Questions tagged [postgresql]

All versions of PostgreSQL. Add an additional version-specific tag like postgresql-11 if that context is important.

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Why does RDS PostgreSQL always recover on restart?

I am running an RDS instance of PostgreSQL 9.6.3: select version(); returns PostgreSQL 9.6.3 on x86_64-pc-linux-gnu [...]. I have found that after issuing a stop from the RDS console followed by a ...
7
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1answer
670 views

Postgresql with just index storage

I have a PostgreSQL table with a key (bigint) and a value (double). The table has tens of billions of rows. I have a single btree on the (key,value) for aid lookups by key. The table is never updated. ...
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0answers
51 views

Find friends of friends (recursively) efficiently using Postgresql

Objective: Users submit their Contact Books and then application looks for connections between users according to their Phone Number. Something like "6 Handshakes" idea (https://en.wikipedia....
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2answers
2k views

How to exclude tables when using pg_dumpall with postgresql?

If use pg_dump, it has a --exclude-table-data option to ignore special table. But pg_dumpall command doesn't has that option. So how to exclude several tables when dump all databases?
6
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1answer
2k views

How can I determine why a concurrent Postgres index was marked as INVALID?

I'm trying to create an index concurrently. CREATE INDEX CONCURRENTLY blocks_expr_idx6 ON blocks USING btree ('blah') WHERE "type" = 'user root'; 12 hours after I ran the query, if I run \d ...
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0answers
2k views

Why does pg_last_xact_replay_timestamp() sometimes return extremely old timestamps?

In PostgreSQL 9.5, to monitor streaming replication lag, I use a combination of: pg_current_xlog_location() pg_last_xlog_replay_location() pg_last_xact_replay_timestamp() The first two functions are ...
6
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411 views

Roles and policies in Postgresql 9.5 row-level security

Following the the info in posts like these i would like to use the role system and policies, i.e. each user in my system would have a db role. I want to model the following properties but i can't come ...
6
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3k views

PostgreSQL trigram GIST vs. GIN indexes

I have a PostgreSQL 9.1 database that contains 10M+ rows and some text fields that need similarity and %word%-like searches, so I decided to use trigram indexes. Initially, I started to use GIN ...
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3answers
5k views

How to configure replication from PostgreSQL (RDS) to vanilla PostgreSQL?

I have an Amazon RDS Postgres DB and I created a "replicator" user and granted it the "replication" privilege. db=> create role replicator login password 'something'; CREATE ROLE db=> alter ...
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0answers
593 views

AWS RDS postrgres massive disk use, small tables

I can't figure out why our AWS postgres server has consumed all of it's space. We just had to up the storage space allocated to it, but can't find any hint from postgres that it's using that much ...
5
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1answer
1k views

Is there a strategy to use timestamp as primary key?

The majority of times we use integer sequences for primary keys to maintain uniqueness of row in a table. Couldn't we use timestamps instead of integers for this purpose? Is there any flaw in that ...
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1answer
2k views

Why am I getting permission denied on an ownership change?

My current user is pronto mediapop_staging=> select current_user; current_user -------------- pronto (1 row) This user a standard super user created on AWS RDS. mediapop_staging=> \du ...
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1answer
757 views

Test Driven Design for postgres procedures

I am looking to introduce a test driven design style to writing my stored procedures for a postgresql database implementation. I have seen that pgTap is a popular unit testing tool for postgres and ...
5
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1answer
631 views

How to limit work_mem on PostgreSQL

As an analyst I love having the ability to turn up the work_mem on occasion when a big sort or index build is in the offing. As a DBA, the idea of random users being able to request an arbitrarily ...
5
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1answer
342 views

PostgreSQL - How does multicolumn B-Tree index work with order by on 1st column and IN lookup for 2nd?

I created such table (similar to example from http://use-the-index-luke.com/sql/example-schema/postgresql/performance-testing-scalability ) CREATE TABLE scale_data ( section NUMERIC NOT NULL, ...
5
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4answers
946 views

How to run pg_dump so that it doesn't slow down other connections?

