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99 views

benefit of using [md5] over [trust] authentication for local Unix sockets

I am following a PostgreSQL installation guide that advises (subsequent to installing the database for the first time), to setup a password for the postgres user: alter role postgres password '<&...
6
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3answers
7k views

remove password requirement for user postgres

I understand that, upon installation, PostgreSQL has no password for its db root user (postgres): postgres=# select usename, passwd is null from pg_shadow; usename | ?column? ----------+---------- ...
2
votes
1answer
140 views

Copying database to different hard disk

Total noob at database administration here, excuse my ignorance. I have a server running a Rails application that's using PostgreSQL. The database is saved on drive /z/, which seems to have filled up....
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1answer
1k views

How to create a tablespace on Windows 7 for Postgresql 9.2?

I try to run this simple command: CREATE TABLESPACE tb_rec OWNER postgres LOCATION 'd:/tablespaces'; However, the tablespace is not created and I got this message: ERREUR: n'a pas pu ...
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1answer
153 views

pgbench-tools failed authentication

I'm trying to configure pgbench-tools and went to run it per the README and got this error -bash-4.2$ ./newset 'Initial Config' psql: FATAL: Ident authentication failed for user "postgres" psql: ...
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1answer
3k views

Why “SET LOCAL statement_timeout” does not work as expected with PostgreSQL functions?

My understanding is that PostgreSQL functions are executed similar to a transaction. However, when I tried to "SET LOCAL statement_timeout" within a function, it did not work. Here's how it works ...
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2answers
830 views

Using pg_dump and psql to transfer table with timestamp into another Db

I am using the following pg_dump and psql command lines through the terminal in order to transfer my table from one database to another. pg_dump -U postgres -t public.table1 database1 | psql -U ...
1
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1answer
109 views

How can prevent writes to a Postgres schema for a period of time?

I am moving a schema from one server to another using pg_dump + pg_restore + drop schema cascade. I need to know that no applications are writing to it (or at least that the writes will fail) during ...
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1answer
306 views

After upgrade from 9.1 to 9.3, commands still point to 9.1

Upgraded from 9.1 to 9.3 on my Ubuntu 12.04 server. Everything worked great but running commands like 'createdb' still runs them from the 9.1 path. /usr/lib/postgresql/9.1/bin/createdb: unrecognized ...
2
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1answer
3k views

copy data from public schema to another schema in postgresql

I'm creating a multi-tenant RoR app using PostgreSQL 9.3.5 running on linux (Ubuntu 14). I'd like to copy the data from my public schema to another schema. I tried: pg_dump -U my_username -h ...
2
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1answer
653 views

Change constraint on column based on value of another

Is it possible to change a constraint on a column in postgres based on the value of another column? E.g. (pseudocode): CREATE TABLE transactions( id SERIAL PRIMARY KEY, type TXN_TYPE NOT NULL,...
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228 views

PostgreSQL queries slower than before?

I am using PostgreSQL 9.3 server on my production server. Everything had been working fine for the past couple of months. But since the past week or so, PostgreSQL seems to have becomes very slow with ...
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3answers
893 views

pgAgent Job's “last result” is continuously “running”

I am using PostgreSQL-9.3 on Ubuntu-14.04 and using "/usr/share/pgadmin3/pgagent.sql" I have configured my pgAdmin3 to use pgAgent. postgres is my maintenance Db and I have run the pgagent.sql content ...
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0answers
193 views

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 (...
2
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0answers
306 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 ...
0
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1answer
575 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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0answers
140 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 ...
1
vote
1answer
119 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 ...
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3answers
845 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
129 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 ...
1
vote
1answer
348 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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0answers
832 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
339 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. ...
2
votes
1answer
188 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 ...
0
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1answer
70 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 ...
4
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1answer
5k 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
88 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 ...
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0answers
200 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
496 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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1answer
3k 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 ...
1
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1answer
1k 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
433 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
74 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 ...
2
votes
1answer
213 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 ...
1
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1answer
81 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
2k 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
183 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 ...
0
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1answer
3k 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 ...
2
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2answers
347 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', '831'...
3
votes
1answer
138 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 ...
0
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1answer
40 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
683 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;
0
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1answer
157 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 ...
1
vote
1answer
684 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 ...
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0answers
79 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 ...
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0answers
136 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 ...
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2answers
5k 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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1answer
122 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
votes
1answer
377 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, ......
0
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1answer
52 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 | ....