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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2022-09-27 11:47:12 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2022-09-27 11:47:12 -0400 |
| commit | 385366426511399a91da327c0f04765bbcfd5322 (patch) | |
| tree | bb6851d6157032806a9df6ab23a4242b548bb378 /src/backend/utils/misc/guc_funcs.c | |
| parent | 4148c8b3daf95ca308f055e103f6ee82e25b8f99 (diff) | |
| download | postgresql-385366426511399a91da327c0f04765bbcfd5322.tar.gz postgresql-385366426511399a91da327c0f04765bbcfd5322.zip | |
Introduce GUC_NO_RESET flag.
Previously, the transaction-property GUCs such as transaction_isolation
could be reset after starting a transaction, because we marked them
as GUC_NO_RESET_ALL but still allowed a targeted RESET. That leads to
assertion failures or worse, because those properties aren't supposed
to change after we've acquired a transaction snapshot.
There are some NO_RESET_ALL variables for which RESET is okay, so
we can't just redefine the semantics of that flag. Instead introduce
a separate GUC_NO_RESET flag. Mark "seed", as well as the transaction
property GUCs, as GUC_NO_RESET.
We have to disallow GUC_ACTION_SAVE as well as straight RESET, because
otherwise a function having a "SET transaction_isolation" clause can
still break things: the end-of-function restore action is equivalent
to a RESET.
No back-patch, as it's conceivable that someone is doing something
this patch will forbid (like resetting one of these GUCs at transaction
start, or "CREATE FUNCTION ... SET transaction_read_only = 1") and not
running into problems with it today. Given how long we've had this
issue and not noticed, the side effects in non-assert builds can't be
too serious.
Per bug #17385 from Andrew Bille.
Masahiko Sawada
Discussion: https://postgr.es/m/17385-9ee529fb091f0ce5@postgresql.org
Diffstat (limited to 'src/backend/utils/misc/guc_funcs.c')
| -rw-r--r-- | src/backend/utils/misc/guc_funcs.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/src/backend/utils/misc/guc_funcs.c b/src/backend/utils/misc/guc_funcs.c index 3d2df18659b..ffc71726f91 100644 --- a/src/backend/utils/misc/guc_funcs.c +++ b/src/backend/utils/misc/guc_funcs.c @@ -141,9 +141,6 @@ ExecSetVariableStmt(VariableSetStmt *stmt, bool isTopLevel) WarnNoTransactionBlock(isTopLevel, "SET LOCAL"); /* fall through */ case VAR_RESET: - if (strcmp(stmt->name, "transaction_isolation") == 0) - WarnNoTransactionBlock(isTopLevel, "RESET TRANSACTION"); - (void) set_config_option(stmt->name, NULL, (superuser() ? PGC_SUSET : PGC_USERSET), @@ -539,7 +536,7 @@ ShowAllGUCConfig(DestReceiver *dest) Datum pg_settings_get_flags(PG_FUNCTION_ARGS) { -#define MAX_GUC_FLAGS 5 +#define MAX_GUC_FLAGS 6 char *varname = TextDatumGetCString(PG_GETARG_DATUM(0)); struct config_generic *record; int cnt = 0; @@ -554,6 +551,8 @@ pg_settings_get_flags(PG_FUNCTION_ARGS) if (record->flags & GUC_EXPLAIN) flags[cnt++] = CStringGetTextDatum("EXPLAIN"); + if (record->flags & GUC_NO_RESET) + flags[cnt++] = CStringGetTextDatum("NO_RESET"); if (record->flags & GUC_NO_RESET_ALL) flags[cnt++] = CStringGetTextDatum("NO_RESET_ALL"); if (record->flags & GUC_NO_SHOW_ALL) |