One of the problems we've had with running large-scale hosting systems
for StatusNet is enabling new plugins. If the plugin is not enabled,
its database tables are not checked at script time. Conversely, if it
is enabled, it may take several hours to run checkschema for tens of
thousands of sites -- during which time users might see DB errors.
A new argument to checkschema lets it pre-load one or more plugins
before checking the schema. This lets us prepare the plugins' database
tables before they're used in production. In a multihome environment,
this can be combined with tags to gradually roll out a new plugin.
In the config file, a stanza like:
$site = Status_network::getFromHostname(...);
if ($site->hasTag('fooenabled')) {
addPlugin('Foo');
}
...will only enable the plugin on certain sites. Meanwhile, a bash
script like this should gradually enable the plugin:
# For all sites...
for site in `php allsites.php`; do
# Update the schema for the Foo plugin
php checkschema.php -s$site.wildcard -xFoo;
# Enable the Foo plugin
php settag.php -s$site.wildcard fooenabled;
done
like leprous boils in our code. So, I've replaced all of them with //
comments instead. It's a massive, meaningless, and potentially buggy
change -- great one for the middle of a release cycle, eh?
UserActivityStream -- used to create a full activity stream including subscriptions, favorites, notices, etc -- normally buffers everything into memory at once. This is infeasible for accounts with long histories of serious usage; it can take tens of seconds just to pull all records from the database, and working with them all in memory is very likely to hit resource limits.
This commit adds an alternate mode for this class which avoids pulling notices until during the actual output. Instead of pre-sorting and buffering all the notices, empty spaces between the other activities are filled in with notices as we're making output. This means more smaller queries spread out during operations, and less stuff kept in memory.
Callers (backupaccount action, and backupuser.php) which can stream their output pass an $outputMode param of UserActivityStream::OUTPUT_RAW, and during getString() it'll send straight to output as well as slurping the notices in this extra funky fashion.
Other callers will let it default to the OUTPUT_STRING mode, which keeps the previous behavior.
There should be a better way to do this, swapping out the stringer output for raw output more consitently.
