COMMIT/ROLLBACK necessarily destroys all snapshots within the session.
The original implementation of intra-procedure transactions just
cavalierly did that, ignoring the fact that this left us executing in
a rather different environment than normal. In particular, it turns
out that handling of toasted datums depends rather critically on there
being an outer ActiveSnapshot: otherwise, when SPI or the core
executor pop whatever snapshot they used and return, it's unsafe to
dereference any toasted datums that may appear in the query result.
It's possible to demonstrate "no known snapshots" and "missing chunk
number N for toast value" errors as a result of this oversight.
Historically this outer snapshot has been held by the Portal code,
and that seems like a good plan to preserve. So add infrastructure
to pquery.c to allow re-establishing the Portal-owned snapshot if it's
not there anymore, and add enough bookkeeping support that we can tell
whether it is or not.
We can't, however, just re-establish the Portal snapshot as part of
COMMIT/ROLLBACK. As in normal transaction start, acquiring the first
snapshot should wait until after SET and LOCK commands. Hence, teach
spi.c about doing this at the right time. (Note that this patch
doesn't fix the problem for any PLs that try to run intra-procedure
transactions without using SPI to execute SQL commands.)
This makes SPI's no_snapshots parameter rather a misnomer, so in HEAD,
rename that to allow_nonatomic.
replication/logical/worker.c also needs some fixes, because it wasn't
careful to hold a snapshot open around AFTER trigger execution.
That code doesn't use a Portal, which I suspect someday we're gonna
have to fix. But for now, just rearrange the order of operations.
This includes back-patching the recent addition of finish_estate()
to centralize the cleanup logic there.
This also back-patches commit
2ecfeda3e into v13, to improve the
test coverage for worker.c (it was that test that exposed that
worker.c's snapshot management is wrong).
Per bug #15990 from Andreas Wicht. Back-patch to v11 where
intra-procedure COMMIT was added.
Discussion: https://postgr.es/m/15990-
eee2ac466b11293d@postgresql.org
#include "parser/parse_func.h"
#include "parser/parse_type.h"
#include "pgstat.h"
+#include "tcop/pquery.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
if (fcinfo->isnull)
elog(ERROR, "procedure returned null record");
+ /*
+ * Ensure there's an active snapshot whilst we execute whatever's
+ * involved here. Note that this is *not* sufficient to make the
+ * world safe for TOAST pointers to be included in the returned data:
+ * the referenced data could have gone away while we didn't hold a
+ * snapshot. Hence, it's incumbent on PLs that can do COMMIT/ROLLBACK
+ * to not return TOAST pointers, unless those pointers were fetched
+ * after the last COMMIT/ROLLBACK in the procedure.
+ *
+ * XXX that is a really nasty, hard-to-test requirement. Is there a
+ * way to remove it?
+ */
+ EnsurePortalSnapshotExists();
+
td = DatumGetHeapTupleHeader(retval);
tupType = HeapTupleHeaderGetTypeId(td);
tupTypmod = HeapTupleHeaderGetTypMod(td);
/* Start the actual commit */
_SPI_current->internal_xact = true;
- /*
- * Before committing, pop all active snapshots to avoid error about
- * "snapshot %p still active".
- */
- while (ActiveSnapshotSet())
- PopActiveSnapshot();
+ /* Release snapshots associated with portals */
+ ForgetPortalSnapshots();
if (chain)
SaveTransactionCharacteristics();
/* Start the actual rollback */
_SPI_current->internal_xact = true;
+ /* Release snapshots associated with portals */
+ ForgetPortalSnapshots();
+
if (chain)
SaveTransactionCharacteristics();
uint64 my_processed = 0;
SPITupleTable *my_tuptable = NULL;
int res = 0;
+ bool allow_nonatomic = plan->no_snapshots; /* legacy API name */
bool pushed_active_snap = false;
ErrorContextCallback spierrcontext;
CachedPlan *cplan = NULL;
* In the first two cases, we can just push the snap onto the stack once
* for the whole plan list.
*
- * But if the plan has no_snapshots set to true, then don't manage
- * snapshots at all. The caller should then take care of that.
+ * Note that snapshot != InvalidSnapshot implies an atomic execution
+ * context.
