[YSQL] Include DETAIL in duplicate key unique violation error for PG compatibility by jaydeep-pipaliya · Pull Request #31031 · yugabyte/yugabyte-db

jaydeep-pipaliya · 2026-04-09T11:59:50Z

Problem

PostgreSQL emits a DETAIL line for unique constraint violations:

ERROR:  duplicate key value violates unique constraint "err_pkey"
DETAIL: Key (k)=(1) already exists.

YugabyteDB only emits the ERROR line without DETAIL:

ERROR:  duplicate key value violates unique constraint "err_pkey"

This breaks PostgreSQL compatibility for applications and ORMs that parse error details to extract the conflicting key info (e.g., Prisma, SQLAlchemy, ActiveRecord).

Root Cause

In src/postgres/src/backend/utils/misc/pg_yb_utils.c, GetStatusMsgAndArgumentsByCode handles ERRCODE_UNIQUE_VIOLATION at line 960–965 by setting the error message and constraint name, but never populates detail_buf — so the DETAIL field is always empty.

Other error codes in the same switch statement (e.g., ERRCODE_YB_TXN_ABORTED at line 966, ERRCODE_YB_TXN_CONFLICT at line 975) already follow the pattern of passing the DocDB status message as the DETAIL field.

Fix

Pass the DocDB status message (status_msg) as detail_buf for ERRCODE_UNIQUE_VIOLATION, following the same pattern already established by other error codes in the same function:

case ERRCODE_UNIQUE_VIOLATION:
    *msg_buf = "duplicate key value violates unique constraint \"%s\"";
    *msg_nargs = 1;
    *msg_args = (const char **) palloc(sizeof(const char *));
    (*msg_args)[0] = FetchUniqueConstraintName(YBCStatusRelationOid(s));

    if (status_msg && status_msg[0] != '\0')
    {
        *detail_buf = status_msg;
        *detail_nargs = status_nargs;
        *detail_args = status_args;
    }
    break;

Testing

This change only affects the error output formatting — it adds the DETAIL line to unique violation errors without changing any error handling logic or control flow. The guard status_msg[0] != '\0' ensures we only add DETAIL when DocDB provides a non-empty message.

Phorge: D52066

PostgreSQL emits a DETAIL line for unique constraint violations: ERROR: duplicate key value violates unique constraint "err_pkey" DETAIL: Key (k)=(1) already exists. YugabyteDB was missing this DETAIL line because the ERRCODE_UNIQUE_VIOLATION case in GetStatusMsgAndArgumentsByCode only set the error message but never populated detail_buf. Pass the DocDB status message as the DETAIL field, following the same pattern already used by ERRCODE_YB_TXN_ABORTED and ERRCODE_YB_TXN_CONFLICT. Fixes yugabyte#30992

CLAassistant · 2026-04-09T11:59:58Z

All committers have signed the CLA.

gemini-code-assist

Code Review

This pull request modifies pg_yb_utils.c to improve PostgreSQL compatibility for unique violation error messages. It now includes the original DocDB status message as a DETAIL field when handling ERRCODE_YB_UNIQUE_VIOLATION, aligning with PostgreSQL's practice of providing detailed key information for unique constraint errors. There is no feedback to provide.

If the DocDB status message contains % characters (e.g., from column names like 'discount%'), passing it directly as a format string could cause a crash or memory corruption. Use '%s' as the format string and pass status_msg as the sole argument instead.

netlify · 2026-04-11T04:58:38Z

✅ Deploy Preview for infallible-bardeen-164bc9 ready!

Built without sensitive environment variables

Name	Link
🔨 Latest commit	`5ca956c`
🔍 Latest deploy log	https://app.netlify.com/projects/infallible-bardeen-164bc9/deploys/69d9d4ad3d45de0008551fa6
😎 Deploy Preview	https://deploy-preview-31031--infallible-bardeen-164bc9.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

To edit notification comments on pull requests, go to your Netlify project configuration.

iSignal · 2026-04-15T00:34:53Z

trigger jenkins

hari90 · 2026-04-15T00:35:12Z

Phorge diff synced: D52066
Commit: 5ca956c6

Jenkins build has been triggered. Results will be posted here once it completes.

JenkinsBot

hari90 · 2026-04-15T03:47:46Z

❌ Jenkins build for commit 5ca956c6: Fail

Exceptions:

'Multi-Build Test Failures' failed. CSI-Checks (http://csiweb.dev.yugabyte.com/D52066/#CSI-Checks)
'Too Many Test Failures Per Build' failed. CSI-Checks (http://csiweb.dev.yugabyte.com/D52066/#CSI-Checks)
Passed: 10

🚫 Failed Landing Requirements

Checking for failures in 3+ build flavors
Multi-Build failures:

org.yb.pgsql.TestPgRegressBufferingWithSQLErrors - testPgRegressBufferingWithSQLErrors
org.yb.pgsql.TestPgRegressInsertOnConflictBatch1 - schedule
org.yb.pgsql.TestPgRegressInsertOnConflictBatch2 - schedule
org.yb.pgsql.TestPgRegressLargeTable - testPgRegressLargeTable
org.yb.pgsql.TestPgRegressPgConstraints - schedule
org.yb.pgsql.TestPgRegressPgDml - schedule
org.yb.pgsql.TestPgRegressPgGenerated - schedule
org.yb.pgsql.TestPgRegressPgMiscIndependent - testPgRegressPgMiscIndependent
org.yb.pgsql.TestPgRegressThirdPartyExtensionsPgStatMonitor - schedule
org.yb.pgsql.TestPgRegressTypesNumeric - schedule
org.yb.pgsql.TestPgRegressUpdateOptimized - schedule

Checking test failure count per build versus limit of 20 (0 on mac).

