DZone
Database Zone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
  • Refcardz
  • Trend Reports
  • Webinars
  • Zones
  • |
    • Agile
    • AI
    • Big Data
    • Cloud
    • Database
    • DevOps
    • Integration
    • IoT
    • Java
    • Microservices
    • Open Source
    • Performance
    • Security
    • Web Dev
DZone > Database Zone > PL/Perl and Large PostgreSQL Databases

PL/Perl and Large PostgreSQL Databases

PL/Perl is particularly useful for extracting data from structured text documents. Its elements combine to create a great procedural language for PostgreSQL.

Chris Travers user avatar by
Chris Travers
·
Jan. 30, 17 · Database Zone · Tutorial
Like (1)
Save
Tweet
3.34K Views

Join the DZone community and get the full member experience.

Join For Free

One of the topics discussed in the large database talk is the way we used PL/Perl to solve some data variety problems in terms of extracting data from structured text documents.

It is certainly possible to use other languages to do the same, but PL/Perl has an edge in a number of important ways. PL/Perl is lightweight, flexible, and fills this particular need better than any other language I have worked with.

While one of the considerations has often been knowledge of Perl in the team, PL/Perl has a number of specific reasons to recommend it:

  1. It is lightweight compared to PL/Java and many other languages
  2. It excels at processing text in general ways.
  3. It has extremely mature regular expression support

These features combine to create a procedural language for PostgreSQL that is particularly good at extracting data from structured text documents in the scientific space. Structured text files are very common and being able to extract, for example, a publication date or other information from the file is very helpful.

Moreover, when you mark your functions as immutable, you can index the output, and this is helpful when you want ordered records starting at a certain point.

So for example, suppose we want to be able to query on plasmid lines in UNIPROT documents but we have not set this up before we loaded the table. We could easily create a PL/Perl function like:

CREATE OR REPLACE FUNCTION plasmid_lines(uniprot text) 
RETURNS text[]


LANGUAGE PLPERL IMMUTABLE AS
$$

use strict;
use warnings;

my ($uniprot) = @_;
my @lines = grep { /^OG\s+Plasmid/ } split /\n/ $uniprot;

return [ map {  my $l = $_; $l =~ s/^OG\s+Plasmid  \s*//; $l } @lines  ];
$$;


You could then create a GIN index on the array elements:

CREATE INDEX uniprot_doc_plasmids ON uniprot_docs USING gin (plasmid_lines(doc));


Neat!

Database PostgreSQL

Published at DZone with permission of Chris Travers, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

Popular on DZone

  • Top 5 Programming Languages in AI: A Comparison
  • Java: Why Core-to-Core Latency Matters
  • Comparing Distributed Databases
  • The Definitive Guide to Building a Data Mesh With Event Streams

Comments

Database Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • MVB Program
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com
  • +1 (919) 678-0300

Let's be friends:

DZone.com is powered by 

AnswerHub logo