*/
- if (snapshot != InvalidSnapshot && !plan->no_snapshots)
+ if (snapshot != InvalidSnapshot)
{
+ Assert(!allow_nonatomic);
if (read_only)
{
PushActiveSnapshot(snapshot);
stmt_list = cplan->stmt_list;
/*
- * In the default non-read-only case, get a new snapshot, replacing
- * any that we pushed in a previous cycle.
+ * If we weren't given a specific snapshot to use, and the statement
+ * list requires a snapshot, set that up.
*/
- if (snapshot == InvalidSnapshot && !read_only && !plan->no_snapshots)
+ if (snapshot == InvalidSnapshot &&
+ (list_length(stmt_list) > 1 ||
+ (list_length(stmt_list) == 1 &&
+ PlannedStmtRequiresSnapshot(linitial_node(PlannedStmt,
+ stmt_list)))))
{
- if (pushed_active_snap)
- PopActiveSnapshot();
- PushActiveSnapshot(GetTransactionSnapshot());
- pushed_active_snap = true;
+ /*
+ * First, ensure there's a Portal-level snapshot. This back-fills
+ * the snapshot stack in case the previous operation was a COMMIT
+ * or ROLLBACK inside a procedure or DO block. (We can't put back
+ * the Portal snapshot any sooner, or we'd break cases like doing
+ * SET or LOCK just after COMMIT.) It's enough to check once per
+ * statement list, since COMMIT/ROLLBACK/CALL/DO can't appear
+ * within a multi-statement list.
+ */
+ EnsurePortalSnapshotExists();
+
+ /*
+ * In the default non-read-only case, get a new per-statement-list
+ * snapshot, replacing any that we pushed in a previous cycle.
+ * Skip it when doing non-atomic execution, though (we rely
+ * entirely on the Portal snapshot in that case).
+ */
+ if (!read_only && !allow_nonatomic)
+ {
+ if (pushed_active_snap)
+ PopActiveSnapshot();
+ PushActiveSnapshot(GetTransactionSnapshot());
+ pushed_active_snap = true;
+ }
}
foreach(lc2, stmt_list)
_SPI_current->processed = 0;
_SPI_current->tuptable = NULL;
+ /* Check for unsupported cases. */
if (stmt->utilityStmt)
{
if (IsA(stmt->utilityStmt, CopyStmt))
/*
* If not read-only mode, advance the command counter before each
- * command and update the snapshot.
+ * command and update the snapshot. (But skip it if the snapshot
+ * isn't under our control.)
*/
- if (!read_only && !plan->no_snapshots)
+ if (!read_only && pushed_active_snap)
{
CommandCounterIncrement();
UpdateActiveSnapshotCommandId();
ProcessUtilityContext context;
/*
- * If the SPI context is atomic, or we are asked to manage
- * snapshots, then we are in an atomic execution context.
- * Conversely, to propagate a nonatomic execution context, the
- * caller must be in a nonatomic SPI context and manage
- * snapshots itself.
+ * If the SPI context is atomic, or we were not told to allow
+ * nonatomic operations, tell ProcessUtility this is an atomic
+ * execution context.
*/
- if (_SPI_current->atomic || !plan->no_snapshots)
+ if (_SPI_current->atomic || !allow_nonatomic)
context = PROCESS_UTILITY_QUERY;
else
context = PROCESS_UTILITY_QUERY_NONATOMIC;
ResultRelInfo *resultRelInfo;
RangeTblEntry *rte;
+ /*
+ * Input functions may need an active snapshot, as may AFTER triggers
+ * invoked during finish_estate. For safety, ensure an active snapshot
+ * exists throughout all our usage of the executor.
+ */
+ PushActiveSnapshot(GetTransactionSnapshot());
+
estate = CreateExecutorState();
rte = makeNode(RangeTblEntry);
return estate;
}
+/*
+ * Finish any operations related to the executor state created by
+ * create_estate_for_relation().
+ */
+static void
+finish_estate(EState *estate)
+{
+ /* Handle any queued AFTER triggers. */
+ AfterTriggerEndQuery(estate);
+
+ /* Cleanup. */
+ ExecResetTupleTable(estate->es_tupleTable, false);
+ FreeExecutorState(estate);
+ PopActiveSnapshot();
+}
+
/*
* Executes default values for columns for which we can't map to remote
* relation columns.