Build	Failures	Status
D52066-mac14-clang-release #1	0	Okay
D52066-alma9-clang21-asan #1	42	FAILURE
D52066-alma8-clang21-tsan #1	31	FAILURE
D52066-alma8-gcc12-fastdebug #1	41	FAILURE
D52066-alma8-clang21-release #1	39	FAILURE
D52066-arm-mac14-clang-release #1	0	Okay
D52066-ubuntu22.04-clang21-debug #1	0	Okay
D52066-arm-alma8-clang21-release #1	41	FAILURE

🔨 DB Build/Test Job Summary

Build	Total	Passed	Failed	Failed After Retries
D52066-mac14-clang-release	2	2	0	0
D52066-alma9-clang21-asan	11782	11006	47	42
D52066-alma8-clang21-tsan	11694	10027	40	31
D52066-alma8-gcc12-fastdebug	11905	11403	44	41
D52066-alma8-clang21-release	11166	10703	44	39
D52066-arm-mac14-clang-release	17	17	0	0
D52066-ubuntu22.04-clang21-debug	2	2	0	0
D52066-arm-alma8-clang21-release	11164	10697	45	41

Full status

JenkinsBot

…e, not key info The status_msg passed to GetStatusMsgAndArgumentsByCode for ERRCODE_UNIQUE_VIOLATION is the SQLSTATE code string '23505', not a human-readable error detail. This is because pg_perform_future.cc replaces the original DocDB response (which contains 'Duplicate key found in primary key or unique index') with a synthetic Status built from PgsqlError(YB_PG_UNIQUE_VIOLATION), whose Message() is just the SQLSTATE encoding. Using this as DETAIL produced 'DETAIL: 23505' in error output, which broke 30+ pgregress test suites that assert on exact error messages. Remove the DETAIL addition. Generating the proper PostgreSQL-style DETAIL ('Key (col)=(val) already exists.') requires DocDB to propagate the conflicting key information through the error path.

jaydeep-pipaliya · 2026-04-23T04:45:30Z

Root cause of CI failure

I traced the error path end-to-end and found that status_msg for ERRCODE_UNIQUE_VIOLATION is not a human-readable error detail — it's the SQLSTATE code "23505".

Why: In pg_perform_future.cc, when a PGSQL_STATUS_DUPLICATE_KEY_ERROR response comes back from DocDB, the original status (which contains the actual message "Duplicate key found in primary key or unique index") is replaced with a synthetic Status:

static const auto duplicate_key_status =
    STATUS(AlreadyPresent, PgsqlError(YBPgErrorCode::YB_PG_UNIQUE_VIOLATION));

This Status is constructed via Status(code, file, line, StatusErrorCode& error) which calls error.Message() → PgsqlErrorTag::ToMessage(value) → ToString(YBPgErrorCode), which returns the 5-char SQLSTATE encoding "23505".

So my previous DETAIL addition was producing DETAIL: 23505 — which is why 30+ pgregress test suites failed.

Fix: Removed the DETAIL addition. Added a comment explaining why DETAIL can't be added via this path and that it would require DocDB to propagate conflicting key information. The constraint name in the ERROR message (from FetchUniqueConstraintName) is still included — that part works correctly.

gemini-code-assist Bot reviewed Apr 9, 2026

View reviewed changes

jaydeep-pipaliya mentioned this pull request Apr 11, 2026

[DocDB] Add /api/v1/tasks JSON endpoint for Master UI tasks page #31042

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[YSQL] Include DETAIL in duplicate key unique violation error for PG compatibility#31031

[YSQL] Include DETAIL in duplicate key unique violation error for PG compatibility#31031
jaydeep-pipaliya wants to merge 3 commits intoyugabyte:masterfrom
jaydeep-pipaliya:fix/unique-violation-detail-message

jaydeep-pipaliya commented Apr 9, 2026 •

edited by hari90

Loading

Uh oh!

CLAassistant commented Apr 9, 2026 •

edited

Loading

Uh oh!

gemini-code-assist Bot left a comment

Uh oh!

netlify Bot commented Apr 11, 2026

Uh oh!

iSignal commented Apr 15, 2026

Uh oh!

hari90 commented Apr 15, 2026

Uh oh!

hari90 commented Apr 15, 2026

Uh oh!

jaydeep-pipaliya commented Apr 23, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Conversation

jaydeep-pipaliya commented Apr 9, 2026 • edited by hari90 Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Problem

Root Cause

Fix

Testing

Uh oh!

CLAassistant commented Apr 9, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

gemini-code-assist Bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

netlify Bot commented Apr 11, 2026

✅ Deploy Preview for infallible-bardeen-164bc9 ready!

Uh oh!

iSignal commented Apr 15, 2026

Uh oh!

hari90 commented Apr 15, 2026

Uh oh!

hari90 commented Apr 15, 2026

🚫 Failed Landing Requirements

🔨 DB Build/Test Job Summary

Uh oh!

jaydeep-pipaliya commented Apr 23, 2026

Root cause of CI failure

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

jaydeep-pipaliya commented Apr 9, 2026 •

edited by hari90

Loading

CLAassistant commented Apr 9, 2026 •

edited

Loading