I am running a daily pg_dump on PostgreSQL 9.3.14 database of approx. 50 GB of size: pg_dump -Fc dbname > file The problem I am having is that while pg_dump runs, which takes several hours, all ...
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4k views

Postgres 9.6.1 Full Text Search dictionaries for most spoken languages

Using Mac OSX Yosemite 10.10.5, I am trying to run full text search operations, such as to_tsvector, to_tsquery, etc and have a need for dictionaries in about 80+ languages. Postgres seems to only ...
5
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0answers
632 views

How to minimize access exclusive table locks while reducing bloat or ALTER (ing) a table?

In some circumstances, I've been told not to do a VACUUM FULL (or CLUSTER) of a table that is in production, because that will exclusively lock it for longer than wished. The same might apply to ...
5
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1answer
4k views

postgres backup for specific table with blob oid

I have a table which has an oid column. When I'm taking a backup of this table, it takes complete oids (complete blob / oids backup). But my table only has 10 entries (which is approximately 30 ...
5
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0answers
2k views

Slow Postgresql query with left join

I have a query on Postgres, and I also have added proper index. Is there anything missing here? SELECT orders.*, demo.name as d_name FROM orders LEFT JOIN users as demo ON demo.id = orders.dr_id ...
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0answers
1k views

Moving extensions in AWS RDS (Postgres)

Initially we installed all extensions in default "public" schema. Now we have more and more other schemas - thus we want to add extensions and common functions to the schema common. Unfortunately AWS ...
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506 views

Inconsistent equality checking of Unicode text in Postgres 9.5?

Using PostgreSQL 9.5. It seems like Postgres is being inconsistent with how it compares strings similar to لى. A unique constraint is considering some strings equal that GROUP BY is considering ...
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2k views

postgres \copy file to RDS timeout

Postgres version 9.3, hosted on Amazon RDS. I have a messages table with 10G of data. I connected the database using psql on the EC2. Then used \COPY (select * from messages) TO '/tmp/messages.csv' ...
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0answers
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How to modelling a union type in PostgreSQL

We have the generic idea of a rule with specific implementation details stored in their own table. We currently have the following schema: Rule * id * name * ruleAId * ruleBId * .... * ...
5
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1answer
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Poor performance in my pgpool cluster

I've configured a postgres cluster with pgpool2 using the following link. The replication seems to be ok, but I ran some benchmarks (pg_bench) and the performance is lower than a single node, for ...
5
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1answer
286 views

Guidelines on best indexing strategy for varying searches on 20+ columns

I’m running a search engine for cars. It’s backed by a postgresql 9.3 installation. Now I’m unsure about the best approach/strategy on doing index optimization for the fronted search. The problem: ...
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405 views

Best practices for keeping protobuf spec in sync with relational database (e.g. PostgreSQL)

1. We have a schema definition in Google's Protocol Buffers format that we use to generate code for different gRPC implementations (Python, PHP) 2. We have a database (PostreSQL) that is initialized ...
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0answers
369 views

Using AWS RDS Postgres: Create a superuser with access to all tables (also future created ones)

In AWS RDS (A managed Database service), we cannot create real superusers. There is a user RDS calls Master User, which can create new users, databases, tables, etc. However, when another user has ...
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0answers
71 views

PostgreSQL 10 backend processes

I have a particular issue with PostgreSQL 10: Postgres creates backend processes for each connection on different ports. The problem is that some of our apps also use many ports and sometimes they ...
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0answers
2k views

Postgres stuck on IO/LWLock

I have an instance running Postgres v PostgreSQL 10.3 (Debian 10.3-1.pgdg90+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 6.3.0-18+deb9u1) 6.3.0 20170516, 64-bit. We have several indexes, GIN ...
4
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1answer
320 views

Calculating balance sheet with a single query

I have this schema for double entry bookkeeping system: CREATE TABLE account ( id INTEGER PRIMARY KEY, name TEXT NOT NULL, parent_id INTEGER REFERENCES account(id), UNIQUE (name, ...
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0answers
1k views

PostgreSQL Enum : Search on ENUM type

Defined an ENUM CREATE TYPE currency AS ENUM('GBP', 'EUR', 'USD'); Using this as a type in a table CREATE TABLE if not exists transaction( id BIGSERIAL NOT NULL PRIMARY KEY , amount NUMERIC(35,...
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0answers
186 views

PostgreSQL autovacuum ignoring “inactive” tables resulting in “transaction id wraparound”

I have a PostgreSQL database with a lot of tables (currently 93k) and I'm seeing issues with transaction id age threatening wraparound, because autovacuum is not getting triggered for clean tables ...
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0answers
2k views

