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2answers
1k views

PostgreSQL get first letter of each word (except…)

I don't think I drank enough coffee today, but stuck on this for some reason. Trying to get the first letter of each word, except a few stopwords. Example "The United States of America" -> "USA" ...
3
votes
2answers
162 views

How to tell which indexes are not being used

Postgresql 9.3 Debian 7 I have a lot of huge indexes in a legacy database I'm trying to optimize. Thinking about dropping all the useless ones, but how can I tell how often they are used and if they ...
0
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1answer
163 views

hierarchical retreival of records in postgresql

I am using postgresql-9.2 . I have a table of products which stores the information about the products and its child table is content table , which contains the products linked to it. PRODUCT MASTER ...
1
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0answers
179 views

Multischema view for postgres , querying multiple databases

Im managing SaaS app where each customer has a separate database (Postgres 9.3) . I need to figure out the best way to aggregate and query this data ( READ-only ). I know postgres has problems with ...
7
votes
3answers
13k views

GROUP BY one column, while sorting by another in PostgreSQL

How can I GROUP BY one column, while sorting only by another. I'm trying to do the following: SELECT dbId,retreivalTime FROM FileItems WHERE sourceSite='something' GROUP BY seriesName ...
0
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1answer
124 views

Row-level subquery caching?

I have a query that uses a CTE which contains millions of rows. I plan to call this query many times, and the CTE returned each time will have most of the same rows. Is it possible for me to cache the ...
2
votes
0answers
637 views

Stack Depth Limit Exceeded (After delete trigger)

CREATE TABLE parent ( parent_id VARCHAR(30) PRIMARY KEY ); CREATE TABLE child ( parent_id VARCHAR(30) REFERENCES parent ON DELETE CASCADE, child_id VARCHAR(30) PRIMARY KEY ); CREATE OR ...
1
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1answer
362 views

Import binary database file into postgres

I have a quite newbie question that I do not know if is possible or not: I had to format my computer, and the only way to keep my postgres database was accessing to data with my folder browser (...
1
vote
1answer
42 views

Index on integer column not helping. Help? (EXPLAIN ANALYZE output inside)

The table market_trades has an integer column market_id which takes values from 1 to 5. This seems like a pretty straightforward query to get the number of trades on each market: WITH markets AS ( ...
1
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1answer
59 views

Optimizing a query on a large table (EXPLAIN ANALYZE result inside)

I have a table market_trades with a timestamp column: api_production=# \d market_trades; Table "public.market_trades" Column | Type ...
-2
votes
2answers
75 views

Indexing into two “buckets”

I'm creating a database with PostgreSQL that has an integer field called "delay". All of my queries on this column will be checking if the value of this column is less than or equal to 0, or greater ...
0
votes
1answer
27 views

Determining which database instance makes biggest IO

Assuming that I have a dedicated server on which I am running multiple instances of mysql and postresql servers. How without iotop determine which instance in particular time (proc/pid/io shows data ...
2
votes
4answers
146 views

Make IN clause behave like AND clause

I've asked the same question on stackoverlow, but got no answer, so that's why I'm asking it here (I've read that simple sql questions should be asked at SO, but I have no choice). Suppose I have 3 ...
6
votes
1answer
2k views

PGAdmin III Server Status Error: Could not read directory “pg_log” No such file or directory

Running PostgreSQL 9.3 on Ubuntu 14.04 and pgAdmin III 1.18.1 on Windows 7. I tried Tools->Server Status and I get an error: "Could not read directory "pg_log" No such file or directory" I ...
0
votes
1answer
120 views

How to access pg_settings from separate connection

I am trying to access the pg_settings table from a separate connection belonging to a legacy application. I know how to identify the connection's procid from pg_stat_activity, but I am unsure how to ...
1
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0answers
272 views

How to measure bandwidth requirements for MySQL, Postgres, …?