RelationGetDescr(rel->localrel),
&TTSOpsVirtual);
- /* Input functions may need an active snapshot, so get one */
- PushActiveSnapshot(GetTransactionSnapshot());
-
/* Process and store remote tuple in the slot */
oldctx = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
slot_store_cstrings(remoteslot, rel, newtup.values);
/* Cleanup. */
ExecCloseIndices(estate->es_result_relation_info);
- PopActiveSnapshot();
- /* Handle queued AFTER triggers. */
- AfterTriggerEndQuery(estate);
-
- ExecResetTupleTable(estate->es_tupleTable, false);
- FreeExecutorState(estate);
+ finish_estate(estate);
logicalrep_rel_close(rel, NoLock);
/* Also populate extraUpdatedCols, in case we have generated columns */
fill_extraUpdatedCols(target_rte, rel->localrel);
- PushActiveSnapshot(GetTransactionSnapshot());
ExecOpenIndices(estate->es_result_relation_info, false);
/* Build the search tuple. */
}
/* Cleanup. */
+ EvalPlanQualEnd(&epqstate);
ExecCloseIndices(estate->es_result_relation_info);
- PopActiveSnapshot();
- /* Handle queued AFTER triggers. */
- AfterTriggerEndQuery(estate);
-
- EvalPlanQualEnd(&epqstate);
- ExecResetTupleTable(estate->es_tupleTable, false);
- FreeExecutorState(estate);
+ finish_estate(estate);
logicalrep_rel_close(rel, NoLock);
&estate->es_tupleTable);
EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1);
- PushActiveSnapshot(GetTransactionSnapshot());
ExecOpenIndices(estate->es_result_relation_info, false);
/* Find the tuple using the replica identity index. */
}
/* Cleanup. */
+ EvalPlanQualEnd(&epqstate);
ExecCloseIndices(estate->es_result_relation_info);
- PopActiveSnapshot();
- /* Handle queued AFTER triggers. */
- AfterTriggerEndQuery(estate);
-
- EvalPlanQualEnd(&epqstate);
- ExecResetTupleTable(estate->es_tupleTable, false);
- FreeExecutorState(estate);
+ finish_estate(estate);
logicalrep_rel_close(rel, NoLock);
List *relids = NIL;
List *relids_logged = NIL;
ListCell *lc;
- LOCKMODE lockmode = AccessExclusiveLock;
+ LOCKMODE lockmode = AccessExclusiveLock;
ensure_transaction();
else
PushActiveSnapshot(GetTransactionSnapshot());
+ /*
+ * We could remember the snapshot in portal->portalSnapshot,
+ * but presently there seems no need to, as this code path
+ * cannot be used for non-atomic execution. Hence there can't
+ * be any commit/abort that might destroy the snapshot.
+ */
+
/*
* Create QueryDesc in portal's context; for the moment, set
* the destination to DestNone.
bool isTopLevel, bool setHoldSnapshot,
DestReceiver *dest, char *completionTag)
{
- Node *utilityStmt = pstmt->utilityStmt;
- Snapshot snapshot;
-
/*
- * Set snapshot if utility stmt needs one. Most reliable way to do this
- * seems to be to enumerate those that do not need one; this is a short
- * list. Transaction control, LOCK, and SET must *not* set a snapshot
- * since they need to be executable at the start of a transaction-snapshot
- * mode transaction without freezing a snapshot. By extension we allow
- * SHOW not to set a snapshot. The other stmts listed are just efficiency
- * hacks. Beware of listing anything that can modify the database --- if,
- * say, it has to update an index with expressions that invoke
- * user-defined functions, then it had better have a snapshot.
+ * Set snapshot if utility stmt needs one.