Queries running very slowly in Amazon RDS PostgreSQL read-replica

We have been maintaining a project which has both web and mobile application platform. The backend of the project is developed in Django 1.10 and deployed in AWS. At the beginning, when there were ...
4
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1answer
70 views

Create WAL at interval, but only if data changed

I have a PostgreSQL 8.4 installation, and I have configured the archive_timeout setting to 5 minutes to improve the odds that I always have complete WAL file to apply in case of system failure. ...
4
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0answers
73 views

How to analyze postgres client process/session memory

Is there a way to check how much of process memory is allocated for the specific buffer for a running postgres session (work memory, temp buffers, plan cache etc ... )? I'm asking because i want to ...
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0answers
2k views

PostgreSQL High Disk I/O

I am evaluating PostgreSQL as an alternative to Oracle. I have a database with 533 Tables which contain up to 250,000 entries. For a performance comparison, I built the datbase both on Oracle and ...
4
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0answers
170 views

Could a query be still active after pgAdmin4 crashed?

As i am asking in the title, I am wondering if a query can be still active after pgAdmin4 crashed ? Indeed I was running a very long-time query.. CREATE TABLE intersection as ( SELECT buff.rownum ...
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0answers
4k views

AWS RDS Postgres Logical replication

I am using AWS RDS Postgres's and RDS's logical replication support (Edit: Note, this is not the same as the logical replication featurein PostgreSQL 10. It's AWS RDS functionality based on the same ...
4
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0answers
303 views

Is it possible to create a user defined type with plpgsql or SQL?

Distinct from a DOMAIN I was wanting to know if it was possible to create a user-defined type without C. Specifically I wanted to create a type like this CREATE TYPE name ( INPUT = ...
4
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1answer
1k views

Slow postgres query that uses quick sort instead of hash-aggregate

I'm on postgres 9.5 and working with a web-analytics database that records visitor traffic. I'm trying to optimize a very slow query gives me a count of the unique people that visited a given page ...
4
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1answer
388 views

PostgreSQL is not using index with large data

Enviroment My PostgreSQL (9.2) schema looks like this: CREATE TABLE first ( id_first bigint NOT NULL, first_date timestamp without time zone NOT NULL, CONSTRAINT first_pkey PRIMARY KEY (...
4
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1answer
691 views

Postgresql: How to avoid encoding issues when copying a schema from one server to another?

I am using pg_dump and pg_restore to move a schema from one Postgresql 9.5 server to another. On the destination server: $ pg_dump -h source.example.com -n my_schema -v --no-owner -F c -f my_schema....
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0answers
458 views

PostgreSQL full text search: How to change what classifies as a “word separator”?

Using ts_debug I can see what symbols Postgres treats as (what I call) a "word separator". Example: SELECT ts_debug('english', 'Hello. ABC') Result: (asciiword,"Word, all ASCII",Hello,{...
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1answer
756 views

What can I do to monitor “out of shared memory” issues?

I'm new to database administration and I would really like some advice on what tools I could use or what I could do to monitor "out of shared memory" issues. I've been seeing these "out of shared ...
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0answers
8k views

Postgres “could not receive data from client: Connection reset by peer.”

I have a cakephproject got a error when the project reload and it seem the error Database connection "Postgres" is missing, or could not be created. I have checked the error it will show error could ...
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0answers
1k views

Insertion into postgres database stops (hangs) after table reaches a certain size without error

We are currently trying to insert a large amount of data, about 27 million records with 200 columns, into a single table in a postgres 9.4 database. (Yes it is probably better to refactor the table ...
4
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0answers
314 views

Postgres: CREATE INDEX, but very slowly, to reduce performance hit on rest of database?

I have a large production PostgreSQL (9.1) database running on Ubuntu Linux. It is currently being queried and used. However there is another use I need later, and I will need to create a large (...
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0answers
1k views

Preventing Infinite Trigger Loops in PostgreSQL

I am working with two PostgreSQL databases (one internal and one on our company Web server) where I am attempting to share data between the two instances through the use of triggers. The databases ...
4
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1answer
3k views

How to deal with large offsets in select?

Table jtest with 200k rows, each row contains jsonb { id: "<uuid>", key: <index> } (<index> is integer 1-200k incremented per each row). There is also btree index on data->'key'. ...

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