FEATURE: new rake task to update first_post_created_at column
The not-equal operator (`<>`) in PostgreSQL does not compare values
with NULL. We should instead use `IS DISTINCT FROM` when comparing
values with NULL.
* PERF: Dematerialize topic_reply_count
It's only ever used for trust level promotions that run daily, or compared to 0. We don't need to track it on every post creation.
* UX: Add symbol in TL3 report if topic reply count is capped
* DEV: Drop user_stats.topic_reply_count column
This ensures we only update last_posted_at which is user facing for non messages
and non whispers.
We still update this date for secure categories, we do not revert it for
deleted posts.
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
Introduce new patterns for direct sql that are safe and fast.
MiniSql is not prone to memory bloat that can happen with direct PG usage.
It also has an extremely fast materializer and very a convenient API
- DB.exec(sql, *params) => runs sql returns row count
- DB.query(sql, *params) => runs sql returns usable objects (not a hash)
- DB.query_hash(sql, *params) => runs sql returns an array of hashes
- DB.query_single(sql, *params) => runs sql and returns a flat one dimensional array
- DB.build(sql) => returns a sql builder
See more at: https://github.com/discourse/mini_sql