TLTR: how to configure MySQL/Postgres to get a fair measurement of the I/O requirments for analytical queries? Hello, for certain database and especially database hardware experiments for want to ...
2
votes
0answers
9 views

Active record relation AND filtering [duplicate]

(Edit: since reposted to dba.stackexchange.com and answered there). Suppose I have 3 models: Post, PostCategory and Category. I'm implementing some kind of page with filters where I can filter posts ...
4
votes
1answer
1k views

How to optimise window queries in postgres

I have the following table with approximately 175k records: Column | Type | Modifiers ----------------+-----------------------------+-----------------------...
0
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1answer
400 views

How to create a Postgres trigger to ensure field is non-updateable

I'm trying to create a Postgres trigger to ensure after a column's value has been set, it cannot be updated (basically make it readonly). So far I've come up with the following draft trigger. 1) ...
1
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1answer
324 views

Create user to monitor database activity on Postgres

Postgres 9.3 Debian 7 I want to create a monitor user called monitor that the only permission is to run queries to monitor all the database activity. I created the user and it can select from ...
2
votes
2answers
565 views

Adding standard set of constraints (rules) to PostGIS `raster` type column

Following on from my related prior question, let me elaborate this topic a bit. raster2pgsql is a raster loader executable that loads GDAL supported raster formats in PostGIS. It has a -C flag ...
0
votes
1answer
155 views

Need some help with this query or some ideas for change it to better model

I've a dilemma in my application and I don't get how to solve it at DB level. The idea is that a user can be subscribed to one or more services but services are show depending on user type. This can ...
3
votes
5answers
491 views

Find all values not present for other values of other column

Let's suppose I have a table with integer columns a and b (each pair (a,b) is unique) and following data: a | b ------- 1 | 2 1 | 3 1 | 4 1 | 5 2 | 1 2 | 3 2 | 4 3 | 1 3 | 3 Now I need to ...
2
votes
1answer
180 views

Joining timestamped records with the most-recent-prior records from another timestamped table

Say I have 2 tables: Table: sales timestamp timestamp without time zone amount numeric Table: prices timestamp timestamp without time zone price numeric How can I get a ...
1
vote
1answer
930 views

Postgresql connection refused

I'm trying to remotely connect to my postgresql database. I have two virtual machines set up both running ubuntu 14.04. I am trying to connect to the second vm using the first vm using psql -h 10.0....
0
votes
0answers
57 views

Which benchmark assess string pattern matching in a database?

I have a postgresql DB in which I do a lot of string matching ala : UPDATE table1 SET colum1 = TRUE WHERE colum2 LIKE '%teststring%'; colum2 is a whole html file As I said I do A LOT of this and I'...
3
votes
1answer
882 views

timeline 2 of the primary does not match recovery target timeline 1

I want to create a configuration with postgresql and pgpool to get height availability (HA). I want to do this: .-----. .--------. | | W | DB | | APP |---...
1
vote
2answers
340 views

Creating a unique constraint on a PostGIS 'raster' type column

I am using the following command to add constraints to one of the raster image in PostGIS-2.1.3 (PostgreSQL-9.1.14). ALTER TABLE schema1.table1 ADD CONSTRAINT enforce_scalex_rast unique (rast); But ...
3
votes
3answers
754 views

How to ORDER BY typical software release versions like X.Y.Z?

Given a "SoftwareReleases" table: | id | version | | 1 | 0.9 | | 2 | 1.0 | | 3 | 0.9.1 | | 4 | 1.1 | | 5 | 0.9.9 | | 6 | 0.9.10 | How do I produce this output? | id | ...
0
votes
1answer
310 views

PostgreSQL SQL syntax - JOIN and substrings

I have a single table of hostnames and NFS exports, some but not all of which are related. Example entries: HOST VOLUME ----- ---------- host1 vol1 host1 vol2 host1 ...
2
votes
1answer
339 views

Searching a big table for a few results without scanning the whole table

I need to search a very big PostgreSQL table (500+M rows), I want to limit the returned search results, but using the "limit" keyword cant prevent the search over the whole set of data(is it correct?) ...
0
votes
1answer
388 views

Postgresql tries to connect to fe80::1, permission denied

I upgraded a couple of days ago to IPv6 on my local test machine and since then I've been experiencing some issue with connecting to my local PostgreSQL server. I set the host to 'localhost', which ...
1
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1answer
127 views

Update different columns on different clauses

I have a database table in Postgres 9.3 with the following layout: id SERIAL, col1 INT, col2 INT Whenever a new row is inserted, I will have to update ALL rows col1 and/or col2 in different cases ...
0
votes
0answers
279 views

cascade delete doesn't work even though constraint is added

I created the following table: CREATE TABLE message_link ( id serial NOT NULL, thread_id integer, message_id integer, user_id integer, read boolean NOT NULL, CONSTRAINT message_link_pkey ...
0
votes
1answer
268 views

PostgreSQL synchronous replication time out?

