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fix(pgxpool): pass base context to BeforeConnect from background healthcheck #2546

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fix(pgxpool): pass base context to BeforeConnect from background healthcheck #2546

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fix(pgxpool): pass base context to BeforeConnect from background heal…
blackwell-systems Apr 30, 2026
9262a9a
fix: use context.WithoutCancel to prevent stale cancellation on pool …
blackwell-systems May 2, 2026
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4 changes: 3 additions & 1 deletion pgxpool/pool.go
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Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,7 @@ type Pool struct {
healthCheckTimer *time.Timer

healthCheckChan chan struct{}
baseCtx context.Context

acquireTracer AcquireTracer
releaseTracer ReleaseTracer
Expand Down Expand Up @@ -250,6 +251,7 @@ func NewWithConfig(ctx context.Context, config *Config) (*Pool, error) {
healthCheckPeriod: config.HealthCheckPeriod,
healthCheckChan: make(chan struct{}, 1),
closeChan: make(chan struct{}),
baseCtx: ctx,

@abrightwell abrightwell May 2, 2026

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Storing a context for reuse doesn't feel right. One concern is if it could be cancelled or carries a deadline, as all future refills would break. Removing those prior to storing would be safer, IMO:

Suggested change
baseCtx: ctx,
baseCtx: context.WithoutCancel(ctx),

https://pkg.go.dev/context#WithoutCancel

That said, I wonder if the underlying issue is an incorrect use of context, ie., request-scoped vs. application-scoped. BeforeConnect seems like the right place for per-connection context enrichment, since it runs on every connection creation, whether for warmup or refill of the pool.

@blackwell-systems blackwell-systems May 2, 2026

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Good catch, updated to context.WithoutCancel(ctx). That prevents a request-scoped context from breaking future refills while still preserving the values that BeforeConnect callbacks depend on (e.g., AWS IAM auth tokens).

On the context scope point: agreed, BeforeConnect is the right place for per-connection enrichment. The tricky part is that background healthchecks pass context.Background(), which drops all values from the original context. So users who store auth credentials in the context passed to NewWithConfig see it work on first connect but silently break on pool refill. WithoutCancel preserves the values without carrying over cancellation or deadlines.

@abrightwell abrightwell May 2, 2026

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So users who store auth credentials in the context passed to NewWithConfig see it work on first connect but silently break on pool refill.

Credentials passed through the context seems like anti-pattern. I'd argue it points to the wrong injection point entirely. If credentials are fetched in BeforeConnect, they're available on every connection attempt regardless of what triggered it.

@blackwell-systems blackwell-systems May 2, 2026

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Fair point. Fetching credentials directly in BeforeConnect is cleaner and avoids the context-propagation question entirely. That said, the current behavior (silently dropping to context.Background() on refill) is surprising regardless of how credentials are injected. Happy to adjust the approach if jackc has a preference on the design direction.

}

if t, ok := config.ConnConfig.Tracer.(AcquireTracer); ok {
Expand Down Expand Up @@ -561,7 +563,7 @@ func (p *Pool) checkMinConns() error {
stat := p.Stat()
toCreate := max(p.minConns-stat.TotalConns(), p.minIdleConns-stat.IdleConns())
if toCreate > 0 {
return p.createIdleResources(context.Background(), int(toCreate))
return p.createIdleResources(p.baseCtx, int(toCreate))
}
return nil
}
Expand Down