1
vote
1answer
33 views

Increased performance from single statement, multiple row inserts?

I'm currently obsessing over bulk inserts via prepared statements with libpqxx. I am far from a database expert and even further when it comes to Postgres, but just thinking superficially, it doesn't ...
6
votes
2answers
106 views

Improve performance of COUNT/GROUP-BY in large PostgresSQL table?

I am running PostgresSQL 9.2 and have a 12 column relation with about 6,700,000 rows. It contains nodes in a 3D space, each one referencing a user (who created it). To query which user has created how ...
0
votes
0answers
62 views

Performance measurement in PostgreSQL

When developing server-side stored procedures performance measurement is an important issue. EXPLAIN ANALYZE is very usefull, but when it comes to simple queries like SELECT name FROM clients WHERE ...
1
vote
0answers
46 views

Do supertables produce bottlenecks?

There are several alternatives to using polymorphic associations and one of them is to use the so-called "concrete supertable". From my point of view, this is the neatest solution and is pretty easy ...
3
votes
1answer
69 views

Why does this limit make the postgres planner use a much slower index scan instead of a much faster bitmap heap/index scan?

I have a table of about 700k rows in Postgres 9.3.3, which has the following structure: Columns: content_body - text publish_date - timestamp without time zone published ...
2
votes
1answer
73 views

Debugging why postgres is snowballing with system cpu usage

I am having an issue where my postgres database which run on a dedicated machine is getting hammered with kernal level cpu usage. This essentially takes down the web service that run on this database. ...
1
vote
0answers
68 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 ...
1
vote
1answer
50 views

How can I improve performance of update query in PostgreSQL

I have a table with about 80 million records. I have added a new attribute (heigth_category) which I want to fill based on another attribute (heigth). If the heigth is between 0 and 6, I want to fill ...
0
votes
1answer
47 views

PostgreSQL - Return unique combinations of columns based on where clause

This is quite a long question, please bear with me. So I'd like to first explain I have a database of firewall logs created using the following command: CREATE TABLE firewall_logs_mapped ( ...
1
vote
0answers
111 views

Postgres database zero down time production deployment

I need some idea about how I can deploy a financial application in production environment using PostgreSQL DB with zero down time. I have two servers in Master-Slave design. Currently I am giving ...
3
votes
0answers
83 views

How to properly monitor the number of PostgreSQL database connections?

I tried to use a Nagios script for monitoring the number of database connections on a Postgres database and I reached this problem: these are counted as currently open-connections and measured every 5 ...
1
vote
0answers
42 views

Fastest way to get the length of the intersection of two text arrays in PostgreSQL

This is what I am currently using: CREATE OR REPLACE FUNCTION array_intersect(a1 anyarray, a2 anyarray) RETURNS anyarray AS $$ select array ( select unnest($1) intersect select unnest($2) order by 1 ...
0
votes
2answers
50 views

How to change table/indexes structure for a query with two aggregated colums

Do you have any suggestion on how to improve a table structure or its indexes in order to have a single query run faster? The table has this structure: docid | character varying(17) | ...
0
votes
1answer
151 views

Postgres 8.3 faster than 9.3?

Our software product currently ships on Windows 7 with Postgres 8.3 as its database. On a busy site, there may be 24 automated systems generating 100 rows (x100 columns) per minute, with 3-10 human ...
4
votes
1answer
92 views

PostgreSQL does not use all available IOPS on a single operation

Using PostgreSQL 9.3 on Windows 7x64, CoreI7, SSD. Assume a PostgreSQL table with 8 Int32 columns and following C# code to fill the table. using (var connection = new NpgsqlConnection("User ...
4
votes
1answer
736 views

MongoDB performance vs. PostgreSQL with 5.5 million rows / documents

Can someone help me compare these queries and explain why the PostgreSQL query executes in just under 2000ms and the MongoDB aggregate query takes almost 9000ms and sometimes as high as 130K ms? ...
3
votes
1answer
84 views

PostgreSQL: When should I use fillfactor < 100 for tables on SSD?