*/
- if (!(IsA(utilityStmt, TransactionStmt) ||
- IsA(utilityStmt, LockStmt) ||
- IsA(utilityStmt, VariableSetStmt) ||
- IsA(utilityStmt, VariableShowStmt) ||
- IsA(utilityStmt, ConstraintsSetStmt) ||
- /* efficiency hacks from here down */
- IsA(utilityStmt, FetchStmt) ||
- IsA(utilityStmt, ListenStmt) ||
- IsA(utilityStmt, NotifyStmt) ||
- IsA(utilityStmt, UnlistenStmt) ||
- IsA(utilityStmt, CheckPointStmt)))
+ if (PlannedStmtRequiresSnapshot(pstmt))
{
- snapshot = GetTransactionSnapshot();
+ Snapshot snapshot = GetTransactionSnapshot();
+
/* If told to, register the snapshot we're using and save in portal */
if (setHoldSnapshot)
{
snapshot = RegisterSnapshot(snapshot);
portal->holdSnapshot = snapshot;
}
+ /* In any case, make the snapshot active and remember it in portal */
PushActiveSnapshot(snapshot);
/* PushActiveSnapshot might have copied the snapshot */
- snapshot = GetActiveSnapshot();
+ portal->portalSnapshot = GetActiveSnapshot();
}
else
- snapshot = NULL;
+ portal->portalSnapshot = NULL;
ProcessUtility(pstmt,
portal->sourceText,
MemoryContextSwitchTo(portal->portalContext);
/*
- * Some utility commands may pop the ActiveSnapshot stack from under us,
- * so be careful to only pop the stack if our snapshot is still at the
- * top.
+ * Some utility commands (e.g., VACUUM) pop the ActiveSnapshot stack from
+ * under us, so don't complain if it's now empty. Otherwise, our snapshot
+ * should be the top one; pop it. Note that this could be a different
+ * snapshot from the one we made above; see EnsurePortalSnapshotExists.
*/
- if (snapshot != NULL && ActiveSnapshotSet() &&
- snapshot == GetActiveSnapshot())
+ if (portal->portalSnapshot != NULL && ActiveSnapshotSet())
+ {
+ Assert(portal->portalSnapshot == GetActiveSnapshot());
PopActiveSnapshot();
+ }
+ portal->portalSnapshot = NULL;
}
/*
* from what holdSnapshot has.)
*/
PushCopiedSnapshot(snapshot);
+
+ /*
+ * As for PORTAL_ONE_SELECT portals, it does not seem
+ * necessary to maintain portal->portalSnapshot here.
+ */
+
active_snapshot_set = true;
}
else
portal->atEnd = false;
portal->portalPos = 0;
}
+
+/*
+ * PlannedStmtRequiresSnapshot - what it says on the tin
+ */
+bool
+PlannedStmtRequiresSnapshot(PlannedStmt *pstmt)
+{
+ Node *utilityStmt = pstmt->utilityStmt;
+
+ /* If it's not a utility statement, it definitely needs a snapshot */
+ if (utilityStmt == NULL)
+ return true;
+
+ /*
+ * Most utility statements need a snapshot, and the default presumption
+ * about new ones should be that they do too. Hence, enumerate those that
+ * do not need one.
+ *
+ * Transaction control, LOCK, and SET must *not* set a snapshot, since
+ * they need to be executable at the start of a transaction-snapshot-mode
+ * transaction without freezing a snapshot. By extension we allow SHOW
+ * not to set a snapshot. The other stmts listed are just efficiency
+ * hacks. Beware of listing anything that can modify the database --- if,
+ * say, it has to update an index with expressions that invoke
+ * user-defined functions, then it had better have a snapshot.
+ */
+ if (IsA(utilityStmt, TransactionStmt) ||
+ IsA(utilityStmt, LockStmt) ||
+ IsA(utilityStmt, VariableSetStmt) ||
+ IsA(utilityStmt, VariableShowStmt) ||
+ IsA(utilityStmt, ConstraintsSetStmt) ||
+ /* efficiency hacks from here down */
+ IsA(utilityStmt, FetchStmt) ||
+ IsA(utilityStmt, ListenStmt) ||
+ IsA(utilityStmt, NotifyStmt) ||
+ IsA(utilityStmt, UnlistenStmt) ||
+ IsA(utilityStmt, CheckPointStmt))
+ return false;
+
+ return true;
+}
+
+/*
+ * EnsurePortalSnapshotExists - recreate Portal-level snapshot, if needed
+ *
+ * Generally, we will have an active snapshot whenever we are executing
+ * inside a Portal, unless the Portal's query is one of the utility
+ * statements exempted from that rule (see PlannedStmtRequiresSnapshot).
+ * However, procedures and DO blocks can commit or abort the transaction,
+ * and thereby destroy all snapshots. This function can be called to
+ * re-establish the Portal-level snapshot when none exists.
