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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Multiple databases with medium tables or Single database with huge tables

I've developed a shop management software using Postgresql and JAVA. I would like to know which of the solutions below is the best one for my specific situation: Only one database with huge tables ...
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145 views

Cannot drop a Postgres table

I want to drop a few tables in my postgresql database. I am able to drop a few tables but there are 3 tables which I am unable to drop. I need to drop a few tables in my Postgres DB. I tried the ...
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61 views

Calculate Quantity On Hand By Location

How can I calculate quantity on hand by location and validate the proposed location quantities against inventory transaction? Currently, I do not track location. I calculate total QoH via the ...
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1answer
305 views

PostgreSQL import XML to empty database, automatically create columns

The server is Linux but the development machine is Windows so I'm using psql command line. I tried \i C:/Users/John/Desktop/Parts.xml which did not work so either \i doesn't work with XML or I'm ...
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99 views

Looking for a recipe to merge multiple rows to single row

I have a aggregation table that is written by multiple processors (around 20). Each row has a composite key - location-id, campaign-id,... and aggregate stats about it. I need to merge the ...
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1answer
86 views

Will switching from Concrete Table Inheritance to Single Table Inheritance improve the performance of my queries?

I currently have an application that allows people to view and share 10 different types of posts (ex SportsPost, WorldNewsPost, TechnologyPost, etc). All posts types are conceptually the same, but ...
5
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3answers
556 views

How to understand the PostgreSQL discrepancy between connection pool recommendation ((2 * n_cores) + n_disks) and support for 100s of connections?

From PostgreSQL docs: Number of Database Connections -> How to Find the Optimal Database Connection Pool Size for optimal throughput the number of active connections should be somewhere near ...
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2answers
108 views

Need help designing a database

We are designing a system which holds statistical parameters about a particular user. As the users use the system the statistics change and the updated statistics are stored in the database. So for a ...
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1answer
120 views

How to manipulate join order of PostgreSQL optimizer?

I am working on table join order optimization. While query processing, I want to get table join order generated by optimizer, and update it by using my own algorithm in PostgreSQL? How can I update ...
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264 views

How to enable implicit casts in PostgreSQL >=9.2?

Coming from this topic on SO a user suggest me to enable implicit casts in my PostgreSQL and I don't know how to do that. I also don't know if this is a good practice or if it's the solution to the ...
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3answers
151 views

Get latest status of an item in the database

I have this table: ID|Item-FK |timestamp|status ============================= 1 | 123 | ... | OK 2 | 123 | ... | FAILED ... I want to query get all items which last status was FAILED. ...
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1answer
103 views

EXECUTE within function not using index?

I have an accounts table with ~200k rows and an index for these columns: account_type_id BIGINT , member_id BIGINT , external_id VARCHAR(64) CREATE INDEX account_full_qualifiers_idx ON ...
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1answer
54 views

Database Security - Prevent column writing?

I am using a Postgres db. I am concerned if someone gets in my DB, they could change the price of my products to $0 and download my products. Am I able to prevent writing / editing of that column ...
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1answer
2k views

Postgresql doesn't accept replication connection

Plain old streaming replication. PostgreSQL: 9.2.7 Windows 8.1 64 bit My primary and secondary clusters are on same windows machine. I have already done pg_start_backup() and everything, so both ...
0
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1answer
58 views

Does PostgreSQL have a variable character storage layer that optimizes storage space by automatic dedupe?

My application has a Product and a Purchased table. The Purchased table includes a full copy of the Product row at time of purchase, so that, even if a product name or description was changed, the ...
2
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0answers
103 views

How can I avoid breaking Postgres sync replication when building a large index?

We have pairs of Postgres 9.2 servers using synchronous replication. Sometimes rebuilding an index on a large table will break replication due to WAL segments not being kept around long enough. We are ...
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1answer
103 views

PostgreSQL roles versus users, grant permissions

I'm currently learning the differences between PostgreSQL and MySQL as I've got a new project and I also intend to migrate my existing software from MySQL to PostgreSQL. I've actually started creating ...
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43 views

Does Postgres shutdown gracefully when I restart my Mac?