I'm using PostgreSQL 9.3 with synchronous replication. I have 2 synchronous replicators and 1 async replicator. My problem is when 2 synchronous replicators are down, transaction will wait ...
1
vote
1answer
2k views

Grant usage partially on schema to user on Postgres

I granted INSERT in a specific table for one user. The problem is that I need to also grant USAGE in the schema for this same user, but granting USAGE in schema also turn all relations in that schema ...
0
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0answers
50 views

Which primary keys must be specified when using slony PostgreSQL replication?

I'm extremely green when it comes to databases, so forgive my ignorance. I've been researching ways to replicate our production Postgres DB, and I've decided to try out Slony. Since the server is ...
1
vote
1answer
1k views

PostgreSQL Slave has more files in pg_xlog than /wal_archive

Background: for various reasons I am switching PostgreSQL Slave from a Streaming replication to a warm standby replication. The streaming replication was setup using this guide: http://technology....
1
vote
1answer
122 views

How to optimize multiple ORDER BYs?

I'm getting sluggish performance on a table with ~300,000 rows and B-Trees on each column. This is for a dynamic pagination page where the query is constructed on demand, and the application caches ...
9
votes
1answer
474 views

Busy table is not getting vacuumed

We're using Postgres 9.2 on Windows to store low-frequency timeseries data: we're inserting around 2000 rows per second every second 24 hours, 7 days a week with no downtime. There is a DELETE that ...
0
votes
2answers
101 views

How can I make this query more efficient?

This is the query: SELECT races.*, tmptimers.last_start_time, tmplaps.updated_at AS last_updated_at FROM races LEFT JOIN (SELECT * FROM timers WHERE timers.user_id = 1) AS tmptimers ON ...
2
votes
1answer
62 views

Understanding pg-pool in details

I have following problem regarding the pg-pool (3.3.3) When master fails, automatic failover happens and standby is promoted to master. But this new master don't have any replicators. Other slave ...
1
vote
1answer
117 views

how to update the value of a period contained inside a bigger range

I have a tsrange like '[2010-01-01 14:00, 2010-01-01 15:00]',20 And want to update the 20 value to 15 in a range inside that, like '[2010-01-01 14:10, 2010-01-01 14:30]',15 My expected outcome ...
3
votes
1answer
530 views

PostgreSQL: Trigger for updating view doesn't work

I'm trying to make the trigger for updating a view work. If I'm doing and INSERT it works! But when I'm trying to do an UPDATE it just doesn't run. CREATE OR REPLACE FUNCTION test_trigger_function() ...
10
votes
2answers
4k views

PostgreSQL: schema diff/patch tool [closed]

Consider the following setting: A production DB A dev db, on which schema changes are made to enable new features When the development of a new feature is complete, I have to manually update the ...
0
votes
1answer
206 views

Does PostgreSQL take time to start streaming replication after restart master?

I set streaming replication in postgresql 9.3. I have one master and 3 slaves and replication works fine. But when i restart the master server and login using postgres database, pg_stat_replication ...
0
votes
1answer
169 views

Unmount/detach/deactivate PostgreSQL database

I manage a server that serves several web applications that use PostgreSQL as a data store. Each web application has a separate role and database, and each database is stored exclusively on a ...
4
votes
1answer
2k views

PostgreSQL streaming versus file-based replication (In terms of server behavior & configuration)

I am trying to understand best uses of PostgreSQL replication and how it works so I can troubleshoot in a production environment. I am having a hard time understanding the differences between these 2 ...
1
vote
1answer
227 views

Optimizing bulk update performance in Postgresql with dependencies

Basically my question is the same as this one, but WITH dependencies, so drop/renaming the table is not a trivial option (I assume). We are refactoring a large, poorly designed table which has many ...
1
vote
1answer
699 views

PosgreSQL: very slow select on a single table with no joins

I'm trying to help a colleague who's having some problems with a PostgreSQL query. We've narrowed it down to a join to one table making the query painfully slow and, upon investigation, we found that ...