mirror of
https://github.com/neondatabase/neon.git
synced 2026-01-15 09:22:55 +00:00
589cf1ed21
Initially, idea was to ensure that when we come and check data availability, special service table already contains one row. So if we loose it for some reason, we will error out. Yet, to do availability check we anyway start compute first! So it doesn't really add some value, but we affect each compute start as we update at least one row in the database. Also this writes some WAL, so if timeline is close to `neon.max_cluster_size` it could prevent compute from starting up. That said, do CREATE TABLE IF NOT EXISTS + UPSERT right in the `/check_writability` handler.
46 lines
1.3 KiB
Rust
46 lines
1.3 KiB
Rust
use anyhow::{anyhow, Result};
|
|
use tokio_postgres::NoTls;
|
|
use tracing::{error, instrument};
|
|
|
|
use crate::compute::ComputeNode;
|
|
|
|
/// Update timestamp in a row in a special service table to check
|
|
/// that we can actually write some data in this particular timeline.
|
|
/// Create table if it's missing.
|
|
#[instrument(skip_all)]
|
|
pub async fn check_writability(compute: &ComputeNode) -> Result<()> {
|
|
// Connect to the database.
|
|
let (client, connection) = tokio_postgres::connect(compute.connstr.as_str(), NoTls).await?;
|
|
if client.is_closed() {
|
|
return Err(anyhow!("connection to postgres closed"));
|
|
}
|
|
|
|
// The connection object performs the actual communication with the database,
|
|
// so spawn it off to run on its own.
|
|
tokio::spawn(async move {
|
|
if let Err(e) = connection.await {
|
|
error!("connection error: {}", e);
|
|
}
|
|
});
|
|
|
|
let query = "
|
|
CREATE TABLE IF NOT EXISTS health_check (
|
|
id serial primary key,
|
|
updated_at timestamptz default now()
|
|
);
|
|
INSERT INTO health_check VALUES (1, now())
|
|
ON CONFLICT (id) DO UPDATE
|
|
SET updated_at = now();";
|
|
|
|
let result = client.simple_query(query).await?;
|
|
|
|
if result.len() != 2 {
|
|
return Err(anyhow::format_err!(
|
|
"expected 2 query results, but got {}",
|
|
result.len()
|
|
));
|
|
}
|
|
|
|
Ok(())
|
|
}
|