On Fri, Sep 12, 2025 at 9:46 AM Andres Freund wrote:
+ * It's possible that another backend starts IO on the buffer between this
+ * check and the ReadBuffersCanStartIO(nowait = false) below. In that case
+ * we will synchronously wait for the IO below, but the window for that is
+
On Thu, Sep 11, 2025 at 5:46 PM Andres Freund wrote:
> The problem leading to that is that we are currently synchronously waiting for
> IO on a buffer when AsyncReadBuffers() encounters a buffer already undergoing
> IO. If a block is read twice, that means we won't actually have enough IOs in
> fl
Hi,
In the index prefetching thread we discovered that read stream performance
suffers rather substantially when a read stream is reading blocks multiple
times within the readahead distance.
The problem leading to that is that we are currently synchronously waiting for
IO on a buffer when AsyncRe
