Обсуждение: A out of date comment of WaitForWALToBecomeAvailable
Hi,
The following comment looks out of date now. should we fix it as following?
*
- * If the record is not immediately available, the function returns false
+ * If the record is not immediately available, the function returns XLREAD_FAIL
* if we're not in standby mode. In standby mode, waits for it to become
* available.
*
..
static XLogPageReadResult
WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess, ..)
Thanks
On Fri, Jan 30, 2026 at 10:29:41AM +0800, Andy Fan wrote: > The following comment looks out of date now. should we fix it as following? Yes, the code returns XLREAD_FAIL is we cannot find a record when not in standby mode. Thanks for the report. -- Michael
Вложения
At 2026-01-30 13:13:37, "Michael Paquier" <michael@paquier.xyz> wrote:
Hi,>On Fri, Jan 30, 2026 at 10:29:41AM +0800, Andy Fan wrote:>> The following comment looks out of date now. should we fix it as following? > >Yes, the code returns XLREAD_FAIL is we cannot find a record when not >in standby mode. Thanks for the report.Thanks for double check. patch attached.
Вложения
Hi Andy, Thanks for the patch. On Fri, Jan 30, 2026 at 6:23 PM Andy Fan <zhihuifan1213@163.com> wrote: > > At 2026-01-30 13:13:37, "Michael Paquier" <michael@paquier.xyz> wrote: > > Hi, > > >On Fri, Jan 30, 2026 at 10:29:41AM +0800, Andy Fan wrote: > >> The following comment looks out of date now. should we fix it as following? > > > >Yes, the code returns XLREAD_FAIL is we cannot find a record when not > >in standby mode. Thanks for the report. > > Thanks for double check. patch attached. > WaitForWALToBecomeAvailable can also return XLREAD_WOULDBLOCK when the caller set nonblocking. The comment only talks about XLREAD_FAIL vs “waits in standby,” so it still doesn’t describe that third outcome. That omission pre-dates this patch, should we expand the comment mention the nonblocking case as well? -- Best, Xuneng
On Mon, Feb 02, 2026 at 10:37:43AM +0800, Xuneng Zhou wrote: > WaitForWALToBecomeAvailable can also return XLREAD_WOULDBLOCK when the > caller set nonblocking. The comment only talks about XLREAD_FAIL vs > “waits in standby,” so it still doesn’t describe that third outcome. > That omission pre-dates this patch, should we expand the comment > mention the nonblocking case as well? The outcome related to XLREAD_WOULDBLOCK is implied in the last sentence of the comment block standing at the top of the function, which seems OK to me. -- Michael
Вложения
Hi All, > [[PGP Signed Part:Undecided]] > On Mon, Feb 02, 2026 at 10:37:43AM +0800, Xuneng Zhou wrote: >> WaitForWALToBecomeAvailable can also return XLREAD_WOULDBLOCK when the >> caller set nonblocking. The comment only talks about XLREAD_FAIL vs >> “waits in standby,” so it still doesn’t describe that third outcome. >> That omission pre-dates this patch, should we expand the comment >> mention the nonblocking case as well? > > The outcome related to XLREAD_WOULDBLOCK is implied in the last > sentence of the comment block standing at the top of the function, > which seems OK to me. Thank you for the double check, I personally prefer to keep XLREAD_WOULDBLOCK as it it. -- Best Regards Andy Fan