Performance tricks

Unlike text editors, the IDE provides much more features and tools and does a lot of different things aside of parsing and highlighting. Because of this IDE is always slower than a simple editor. Everything costs something.

Perl5 plugin was written by a perl fan, not a professional language plugins developer, so it's far from perfect. This fact causes more performance setbacks.

Some of performance issues are fixable and they will be fixed in time. With every new release the plugin becomes faster and faster. Others performance issues are result of the IDEA architecture and can't be fixed by plugin's author, but may be fixed by JetBrains, again, in time.

Still, there are some performance tricks you could use to make your work more comfortable.

Identifiers

Use long and self-explanatory variables and subs names if it's possible. get_something_this and $database_handler is much faster than gst and $dbh

I guess that thre are two reasons of short perl identifiers:

1. Historical. Perl has been originally created as admin command line tool, not a common programming language.
2. For a long time Perl has not any IDE and therefore - autocompletion.

Basically, when IDEA needs to find usages of the variable/sub, it takes all same words from the internal index and checks every found word, if it leads to this definition. And this being done not only when you explicitly trying to find usages. IDEA may do this for it's internal reasons.

Large files

Avoid using large files, keep your programs modular

This is a problem of plugin's parser. IDEA requires separate lexer and perser, so it's not possible to port native perl parser for it (perl parser and lexer works together). The easiest way was to use simple lexer and BNF with manual tunings for a parser. As a result - we have a descending perl parser.

Parser aside, the plugin has a lot of minor performance setbacks, that are being fixed from version to version.

What is considered to be a larget file depends on your hardware, but I found comfortable to work with few thousands lines of code in a single file.