From 18ccffba07b1301ad8cbd1feaf3820d96ef9bfbb Mon Sep 17 00:00:00 2001 From: Srinath Reddy Sadipiralla Date: Fri, 3 Apr 2026 20:53:56 +0530 Subject: [PATCH v53 5/7] Check for transaction block early in ExecRepack Currently, executing REPACK (CONCURRENTLY) without a table name inside a transaction block throws the error "REPACK CONCURRENTLY requires explicit table name" instead of the expected transaction block error. This occurs because ExecRepack() validates the parsed options and missing relation before verifying the transaction state. This behavior is inconsistent with other utility commands like VACUUM ,REINDEX, etc; which invoke PreventInTransactionBlock() at the very start of their execution to properly reject execution inside user transactions before validating targets. Add PreventInTransactionBlock to the top of ExecRepack() to enforce the transaction block restriction early. This prevents the user from fixing a missing table error only to immediately hit a transaction block error, and also ensures consistency with rest of the commands. Author: Srinath Reddy Sadipiralla --- src/backend/commands/repack.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index f2759cdbef1..8d9b2b2e370 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -279,6 +279,21 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) /* Determine the lock mode to use. */ lockmode = RepackLockLevel((params.options & CLUOPT_CONCURRENT) != 0); + if ((params.options & CLUOPT_CONCURRENT) != 0) + { + /* + * Make sure we're not in a transaction block. + * + * The reason is that repack_setup_logical_decoding() could wait + * indefinitely for our XID to complete. (The deadlock detector would + * not recognize it because we'd be waiting for ourselves, i.e. no + * real lock conflict.) It would be possible to run in a transaction + * block if we had no XID, but this restriction is simpler for users + * to understand and we don't lose any functionality. + */ + PreventInTransactionBlock(isTopLevel, "REPACK (CONCURRENTLY)"); + } + /* * If a single relation is specified, process it and we're done ... unless * the relation is a partitioned table, in which case we fall through. @@ -511,19 +526,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid, * replica index OID. */ if (concurrent) - { - /* - * Make sure we're not in a transaction block. - * - * The reason is that repack_setup_logical_decoding() could deadlock - * if there's an XID already assigned. It would be possible to run in - * a transaction block if we had no XID, but this restriction is - * simpler for users to understand and we don't lose anything. - */ - PreventInTransactionBlock(isTopLevel, "REPACK (CONCURRENTLY)"); - check_repack_concurrently_requirements(OldHeap, &ident_idx); - } /* Check for user-requested abort. */ CHECK_FOR_INTERRUPTS(); -- 2.47.3