joao-r-reis commented on code in PR #1875:
URL:
https://github.com/apache/cassandra-gocql-driver/pull/1875#discussion_r2079857332
##########
query_executor.go:
##########
@@ -89,14 +89,18 @@ func (q *queryExecutor) executeQuery(qry ExecutableQuery)
(*Iter, error) {
// check if the host id is specified for the query,
// if it is, the query should be executed at the corresponding host.
if hostID := qry.GetHostID(); hostID != "" {
+ pool, ok := q.pool.getPoolByHostID(hostID)
+ if !ok || !pool.host.IsUp() {
+ return nil, ErrNoConnections
+ }
+ host := pool.host
hostIter = func() SelectedHost {
- pool, ok := q.pool.getPoolByHostID(hostID)
- // if the specified host is down
- // we return nil to avoid endless query execution in
queryExecutor.do()
- if !ok || !pool.host.IsUp() {
- return nil
+ if host != nil {
Review Comment:
To ensure this `hostIter` can be safely called concurrently I think we
should make the outer variable an `int` and then use `atomic.CompareAndSwap` in
this `if`
```
returnedHostOnce := 0
hostIter = func() SelectedHost {
if atomic.CompareAndSwapInt32(&returnedHostOnce, 0, 1) {
return return (*selectedHost)(host)
}
return nil
}
```
##########
query_executor.go:
##########
@@ -89,14 +89,18 @@ func (q *queryExecutor) executeQuery(qry ExecutableQuery)
(*Iter, error) {
// check if the host id is specified for the query,
// if it is, the query should be executed at the corresponding host.
if hostID := qry.GetHostID(); hostID != "" {
+ pool, ok := q.pool.getPoolByHostID(hostID)
+ if !ok || !pool.host.IsUp() {
Review Comment:
I don't think we need this now that we return `nil` after the first
execution since this check is already being done in the query executor. We
needed this before because we needed a way to prevent the `hostIter` from
returning the same unresponsive host over and over again.
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