zjw1111 commented on code in PR #199:
URL: https://github.com/apache/paimon-cpp/pull/199#discussion_r3774459946
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src/paimon/core/realtime/realtime_context.cpp:
##########
@@ -105,6 +127,79 @@ class RealtimeContext::Impl {
return result;
}
+ Result<std::string> PinReadView(const RealtimePartitionBucketView& view,
int64_t ttl_millis) {
+ if (!view.indexer || !view.read_view) {
+ return Status::Invalid("cannot pin an incomplete real-time read
view");
+ }
+ if (ttl_millis <= 0) {
+ return Status::Invalid("real-time read-view TTL must be greater
than zero");
+ }
+ const auto now = std::chrono::steady_clock::now();
+ const auto ttl = std::chrono::milliseconds(ttl_millis);
+ if (ttl > std::chrono::duration_cast<std::chrono::milliseconds>(
+ std::chrono::steady_clock::time_point::max() - now)) {
+ return Status::Invalid("real-time read-view TTL is too large");
+ }
+
+ while (true) {
+ std::string opaque_ticket;
+ if (!UUID::Generate(&opaque_ticket)) {
+ return Status::IOError("failed to generate a real-time
read-view ticket");
+ }
+ {
+ std::lock_guard<std::mutex> lock(read_views_mutex_);
+ bool inserted =
+ pinned_read_views_.emplace(opaque_ticket,
PinnedReadView{view, now + ttl})
+ .second;
+ if (!inserted) {
+ continue;
+ }
+ }
+ read_views_cv_.notify_all();
+ return opaque_ticket;
+ }
+ }
+
+ Result<RealtimePartitionBucketView> ResolveReadView(const std::string&
opaque_ticket) {
+ bool expired = false;
+ {
+ std::lock_guard<std::mutex> lock(read_views_mutex_);
+ auto iter = pinned_read_views_.find(opaque_ticket);
+ if (iter == pinned_read_views_.end()) {
+ return Status::Invalid("real-time read-view ticket does not
exist or has expired");
+ }
+ if (iter->second.expire_at <= std::chrono::steady_clock::now()) {
+
read_view_release_queue_.push_back(std::move(iter->second.view));
+ pinned_read_views_.erase(iter);
+ expired = true;
+ } else {
+ return iter->second.view;
Review Comment:
Resolving the ticket does not claim or remove it atomically. Two threads
calling `CreateReader` for the same `RealtimeSplit` can both return the view
here before either reaches `ReleaseReadView`, so both can create readers
despite the documented single-use contract. Please make ticket
acquisition/consumption atomic (for example, with an available/claimed state
that is rolled back when reader creation fails) and add concurrent coverage.
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