IS JSON predicate support for domain base type as JSON/JSONB/BYTEA/TEXT
hi.
src/backend/executor/execExpr.c
case T_JsonIsPredicate:
{
JsonIsPredicate *pred = (JsonIsPredicate *) node;
ExecInitExprRec((Expr *) pred->expr, state, resv, resnull);
scratch.opcode = EEOP_IS_JSON;
scratch.d.is_json.pred = pred;
ExprEvalPushStep(state, &scratch);
break;
}
gram.y:
a_expr IS json_predicate_type_constraint
the above shows the a_expr will be transformed and then evaluated.
The exprType type of a_expr as domain should work just fine.
The attached patch implements this, and it seems to be quite straightforward.
(extensive regress tests added)
CREATE DOMAIN jd1 AS JSON CHECK ((VALUE ->'a')::text <> '3');
CREATE DOMAIN jd2 AS JSONB CHECK ((VALUE ->'a') = '1'::jsonb);
CREATE DOMAIN jd4 AS bytea CHECK (VALUE <> '\x61');
SELECT NULL::jd1 IS JSON;
SELECT NULL::jd2 IS JSON;
SELECT NULL::jd4 IS JSON;
in the master, the above 3 IS JSON would return error,
with the attached patch, it will return NULL.
I checked the discussion links [1]https://git.postgresql.org/cgit/postgresql.git/commit/?id=6ee30209a6f161d0a267a33f090c70c579c87c00, but couldn’t find the reason domains aren’t
supported. I guess at that time, we didn't think about this issue.
[1]: https://git.postgresql.org/cgit/postgresql.git/commit/?id=6ee30209a6f161d0a267a33f090c70c579c87c00
Attachments:
v1-0001-IS-JSON-predicate-work-with-domain-type.patchtext/x-patch; charset=US-ASCII; name=v1-0001-IS-JSON-predicate-work-with-domain-type.patchDownload+346-13
jian he <jian.universality@gmail.com> writes:
[ v1-0001-IS-JSON-predicate-work-with-domain-type.patch ]
This looks like a large patch with a small patch struggling to
get out of it. Why didn't you simply do
- *exprtype = exprType(expr);
+ *exprtype = getBaseType(exprType(expr));in transformJsonParseArg?
regards, tom lane
On Wed, Nov 19, 2025 at 1:01 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
jian he <jian.universality@gmail.com> writes:
[ v1-0001-IS-JSON-predicate-work-with-domain-type.patch ]
This looks like a large patch with a small patch struggling to
get out of it. Why didn't you simply do- *exprtype = exprType(expr); + *exprtype = getBaseType(exprType(expr));in transformJsonParseArg?
yech.
While at it, I added parser_errposition to the transformJsonIsPredicate ereport.
errmsg("cannot use type %s in IS JSON predicate",
format_type_be(exprtype))
we don't need to worry about exprtype as InvalidOid, because
transformJsonParseArg (exprType(expr)) would fail already in that case.
Attachments:
v2-0001-IS-JSON-predicate-work-with-domain-type.patchtext/x-patch; charset=US-ASCII; name=v2-0001-IS-JSON-predicate-work-with-domain-type.patchDownload+356-10
Hi.
The regression test was very verbose; I removed some of it.
Also polished function ExecEvalJsonIsPredicate a little bit.
Attachments:
v3-0001-IS-JSON-predicate-work-with-domain-type.patchtext/x-patch; charset=US-ASCII; name=v3-0001-IS-JSON-predicate-work-with-domain-type.patchDownload+287-16
On 2026-03-12 Th 11:55 PM, jian he wrote:
Hi.
The regression test was very verbose; I removed some of it.
Also polished function ExecEvalJsonIsPredicate a little bit.
Here's a v4. I changed resultBaseType to exprBaseType - I think it's
clearer. I also trimmed the tests a bit more, and dropped the new
objects after testing them. The error message now shows the domain name
rather than the underlying base type. I think that's more useful.
cheers
andrew
--
Andrew Dunstan
EDB: https://www.enterprisedb.com
Attachments:
v4-0001-Allow-IS-JSON-predicate-to-work-with-domain-types.patchtext/x-patch; charset=UTF-8; name=v4-0001-Allow-IS-JSON-predicate-to-work-with-domain-types.patchDownload+105-18
On Fri, 13 Mar 2026 at 17:30, Andrew Dunstan <andrew@dunslane.net> wrote:
On 2026-03-12 Th 11:55 PM, jian he wrote:
Hi.
The regression test was very verbose; I removed some of it.
Also polished function ExecEvalJsonIsPredicate a little bit.Here's a v4. I changed resultBaseType to exprBaseType - I think it's
clearer. I also trimmed the tests a bit more, and dropped the new
objects after testing them. The error message now shows the domain name
rather than the underlying base type. I think that's more useful.
Hi!
V4 looks good. The only thing that I cannot explain is removing the
`exprtype` variable inside ExecEvalJsonIsPredicate. We can just change
its declaration to
exprtype = pred->exprBaseType if i'm not mistaken?
Anyway, LGTM
--
Andrew Dunstan
EDB: https://www.enterprisedb.com
--
Best regards,
Kirill Reshke
On 2026-03-13 Fr 9:16 AM, Kirill Reshke wrote:
On Fri, 13 Mar 2026 at 17:30, Andrew Dunstan <andrew@dunslane.net> wrote:
On 2026-03-12 Th 11:55 PM, jian he wrote:
Hi.
The regression test was very verbose; I removed some of it.
Also polished function ExecEvalJsonIsPredicate a little bit.Here's a v4. I changed resultBaseType to exprBaseType - I think it's
clearer. I also trimmed the tests a bit more, and dropped the new
objects after testing them. The error message now shows the domain name
rather than the underlying base type. I think that's more useful.Hi!
V4 looks good. The only thing that I cannot explain is removing the
`exprtype` variable inside ExecEvalJsonIsPredicate. We can just change
its declaration toexprtype = pred->exprBaseType if i'm not mistaken?
Yeah, we can do that.
Anyway, LGTM
Thanks for reviewing.
cheers
andrew
--
Andrew Dunstan
EDB: https://www.enterprisedb.com
On 2026-03-13 Fr 9:47 AM, Andrew Dunstan wrote:
On 2026-03-13 Fr 9:16 AM, Kirill Reshke wrote:
On Fri, 13 Mar 2026 at 17:30, Andrew Dunstan <andrew@dunslane.net>
wrote:On 2026-03-12 Th 11:55 PM, jian he wrote:
Hi.
The regression test was very verbose; I removed some of it.
Also polished function ExecEvalJsonIsPredicate a little bit.Here's a v4. I changed resultBaseType to exprBaseType - I think it's
clearer. I also trimmed the tests a bit more, and dropped the new
objects after testing them. The error message now shows the domain
name
rather than the underlying base type. I think that's more useful.Hi!
V4 looks good. The only thing that I cannot explain is removing the
`exprtype` variable inside ExecEvalJsonIsPredicate. We can just change
its declaration toexprtype = pred->exprBaseType if i'm not mistaken?
Yeah, we can do that.
Anyway, LGTM
Committed with that change.
cheers
andrew
--
Andrew Dunstan
EDB: https://www.enterprisedb.com