When I restart my Mac OS X computer, I assume the daemon controlling Postgres (the "Postmaster" as I recall) is notified by the OS and performs a graceful shutdown of any running databases with ...
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1answer
1k views

Error: /var/lib/postgresql/9.3/main is not accessible or does not exist

I have a PostgreSQL db that was running on my server. I tried to do a db_dump and got a weird error message. I eventually thought I would just restart PostgreSQL. However its now stopped and won't ...
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1answer
676 views

How to migrate postgreSQL on EC2 instance to AWS RDS?

I have a large PostgreSQL DB (around 100GB) which is on EC2. I want to migrate it to RDS. How can I achieve this with minimal downtime?
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1answer
204 views

Postgresql cluster over nfs

Can I create a HA postreges cluster using two different nodes via NFS? According to the postgresql 9.4 official doc this isn't a good idea but I don't find any other info on the web.
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1answer
63 views

Are PostgreSQL dynamic arrays more wasteful than plain text?

Today, someone was helping me to make a function in PostgreSQL. I was wanting the function to return in arrays of 100+ geometries per two columns instead of delimited text to make it easier to ...
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1answer
131 views

encrypt data without performance issues?

I've googled around for the last 45 minutes or so and it seems like that I can't figure out what kind of options I got when it comes up to encryption in databases. Problem: I got a SaaS product and ...
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1answer
47 views

Matching a value with every element of a set of values - Postgresql

I'm new in Postgres and I can't achieve what I'm trying to do. I have a list of films in a Films table ID_FILM FILM NAME 1 Terminator 2 Forrest Gump 3 Nueve reinas A ...
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2answers
726 views

why pg_restore ignores --create ? Error: failed: FATAL: database “new_db” does not exist

I am trying to run following command: sshpass -p "pass" ssh x@1.2.3.4 "pg_dump -Fc -U foo some_db" | pg_restore --create --dbname=new_db I get: failed: FATAL: database "new_db" does not exist
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1answer
95 views

script for restore of postgres database localy from dump given on stdin - ambiguous redirect

Runing this command: sshpass -p "pass" ssh x@1.2.3.4 "pg_dump -U foo some_db" runs perfectly fine. It returns on stdandard output the dump of db. Then I would like to restore new_db based on dump ...
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1answer
707 views

Query optimization for multiple joins postgres

ER Diagram Brief description The database to be used is postgres. The database might contain upto 2 million AccountHolder records. Since the AccountHolder table is accessed and updated frequently ...
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2answers
158 views

Call UPSERT function multiple times to different inputs

I have a function: merge_vehicles(vid, cid, vname, reg_no, name, name_1st) Can i call it multiple times on inputs like (2335, 55, '246BDH', '246BDH', '811', 1), (2336, 55, '038THX', '038THX', ...
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1answer
124 views

Why postgres is using an odd index with no relation to the query

(Debian 7, Postgres 9.3, dedicated machine with huge cache) I have one big table called process_data (14gb) and another tiny lookup table called process_location. I'm doing a query between these two ...
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1answer
38 views

multi-column FKs with NULL values

I understand that in PostgreSQL if there is a multi-column FK from table B to table A and one or more of the FK columns in table B are nullable then the FK is still considered as "honored" for the ...
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2answers
315 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;
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512 views

pgpool-II Master Slave mode / Load Balance Mode / Watchdog On result many primary servers

I installed pgpool-II in Centos6.5, Master Slave mode / Load Balance Mode / Watchdog On but three postgresql servers are all primary server, shows as below: IP Address Port Status Weight ...
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1answer
71 views

