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 ...
6
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1answer
1k 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 blocks ...
6
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1k 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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1answer
510 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. ...
6
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0answers
392 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 ...
5
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1answer
573 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
497 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
315 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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1answer
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?
5
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3answers
775 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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0answers
3k 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
607 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
3k 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 ...
5
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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 ...
5
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0answers
478 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 ...
5
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0answers
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' ...
5
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0answers
961 views

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
274 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: ...
5
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1answer
1k views

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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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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59 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 ...
4
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0answers
981 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
204 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
142 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 ...
4
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1answer
891 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 ...
4
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0answers
1k 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
62 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
67 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 ...
4
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0answers
164 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
3k 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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1answer
1k views

Does PostgreSQL/PostGIS use R-Tree or R*-Tree?

PostgreSQL and PostGIS offer to create indexes over GiST with pretty much the same code. On 2D items, "This gives R-tree behavior" is what it says in the PostgreSQL source comments. However, it is a ...
4
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0answers
273 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
1k views

Inserting in PostgreSQL Foreign Table Violates Primary Key Constraint10

I have two local databases in one of them I have created a foreign table that is referencing a table in the second database. When I want to insert in foreign table it inserts the primary key all over ...
4
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1answer
584 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....
4
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0answers
399 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,{...
4
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1answer
646 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 ...
4
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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 ...
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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 ...
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0answers
2k 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 ...
4
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0answers
2k 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'. ...
4
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1answer
228 views

Pagination - Text comparison with greater than and less than with DESC

I am implementing a seek method for pagination and am wondering about how to best query on a text column with DESC. The queries for this seek approach use a less than or greater than depending on if ...
4
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0answers
185 views

PostgreSQL/PostGIS: Query seems inordinately time-consuming

I'm doing what I would consider a pretty straightforward query on two tables that aren't huge (~626k records in one; ~47k records in the other). Both tables have GIST indices on their spatial ...
4
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0answers
4k views

Postgres Streaming Replication: How to re-sync data in master (with standby) after failover

I am absolutely new to postgres 9.1 replication mechanisms. I have managed to set up streaming replication between a master and standby postgres (Both have x number of records). At one point when ...
4
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0answers
1k views

Ways to process XML into a relational structure in Postgres

I have a database that is comprised of ~10 tables, most of which have many-to-many relationships with each other (and an associated join table). I am inserting of the order 100k XML files into a raw ...
4
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0answers
5k views

Achieve PostgreSQL hstore functionality in MySQL

Please suggest any MySQL 5.5+ Engine that can support collection of key-value pairs be stored in any column of a table. I don't know if this feature is available out of the box in MySQL like ...
4
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0answers
189 views

Postgres TupleTable like data structure

I'm writing my own Group by operator (non-hashed implementation) and I'm currently looking on a good data structure to store the result groups. There are two requirement in my mind: the table need to ...
4
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0answers
979 views

How to properly configure pgBouncer transaction level pooling?

What is a good way to determine the number of available transaction connections when using pgBouncer to pool database connections? Also, how should I determine the number of max_connections and ...
4
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0answers
3k views

Can PostgreSQL's COPY create CSV with Locale-specific number formatting?

I want to create a CSV with PostgreSQL 9.1 COPY that directly opens correctly with a double-click in crazy German Excel 2010. Using ";"-Delimiter is easy. The encoding is solved, but Excel only ...