL as our database and use celery background tasks for somewhat complex task. At the very beginning of this complex task we take a backup of the database using ...
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1answer
428 views

PostgreSQL - Out of memory on count group by query

I'm trying to execute the following statement in PostgreSQL database: create table tmp_nodes as select node_id,count(way_id) as count from way_nodes group by node_id; This query fails because the ...
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0answers
81 views

Adding additional condition significantly degrades performance

Have the following query: SELECT * FROM table_A INNER JOIN table_B ON /* conditions */ INNER JOIN table_C ON /* conditions */ INNER JOIN table_D ON /* conditions */ WHERE table_B.state = 'active' ...
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1answer
7k views

Difference between now() and current_timestamp

In PostgreSQL, I use the now() and current_timestamp function and I see no difference: # SELECT now(), current_timestamp; now | now ...
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1answer
165 views

Database design for small startup

For a small startup that doesn't have much expected traction in the very beginning. We are currently working with only one postgres database without replications and at risk of failures. I've done ...
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0answers
608 views

Postgresql JDBC Table Valued Parameters [closed]

MSSQL has a great feature called Table Valued Parameters. It allows you to pass a table of a custom data to stored procedures and functions. I was wondering what is the equivalent in PostgreSQL, if ...
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2answers
3k views

Returning empty string when string_agg has no records

I am trying to return a text field in a PostgreSQL query that is of the form 'stringOne' || string_agg(field, ',') || 'stringTwo' where for certain elements in the group clause, field is always ...
3
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1answer
202 views

How to create function(table_name) that returns a set of the table

I have a set of tables that share the same fields (some timestamps and users names used for version control). I need to create a function with dynamic sql that uses a table_name and a timestamp as ...
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1answer
183 views

Merge left outer join column

I have a query that use left outer join. something like that : select issues.id, journal.notes from issues left outer join on (issues.id = journal.issue_id and journal.notes != '') So far it ...
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4answers
3k views

PostgreSQL 9.3 on Ubuntu Server 12.04 v.s. MS SQL Server 2008 R2 on Windows 7 Ultima

I have searched many articles in Google about the performance of PostgreSQL vs MS SQL 2008 R2 and found that many of those articles say the performance of PostgreSQL is better than that of MSSQL 2008 ...
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1answer
1k views

Is there a psql equivalent of bash's reverse-search-history?

I am very fond of bash's reverse-search-history (C-r) (command-line feature): Search backward starting at the current line and moving ‘up’ through the history as necessary. This is an incremental ...
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2answers
3k views

Unnest multiple arrays into rows

I have been shown a great way to bulkinsert with this example: WITH p AS ( INSERT INTO parent_table (column_1) SELECT $1 RETURNING id) INSERT INTO child_table (parent_table_id, ...
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2answers
1k views

postgresql being slow on count distinct for dates

I have a very simple, but very big, table. Its schema is like this (yadda int, yadda1 int, yaddate date, ... other stuff). Now, yaddate has an index by itself and it is also in other indexes ...
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1answer
2k views

Unable to Start PostgreSQL. kernel's SHMMAX parameter exceeded you limit

When I am trying to start my PostgreSQL I get the following error in the Postgresql.log file: FATAL: could not create shared memory segment: Invalid argument DETAIL: Failed system call was ...
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1answer
354 views

Postgresql condition on subquery results

This is a new question based on the solution to my previous question I have the following tables: users int (pk) user_id date last_visit int (fk) local_site sites int (pk) site_id site_stats ...
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1answer
1k views

Insert a file into PostgreSQL BYTEA field using PHP

The previous answers have been horribly complex for the scope of this project. I want to take the $_POST result as a variable and insert it into a BYTEA field of a table. $_SESSION['username'] = ...
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1answer
606 views

Postgresql not using GIN trigram index when performing non-ASCII LIKE query?

Steps to reproduce Create database CREATE DATABASE citiesdb WITH OWNER = citiesowner ENCODING = 'UTF8' TABLESPACE = pg_default LC_COLLATE = 'C' LC_CTYPE = 'C' ...
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1answer
895 views

While importing 150 GB file on Amazon RDS, why connection is failing?

I am having Postgres database dump file of 150 GB on Amazon EC2 instance. While dumping the data on RDS from EC2 server I am getting error. The output of the command is as given below. It's giving ...
3
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2answers
183 views

Tuning Postgres for Single connection use? Or is postgres wrong tool?

Any rules of thumb for work_mem, maintenance_work_mem, shared_buffer, etc. for a database that DOESN'T anticipate concurrent connections and that is doing lots of aggregate functions? I'm a social ...
0
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0answers
103 views

Update query taking 8x times in hot standby environment of Postgresql

I configured streaming replication (hot standby) and tested the update query on it. The update query is taking 8 times more when compared with stand-alone PostgreSQL (9.2 version) system. Some ...
2
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1answer
181 views

Recovering a partial PostgreSQL archive

I have $PGDATA/base but nothing else. It was taken from an installation after the postgreSQL service was shutdown, so is clean. Is there any way to recreate the other elements in $PGDATA that allow ...
4
votes
1answer
3k views

How do I sort the results of a recursive query in an expanded tree-like fashion?

Let's assume you have a nodes tables like this: CREATE TABLE nodes ( node serial PRIMARY KEY, parent integer NULL REFERENCES nodes(node), ts timestamp NOT NULL DEFAULT now() ); It ...
3
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2answers
507 views

How slow is slow in postgres?

I'm working with postgres for the first time. I have a lot of experience with small / medium size data analysis (i.e. things that fit in ram and can be analyzed in R, Stata, Matlab, etc.), but am now ...
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1answer
339 views

What's better here - a single column or multicolumn primary key?

Let's assume you have a table groups and a table item. Each item belongs to exactly one group. It is an inherent part of that group. An item cannot exist outside of a group and it cannot be moved to ...
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1answer
491 views

Why write ahead logs in PostgreSQL are generated every second

PostgreSQL version 9.2 generates write ahead log (WAL) every second i.e. 60 WALs are generated in one minute. Is it possible to make them occur less frequently? Is it possible to increase the WAL ...
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1answer
1k views

Increased performance from single statement, multiple row inserts?

I'm currently obsessing over bulk inserts via prepared statements with libpqxx. I am far from a database expert and even further when it comes to Postgres, but just thinking superficially, it doesn't ...
0
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1answer
161 views

PostgreSQL extending UPDATE query

I have the following update query to populate a table storing user stats users: int (pk) user_id date last_visit int (fk) local_site sites: int (pk) site_id site_stats: int (fk) site_id ...