Re: missing PG_IO_ALIGN_SIZE uses

Peter Eisentraut <peter@eisentraut.org>

From: Peter Eisentraut <peter@eisentraut.org>
To: Chao Li <li.evan.chao@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2025-12-08T14:23:06Z
Lists: pgsql-hackers
On 02.12.25 02:11, Chao Li wrote:
>> <0001-Use-PG_IO_ALIGN_SIZE-for-aligning-WAL-buffers.patch><0002-Use-PGAlignedXLogBlock-in-BootStrapXLOG.patch><0003-pg_test_fsync-Align-test-data-using-PGAlignedXLogBlo.patch>
> Overall the patch looks good to me:

I have committed these all as one patch.  Initially I thought the first 
patch might be worth backpatching, but it seems that's not needed.

> 0001 fixes two overlooked alignment to PG_IO_ALIGN_SIZE
> 0002 switches BootStrapXLOG to use PGAlignedXLogBlock, which is aligned to PG_IO_ALIGN_SIZE
> 0003 does the same for pg_test_fsync
> 
> My only nit comment is in 0002:
> ```
> -	memset(page, 0, XLOG_BLCKSZ);
> +	memset(&buffer, 0, sizeof buffer);
> ```
> 
> I know “sizeof” is an operator instead of a function, “sizeof buffer” is grammatically correct. However, most of places do “sizeof(buffer)”, so unless we want to prompt the syntax of “sizeof buffer” (without the braces), it’s better to keep a consistent syntax.

The style without parentheses is not non-existent in PostgreSQL code, so 
I think we can use it when appropriate.




Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. Use PGAlignedXLogBlock for some code simplification

  2. Introduce PG_IO_ALIGN_SIZE and align all I/O buffers.