Re: quoteOneName() inconsistency with quote_all_identifiers — replacement API proposed

On Mon, Nov 17, 2025 at 5:48 PM Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com> wrote:

> Hi Hackers,
>
> == Background ==
>
> While reviewing a patch, I noticed that quoteOneName() duplicates the
> logic of quote_identifier() for adding double quotes to identifiers. The
> main difference is that quoteOneName() does *not* honor the GUC
> `quote_all_identifiers`.
>
> The typical usage pattern of quoteOneName() looks like this:
>
> ```
> // Define a local buffer with size MAX_QUOTED_NAME_LEN
> // MAX_QUOTED_NAME_LEN = MAX_NAMELEN * 2 + 3 to ensure no overflow
> char attname[MAX_QUOTED_NAME_LEN];
>
> // Add quotes and copy into the stack buffer
> quoteOneName(attname, RIAttName(pk_rel,
> riinfo->pk_attnums[riinfo->nkeys - 1]));
>
> // Copy the quoted identifier into a StringInfo
> appendStringInfoString(&querybuf, attname);
> ```
>
> This pattern is expensive because:
>
> * it allocates a larger-than-necessary buffer on the stack
> * it incurs two pallocs and two data copies
>
> Looking further, the common pattern around quote_identifier() is similar:
>
> ```
> appendStringInfoString(&relations, quote_identifier(relname));
> ```
>
> This also incurs two pallocs and two copies: quote_identifier() allocates
> a temporary buffer and copies the quoted identifier into it, and then
> appendStringInfoString() may allocate and copy again.
>
> == Idea ==
>
> I'd like to propose introducing `appendStringInfoIdentifier()`, which adds
> the quoting logic directly to StringInfo. The goals are:
>
> * eventually deprecate quoteOneName() — I'm not aware of a reason why it
> should ignore the GUC `quote_all_identifiers`
> * simplify the usage patterns for quoting identifiers
> * avoid unnecessary intermediate buffers, pallocs, and data copies
>
> == About the attached patch ==
>
> Attached v1 is not intended to be the final version — it is mainly to
> demonstrate the idea and get feedback on the design direction.
>
> * 0001 implements `appendStringInfoIdentifier()` and uses it in a few
> places
> * 0002 switches ri_triggers.c to use it, resolving a complicated usage
> pattern and showing a path toward removing quoteOneName()
>
> Comments and suggestions on the overall direction would be very welcome.
>
>
CF entry added: https://commitfest.postgresql.org/patch/6240/. And here
comes the v2 patch set.

Best regards,
Chao Li (Evan)
---------------------
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https://www.highgo.com/