PostgreSQL documentation says that choosing smaller fillfactor lets table reserve space for future updates on the same page and "This gives UPDATE a chance to place the updated copy of a row on ...
0
votes
0answers
195 views

hstore vs redis performance wise (without durability) [closed]

How do PostgreSQL's Hstore and Redis compare performance-wise? This question was asked here, but I would like to compare with a PostgreSQL configuration without durability guarantee, i.e. with ...
3
votes
1answer
111 views

Query planner thinks doing a sequential scan on a very large table is faster than using an index?

I've got a query that selects the most favorited photo for each of the last 12 editions for a particular domain (this is just a segment of a larger query, but the problem seems to stem from here): ...
1
vote
1answer
80 views

Slow queries related to subqueries using aggregation

Here's a simplified version of the queries I am running: select ... from editions join edition_events on edition_events.edition_id = editions.id join events on events.id = ...
0
votes
0answers
80 views

Postgres chooses a bad query plan

The following query finishes in 1.5s (which is ok, the table contains about 500M rows): explain (analyze, buffers) select sales.* from sales join product on (product.id = sales.productid) join date ...
0
votes
1answer
129 views

Best read performance when every query is known, and the data doesn't change

I'm trying to maximise performance on an underpowered PostGIS server - 1 core, 4 CPUs. The data (OpenStreetMap) will be infrequently (monthly?) loaded, and never changes otherwise. Each of the 30 or ...
5
votes
2answers
483 views

Efficient query to get greatest value per group from big table

Given the table: Column | Type id | integer latitude | numeric(9,6) longitude | numeric(9,6) ...
0
votes
1answer
167 views

Simple PostgreSQL lookup table is inexplicably slow

I'm trying PostgreSQL 8.4.14 for storing triples, pieces of data of the form (String, String, String). For speed, I'm not repeatedly storing strings but rather using two tables: main table triples ...
0
votes
3answers
194 views

Performance of primary key IDs with gaps (but in sequential order)

I know that having non-sequential IDs is bad for index performance. But assuming all my IDs are created in correct order, but with large gaps: i.e: 154300000 283700000 351300000 464200000 ...will ...
0
votes
0answers
99 views

PostgreSQL 9.2 (PostGIS) performance problem

A month ago i got acquainted with PostgreSQL and only now i've noticed that some of my queries are pretty slow. Well, for example, i have table: CREATE TABLE sometable ( gid serial NOT NULL, geom ...
5
votes
1answer
400 views

TPS too high in PostgreSQL

I created a table: CREATE TABLE foo ( id integer primary key, bar integer NOT NULL ); and inserted one row: INSERT INTO foo (id, bar) VALUES (1, 1); and ran a pgbench of the following ...
0
votes
1answer
112 views

Entity with >150 attributes: One table or many tables with relationships

I have entity with 170 attributes. It's data from vehicle monitoring. Every entity has datatime label and unique id of gps terminal. Datetime and id of terminal - these are conditions for GROUP BY ...
5
votes
2answers
1k views

How to optimization database for heavy I/O from updates (software and hardware)

The situation I have a postgresql 9.2 database which is quite heavily updated all the time. The system is hence I/O bound, and I'm currently considering making another upgrade, I just need some ...
1
vote
1answer
1k views

Postgresql vs MySQL - Which is better for join queries & writing data(inserts) [closed]

I have to design a database which will end up with 50M records in a single table(there will be other tables with lesser number of records). I'm more concerned with join queries & writing ...
0
votes
0answers
47 views

Postgresql function taking long time on newly restored database

I have developed one function in my PostgreSQL database. It was taking 12-15 seconds to execute. Now I have restored a new PostgreSQL 9.0 dump using following command: pg_restore -hx.x.x.x -p5432 -d ...
1
vote
1answer
95 views

Benefit to keeping a record in the database, rather than deleting it, for performance issues?

