Linked Questions
47 questions linked to/from Measure the size of a PostgreSQL table row
4
votes
1
answer
12k
views
Calculate storage size of rows? [duplicate]
In a multi-tenant only one DB, one column is used to isolate customers data, that is customer_id.
Is it possible to get the storage size of a certain customer in all tables?
- 301
8
votes
0
answers
150
views
How to do Statistics in Partial Indexes of PostgreSQL efficiently? [duplicate]
This answer motivated think again my following tables but I am still uncertain how to store variables/results from data analysis for quick selection in post-processing.
If stored, I think it is well ...
0
votes
0
answers
77
views
Calculating the row size of a table [duplicate]
Is there a way to calculate the row size (in bytes) of a particular table in postgresql / pgadmin3?
- 999
93
votes
4
answers
98k
views
Should I add an arbitrary length limit to VARCHAR columns?
According to PostgreSQL's docs, there's no performance difference between VARCHAR, VARCHAR(n) and TEXT.
Should I add an arbitrary length limit to a name or address column?
Edit: Not a dupe of:
...
- 1,275
129
votes
3
answers
66k
views
Is a composite index also good for queries on the first field?
Let's say I have a table with fields A and B. I make regular queries on A+B, so I created a composite index on (A,B). Would queries on only A also be fully optimized by the composite index?
...
- 1,741
53
votes
2
answers
63k
views
Best way to populate a new column in a large table?
We have a 2.2 GB table in Postgres with 7,801,611 rows in it. We are adding a uuid/guid column to it and I am wondering what the best way to populate that column is (as we want to add a NOT NULL ...
- 755
49
votes
2
answers
57k
views
Configuring PostgreSQL for read performance
Our system writes a lots of data (kind of Big Data system). Write performance is good enough for our needs but read performance is really too slow.
The primary key (constraint) structure is similar ...
- 593
28
votes
5
answers
90k
views
SELECT DISTINCT on multiple columns
Supposing we have a table with four columns (a,b,c,d) of the same data type.
Is it possible to select all distinct values within the data in the columns and return them as a single column or do I ...
- 1,956
54
votes
1
answer
59k
views
Indexes: integer vs string performance if the number of nodes is the same
I am developing an application in Ruby on Rails with the PostgreSQL (9.4) database. For my use case, columns in tables will be looked up very frequently, as the whole point of the application is ...
- 643
46
votes
1
answer
18k
views
Would index lookup be noticeably faster with char vs varchar when all values are 36 chars
I have a legacy schema (disclaimer!) that uses a hash-based generated id for the primary key for all tables (there are many). An example of such an id is:
922475bb-ad93-43ee-9487-d2671b886479
There ...
- 713
37
votes
1
answer
57k
views
VACUUM returning disk space to operating system
VACUUM usually does not return disk space to operating system, except in some special cases.
From the docs:
The standard form of VACUUM removes dead row versions in tables and indexes and marks the ...
- 625
24
votes
2
answers
78k
views
PostgreSQL "size of temporary files"
I've imported data into a new database (about 600m rows of timestamp, integer, double).
I then created some indexes and tried to alter some columns (got some out of space issues), the database is ...
- 821
25
votes
1
answer
22k
views
What is the overhead for varchar(n)?
I wanted to ask for the meaning of this fragment from Postgres doc regarding varchar(n) type:
The storage requirement for a short string (up to 126 bytes) is 1 byte
plus the actual string, which ...
- 353
19
votes
1
answer
15k
views
Postgres: check disk space taken by materialized view?
I know how to check the size of indexes and tables in Postgres (I'm using version 9.4):
SELECT
relname AS objectname,
relkind AS objecttype,
reltuples AS "#entries", pg_size_pretty(relpages::...
- 333
14
votes
1
answer
8k
views
How do completely empty columns in a large table affect performance?
I have 400 million rows in a Postgres db, and the table has 18 columns:
id serial NOT NULL,
a integer,
b integer,
c integer,
d smallint,
e timestamp without time zone,
f smallint,
g timestamp without ...
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