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@NikolayS
NikolayS / howto.md
Last active January 29, 2023 20:25
log_min_duration_statement = 0 and I/O impact

How to get an estimate of the impact of writing Postgres logs with log_min_duration_statement = 0:

  1. Do select pg_stat_statements_reset(); and wait N seconds (where N >> 60 – say 1-24 hours, covering typical busy hours). Remember when it was, and write down somewhere – this timestamp will be needed!

  2. Check if select count(*) from pg_stat_statements is lower than pg_stat_statements.max. If it's equal to it, then raise pg_stat_statements.max and restart with the step 1.

  3. Get the estimate:

\set TS_PGSS_RESET 'XXXX-XX-XX XX:XX:XX';
sudo apt-get update
sudo apt-get install python-virtualenv
sudo apt-get install python-dev
sudo apt-get install postgresql
sudo apt-get install postgresql-server-dev-9.3
sudo apt-get install redis-server
sudo -u postgres createuser -s sentry
sudo -u postgres psql -c "alter user sentry with password 'sentry';"

Why objects (usually) use less memory than arrays in PHP

This is just a small post in response to [this tweet][tweet] by Julien Pauli (who by the way is the release manager for PHP 5.5). In the tweet he claims that objects use more memory than arrays in PHP. Even though it can be like that, it's not true in most cases. (Note: This only applies to PHP 5.4 or newer.)

The reason why it's easy to assume that objects are larger than arrays is because objects can be seen as an array of properties and a bit of additional information (like the class it belongs to). And as array + additional info > array it obviously follows that objects are larger. The thing is that in most cases PHP can optimize the array part of it away. So how does that work?

The key here is that objects usually have a predefined set of keys, whereas arrays don't:

@nikic
nikic / objects_arrays.md
Last active April 12, 2024 17:05
Post explaining why objects often use less memory than arrays (in PHP)

Why objects (usually) use less memory than arrays in PHP

This is just a small post in response to [this tweet][tweet] by Julien Pauli (who by the way is the release manager for PHP 5.5). In the tweet he claims that objects use more memory than arrays in PHP. Even though it can be like that, it's not true in most cases. (Note: This only applies to PHP 5.4 or newer.)

The reason why it's easy to assume that objects are larger than arrays is because objects can be seen as an array of properties and a bit of additional information (like the class it belongs to). And as array + additional info > array it obviously follows that objects are larger. The thing is that in most cases PHP can optimize the array part of it away. So how does that work?

The key here is that objects usually have a predefined set of keys, whereas arrays don't:

@samdark
samdark / devmeeting.md
Last active December 11, 2015 17:28
Встреча разработчиков, Воронеж #1
@fomigo
fomigo / gist:2382775
Created April 14, 2012 07:59
Russian Plural Form in PHP
<?php
/*
echo plural_form(42, array('арбуз', 'арбуза', 'арбузов'));
*/
function plural_form($n, $forms) {
return $n%10==1&&$n%100!=11?$forms[0]:($n%10>=2&&$n%10<=4&&($n%100<10||$n%100>=20)?$forms[1]:$forms[2]);
}