So I have a client that I am building a Rails app for....I am using PostgreSQL. He made this comment about preferring to hide records, rather than delete them, and given that this is the first time I ...
1
vote
2answers
158 views

Optimize simple query using ORDER BY date and text

I have a query to a table in Postgres with an order based on a date field and a number field, this table has 1000000 records The data types of the table are: fcv_id = serial fcv_fecha_comprobante = ...
1
vote
0answers
172 views

How to configure pgpool for reasonable speed

I have a problem with pgpool II configured in master-slave mode with replication on slony. I have configured postgres databases on each server to run as fast as they can and this was verified by me ...
3
votes
1answer
287 views

Group By primary key or DISTINCT increase query time over 1000x with limit

Also see http://stackoverflow.com/questions/17741167/hibernate-jpa-improve-performance-of-distinct-query but I realized this is mainly a PostgreSQL issue. My application uses a 3rd party extension to ...
0
votes
1answer
252 views

Postgresql table with one integer column, sorted index, with duplicate primary key

I want to have a table in PostgreSQL with these properties: One column with an integer Allow duplicates in this column. Duplicates will be rare. Duplicates have no meaning logically and will be ...
2
votes
1answer
113 views

How to avoid large joins when determining which rows a user is authorized for?

Typical wep app situation: you have logged in users querying for resources exposed through an API. As a hypothetical example, company administrators quering for their employees' time sheets: company ...
1
vote
0answers
59 views

Performance of database with transactional data

There are lots of row modifications (several thousands of rows per minute) in our PostgreSQL database that stores transactional data. We have a problem because PostgreSQL runs vacuuming process and ...
1
vote
1answer
90 views

How un-clustered is a CLUSTER USING table

I have some tables which benefit greatly from CLUSTER ON/CLUSTER USING in Postgres SQL: # CLUSTER table USING index_name; # ANALYZE VERBOSE table; # CLUSTER VERBOSE; A maintenance task periodically ...
3
votes
2answers
999 views

Configuring PostgreSQL for read performance

Our system write a lots of data (kind of Big Data system). The write performance is good enough for our needs but the read performance is really too slow. The primary key (constraint) structure is ...
4
votes
1answer
82 views

Why do psql queries take longer when inserting many rows. Why is it non linear

So if I insert a single row into a postgres database it takes 18 ms. If I do this in a loop like this: INSERT INTO contacts (numbers) SELECT distinct array[ (random() * 99999999)::integer, ...
5
votes
2answers
3k views

Optimizing bulk update performance in Postgresql

Using PG 9.1 on Ubuntu 12.04. It currently takes up to 24h for us to run a large set of UPDATE statements on a database, which are of the form: UPDATE table SET field1 = constant1, field2 = ...
2
votes
1answer
517 views

PostgreSQL concurrent increment of counter

I need to maintain a statistical table for a project, composed by a list of items and their usage (Think about something like a website in which you would like to count pageviews). Each time an item ...
2
votes
2answers
251 views

How to implement posts with “seen by” like facebook?

Inside a Facebook group there is a feature when every time see the group newsfeed it mark all posts as seen by me. And if I see a specific post inside a group thought a url ...
4
votes
1answer
497 views

How to determine if there are [idle connections with] uncommitted transactions in PostgreSQL?

According to a comment on this question I asked about idle connections in PostgreSQL 9.2, some uncommitted transactions (possibly related to some of those idle connections) might cause some ...
5
votes
1answer
1k views

Could too many idle connections affect PostgreSQL 9.2 performance?

Some queries on my database server seem to take a long time to respond, and I believe the CPU usage is high. When running ps aux, I see ~250 "idle" connections (which I believe to be too many). I ...
3
votes
1answer
49 views

Does avg_query for PgBouncer include update and inserts?

Trying to tune our application and would like to know if the stats data that pgBouncer shows as avg_query, according to the PgBouncer docs on usage: avg_query Average query duration in ...
1
vote
1answer
2k views

Very slow DELETE in PostgreSQL, workaround?

I have a database on PostgreSQL 9.2 that has a main schema with around 70 tables and a variable number of identically structured per-client schemas of 30 tables each. The client schemas have foreign ...
6
votes
1answer
128 views

What is a good way to determine the performance I should expect from a PostgreSQL server?

Trying to figure out how I should expect my database to perform. Basically, I need to determine when the server I have set up is reaching its performance limits - which would help me plan server ...
4
votes
1answer
149 views

After Rackspace server creation, PostgreSQL query planner doesn't work as expected

We created an image of one of our database servers in Rackspace. Then, we created a new server using that image, expecting things to work. However, the index performance we have seen seems to be ...