+ */
+void
+EnsurePortalSnapshotExists(void)
+{
+ Portal portal;
+
+ /*
+ * Nothing to do if a snapshot is set. (We take it on faith that the
+ * outermost active snapshot belongs to some Portal; or if there is no
+ * Portal, it's somebody else's responsibility to manage things.)
+ */
+ if (ActiveSnapshotSet())
+ return;
+
+ /* Otherwise, we'd better have an active Portal */
+ portal = ActivePortal;
+ Assert(portal != NULL);
+ Assert(portal->portalSnapshot == NULL);
+
+ /* Create a new snapshot and make it active */
+ PushActiveSnapshot(GetTransactionSnapshot());
+ /* PushActiveSnapshot might have copied the snapshot */
+ portal->portalSnapshot = GetActiveSnapshot();
+}
portal->cleanup = NULL;
}
+ /* There shouldn't be an active snapshot anymore, except after error */
+ Assert(portal->portalSnapshot == NULL || !isTopCommit);
+
/*
* Remove portal from hash table. Because we do this here, we will not
* come back to try to remove the portal again if there's any error in the
portal->holdSnapshot = NULL;
}
portal->resowner = NULL;
+ /* Clear portalSnapshot too, for cleanliness */
+ portal->portalSnapshot = NULL;
continue;
}
}
}
}
+
+/*
+ * Drop the outer active snapshots for all portals, so that no snapshots
+ * remain active.
+ *
+ * Like HoldPinnedPortals, this must be called when initiating a COMMIT or
+ * ROLLBACK inside a procedure. This has to be separate from that since it
+ * should not be run until we're done with steps that are likely to fail.
+ *
+ * It's tempting to fold this into PreCommit_Portals, but to do so, we'd
+ * need to clean up snapshot management in VACUUM and perhaps other places.
+ */
+void
+ForgetPortalSnapshots(void)
+{
+ HASH_SEQ_STATUS status;
+ PortalHashEnt *hentry;
+ int numPortalSnaps = 0;
+ int numActiveSnaps = 0;
+
+ /* First, scan PortalHashTable and clear portalSnapshot fields */
+ hash_seq_init(&status, PortalHashTable);
+
+ while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
+ {
+ Portal portal = hentry->portal;
+
+ if (portal->portalSnapshot != NULL)
+ {
+ portal->portalSnapshot = NULL;
+ numPortalSnaps++;
+ }
+ /* portal->holdSnapshot will be cleaned up in PreCommit_Portals */
+ }
+
+ /*
+ * Now, pop all the active snapshots, which should be just those that were
+ * portal snapshots. Ideally we'd drive this directly off the portal
+ * scan, but there's no good way to visit the portals in the correct
+ * order. So just cross-check after the fact.
+ */
+ while (ActiveSnapshotSet())
+ {
+ PopActiveSnapshot();
+ numActiveSnaps++;
+ }
+
+ if (numPortalSnaps != numActiveSnaps)
+ elog(ERROR, "portal snapshots (%d) did not account for all active snapshots (%d)",
+ numPortalSnaps, numActiveSnaps);
+}
int magic; /* should equal _SPI_PLAN_MAGIC */
bool saved; /* saved or unsaved plan? */
bool oneshot; /* one-shot plan? */
- bool no_snapshots; /* let the caller handle the snapshots */
+ bool no_snapshots; /* allow nonatomic CALL/DO execution */
List *plancache_list; /* one CachedPlanSource per parsetree */
MemoryContext plancxt; /* Context containing _SPI_plan and data */
int cursor_options; /* Cursor options used for planning */
#include "nodes/parsenodes.h"
#include "utils/portal.h"
+struct PlannedStmt; /* avoid including plannodes.h here */
+
extern PGDLLIMPORT Portal ActivePortal;
long count,
DestReceiver *dest);
+extern bool PlannedStmtRequiresSnapshot(struct PlannedStmt *pstmt);
+
+extern void EnsurePortalSnapshotExists(void);
+
#endif /* PQUERY_H */
/* Presentation data, primarily used by the pg_cursors system view */
TimestampTz creation_time; /* time at which this portal was defined */
bool visible; /* include this portal in pg_cursors? */
+
+ /*
+ * Outermost ActiveSnapshot for execution of the portal's queries. For
+ * all but a few utility commands, we require such a snapshot to exist.