PostgreSQL: Why is the schema owner not the database owner

I've a simple question, yet I am unable to find the answer from the official documentation. When I create a database in PostgreSQL as a specific user, I'm the owner of all the objects under the ...
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1answer
405 views

Postgres JSON field for many to many relationships

I'm designing a schema that has a many-to-many relationship as such: A lead can have several stages and each stage can have several leads. I currently have three tables, with one of them as being a ...
0
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0answers
74 views

Best way to handle multiple query keys

I am designing a postgresql database for an online card game. I want to provide users with the option to access their play history - users can see log of their games. The data I want to save has the ...
2
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0answers
93 views

How to optimize update using join in postgresql

I'm using PostgreSQL 9.3.5 on a CentOS system. I have a very large table (twenty million rows, 50+ column) that aggregates data from a few hundred systems. Several times a day each of the systems ...
2
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2answers
2k views

Check whether empty strings are present in character-type columns

I have an application that (as part of its logic) trims strings and replaces empty strings with NULL prior to insertion in the database. I guess one way to ensure that this is enforced would be to ...
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0answers
100 views

Optimizing SELECT queries

I'm not very experienced with database query optimization. I've been reading through similar questions here and Postgres tuning articles online, but unfortunately I haven't had any luck. Here's what I ...
0
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1answer
76 views

sorting by partial key name in json column

I have column document with data type json. I save here data for logging. So document has: {blocks: { participant-information_primary__Primary__39011__2288960: first_name: Firsst name, ...
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1answer
40 views

For each record, count records dated earlier in PostgreSQL

I have a table that contains a column year. I need, for each row, calculate the number of entries where the year is less than that in the row. So that the output would look like: col1 | col2 | ...
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0answers
39 views

Join does not not use index in PostgreSQL?

I have a statement that selects from two tables news and status. It seems that the index on the column status of the table news is not used. This table has about 70.000 rows and the query costs too ...
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1answer
130 views

Best design to handle multiple query keys [closed]

I am designing a postgresql database for an online card game. I want to provide users with the option to access their play history - users can see log of their games. The data I want to save has the ...
0
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1answer
72 views

modeling data dimensions as columns - some dimensions are highly variable while others have low variability

Please excuse my question if it is a bad one - I am not a DBA... I would like to model the following data: Let's say that I have one column that is the row id as generated by a sequence. Let's also ...
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1answer
44 views

MySQL data to Postgres every X time

Our team (Uni students) have a project that we are updating. Old project team has a Live MySQL database. We want to make a archive/warehouse from it in PostgreSQL. My question is: How can we import ...
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1answer
188 views

Deadlock detected on CREATE TABLE in PostgreSQL

I'm creating multiple tables asynchronously when I get deadlock detected. Both tables (Table A & B) have FK to one table (Table C) and I get deadlock on relation to Table C. Scripts CREATE TABLE ...
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1answer
28 views

Is it possible to set a timeout for optimization in PostgreSQL?

In PostgreSQL is there a timeout when the optimizer stops the optimization process and returns the least expensive plan it has found so far? Is it possible to change its value?
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88 views

Pgpool load-balancing vs. consistency

In what ways is consistency weakened when using pgpool-II load-balancing on Postgresql servers running streaming replication? Obviously with asynchronous replication you can insert a row on the ...
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1answer
224 views

Postgres automatic failover, multiple clients to multiple masters

I'm looking into providing a method of having multiple hot spare PostgreSQL instances to our website. The majority of implementations that I have found require a single point of failure with PgPool ...
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1answer
304 views

Order specific columns in json_agg

I want to sort the rows inside the json_agg function. I found this: PostgreSQL : select columns inside json_agg Which gave me a solution to selecting specific columns for json_agg, but now I want to ...
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2answers
98 views

Equality in JOIN or WHERE clause? Efficiency and style

Of the two queries below, which is the most efficient for postgresql? And which has better style in terms of readability, etc. The difference is the placement of the statement doctor.type != ...