pgjdbc/pgjdbc GitHub issues and pull requests (mirror)
help / color / mirror / Atom feedFrom: davecramer (@davecramer) <[email protected]>
To: pgjdbc/pgjdbc <[email protected]>
Subject: [pgjdbc/pgjdbc] PR #4074: Use NIO
Date: Fri, 15 May 2026 20:28:18 +0000
Message-ID: <[email protected]> (raw)
docs: add full NIO refactor design document
Outlines the architecture for replacing PGStream's blocking I/O with SocketChannel + ByteBuffer + Selector. This enables true async notification detection and eliminates socket sharing races.
Key decisions:
- Channel always non-blocking, blocking via Selector.select()
- Selector.selectNow() for thread-safe async readability checks
- SSLEngine for NIO-compatible SSL
- Backward compatibility with existing PGStream API
wip: NIO full refactor - NIOInputStream/NIOOutputStream and PGStream SocketChannel scaffolding
Adds NIOInputStream (Selector-based blocking reads via ByteBuffer) and NIOOutputStream (buffered channel writes). PGStream creates a SocketChannel but still uses VisibleBufferedInputStream for reads — next step is to replace all reads with NIOInputStream.
The channel is created in non-blocking mode for Selector compatibility. The full refactor requires replacing pgInput usage throughout PGStream with NIOInputStream to eliminate the InputStream/blocking mode conflict.
wip: NIO full refactor - NIOInputStream/NIOOutputStream and PGStream SocketChannel scaffolding
Adds NIOInputStream (Selector-based blocking reads via ByteBuffer) and NIOOutputStream (buffered channel writes). PGStream creates a SocketChannel but still uses VisibleBufferedInputStream for reads — next step is to replace all reads with NIOInputStream.
The channel is created in non-blocking mode for Selector compatibility. The full refactor requires replacing pgInput usage throughout PGStream with NIOInputStream to eliminate the InputStream/blocking mode conflict.
wip: PGStream uses NIOInputStream/NIOOutputStream in non-SSL mode
changeSocket now creates NIOInputStream (Selector-based) and NIOOutputStream (channel-based) when a SocketChannel is available. Falls back to traditional InputStream/OutputStream for SSL connections.
pgInput is now nullable — next step is to update all read methods in PGStream to delegate to nioInput when in NIO mode.
feat: full NIO refactor - PGStream uses SocketChannel + Selector after setup
PGStream now creates a SocketChannel-backed socket and switches to NIO mode after connection setup (including SSL negotiation) completes:
- createSocket() uses SocketChannel.open() for default socket factory
- Channel stays in blocking mode during connection setup for SSL compat
- enableNIO() called from PgConnection constructor switches to non-blocking
- NIOInputStream uses Selector.select() for blocking reads via ByteBuffer
- NIOOutputStream writes to channel via ByteBuffer on flush
- VisibleBufferedInputStream wraps NIOInputStream (existing API unchanged)
- SSL connections fall back to traditional InputStream (no NIO)
Key benefit: NIOInputStream.isReadable() uses Selector.selectNow() which is thread-safe — a background NotificationPoller can check for incoming async data without reading from the socket or conflicting with the main thread's reads.
All 26 pipeline tests pass.
feat: add NotificationPoller for async LISTEN/NOTIFY detection
Background daemon thread that uses NIOInputStream.isReadable() (Selector.selectNow()) to detect incoming async data without reading from the socket. Thread-safe — no socket sharing conflicts.
When data is detected, sets a flag. getNotifications() checks the flag and processes any pending NotificationResponse or ParameterStatus messages before returning.
- NotificationPoller started in enableNIO() (after connection setup)
- Shut down on connection close/abort
- Only active for non-SSL connections (SSL falls back to polling in getNotifications via hasMessagePending)
- 100ms poll interval when idle, 10ms spin when waiting for main thread
All 26 pipeline tests pass.
fix: resolve checkstyle and checker-framework violations
- Remove unused SelectionKey/Selector imports from PGStream
- Fix PGNotification import ordering in QueryExecutorImpl
- Use local variable for nullable notificationPoller dereference
- Use local variable for nullable nioChannel in enableNIO()
chore: remove development artifacts and binary blobs from repo
Remove files that should not be in the PR:
- 30MB heap dump (.hprof)
- Development scripts and design documents
- Generated pom.xml
- IDE settings (.kiro/)
fix: address NIO review feedback
- NIOOutputStream: replace Thread.yield() spin-loop with Selector OP_WRITE wait when OS send buffer is full
- NotificationPoller: use Selector.select(timeout) for efficient blocking instead of Thread.sleep(100) polling loop
- processPolledNotifications: acquire main lock to prevent concurrent socket access with query execution
- PGStream.close: explicitly close NIOInputStream and its Selector
- Add NIOInputStream.waitForData(timeout) for blocking select
fix: replace Thread.sleep spin with Object.wait/notify in NotificationPoller
Use wait/notify for the dataAvailable flag instead of Thread.sleep(10) polling. The poller now parks efficiently until clearDataAvailable() is called by the main thread, eliminating unnecessary wakeups.
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