+ * This ensures that TOAST references in query results can be detoasted,
+ * and helps to reduce thrashing of the process's exposed xmin.
+ */
+ Snapshot portalSnapshot; /* active snapshot, or NULL if none */
} PortalData;
/*
extern void PortalHashTableDeleteAll(void);
extern bool ThereAreNoReadyPortals(void);
extern void HoldPinnedPortals(void);
+extern void ForgetPortalSnapshots(void);
#endif /* PORTAL_H */
PLpgSQL_variable *volatile cur_target = stmt->target;
volatile LocalTransactionId before_lxid;
LocalTransactionId after_lxid;
- volatile bool pushed_active_snap = false;
volatile int rc;
/*
Assert(!expr->expr_simple_expr);
/*
- * The procedure call could end transactions, which would upset
- * the snapshot management in SPI_execute*, so don't let it do it.
- * Instead, we set the snapshots ourselves below.
+ * Tell SPI to allow non-atomic execution. (The field name is a
+ * legacy choice.)
*/
plan->no_snapshots = true;
before_lxid = MyProc->lxid;
- /*
- * Set snapshot only for non-read-only procedures, similar to SPI
- * behavior.
- */
- if (!estate->readonly_func)
- {
- PushActiveSnapshot(GetTransactionSnapshot());
- pushed_active_snap = true;
- }
-
rc = SPI_execute_plan_with_paramlist(expr->plan, paramLI,
estate->readonly_func, 0);
}
after_lxid = MyProc->lxid;
- if (before_lxid == after_lxid)
- {
- /*
- * If we are still in the same transaction after the call, pop the
- * snapshot that we might have pushed. (If it's a new transaction,
- * then all the snapshots are gone already.)
- */
- if (pushed_active_snap)
- PopActiveSnapshot();
- }
- else
+ if (before_lxid != after_lxid)
{
/*
* If we are in a new transaction after the call, we need to build new
*
* We just parse and execute the statement normally, but we have to do it
* without setting a snapshot, for things like SET TRANSACTION.
+ * XXX spi.c now handles this correctly, so we no longer need a special case.
*/
static int
exec_stmt_set(PLpgSQL_execstate *estate, PLpgSQL_stmt_set *stmt)
int rc;
if (expr->plan == NULL)
- {
exec_prepare_plan(estate, expr, 0, true);
- expr->plan->no_snapshots = true;
- }
rc = SPI_execute_plan(expr->plan, NULL, NULL, estate->readonly_func, 0);
s1: NOTICE: length(r) = 9002
s1: NOTICE: length(r) = 12002
step assign6: <... completed>
+
+starting permutation: fetch-after-commit
+pg_advisory_unlock_all
+
+
+pg_advisory_unlock_all
+
+
+s1: NOTICE: length(t) = 6000
+s1: NOTICE: length(t) = 9000
+s1: NOTICE: length(t) = 12000
+step fetch-after-commit:
+do $$
+ declare
+ r record;
+ t text;
+ begin
+ insert into test1 values (2, repeat('bar', 3000));
+ insert into test1 values (3, repeat('baz', 4000));
+ for r in select test1.a from test1 loop
+ commit;
+ select b into t from test1 where a = r.a;
+ raise notice 'length(t) = %', length(t);
+ end loop;
+ end;
+$$;
+
$$;
}
+# Check that the results of a query can be detoasted just after committing
+# (there's no interaction with VACUUM here)
+step "fetch-after-commit"
+{
+do $$
+ declare
+ r record;
+ t text;
+ begin
+ insert into test1 values (2, repeat('bar', 3000));
+ insert into test1 values (3, repeat('baz', 4000));
+ for r in select test1.a from test1 loop
+ commit;
+ select b into t from test1 where a = r.a;
+ raise notice 'length(t) = %', length(t);
+ end loop;
+ end;
+$$;
+}
+
session "s2"
setup
{
permutation "lock" "assign4" "vacuum" "unlock"
permutation "lock" "assign5" "vacuum" "unlock"
permutation "lock" "assign6" "vacuum" "unlock"
+permutation "fetch-after-commit"
projects / postgresql.git / commitdiff