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[PATCH 2/8] Expand the external data before forming the tuple 2+ messages / 2 participants [nested] [flat]
* [PATCH 2/8] Expand the external data before forming the tuple @ 2021-03-04 09:25 Dilip Kumar <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Dilip Kumar @ 2021-03-04 09:25 UTC (permalink / raw) All the callers of HeapTupleGetDatum and HeapTupleHeaderGetDatum, who might contain the external varlena in their tuple, try to flatten the external varlena before forming the tuple wherever it is possible. Dilip Kumar based on idea by Robert Haas --- src/backend/executor/execExprInterp.c | 29 +++++++++++++++++++++++++-- src/backend/utils/adt/jsonfuncs.c | 8 ++++++-- src/pl/plpgsql/src/pl_exec.c | 5 ++++- 3 files changed, 37 insertions(+), 5 deletions(-) diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c index 20949a5dec..c3754acca4 100644 --- a/src/backend/executor/execExprInterp.c +++ b/src/backend/executor/execExprInterp.c @@ -2840,12 +2840,25 @@ ExecEvalRow(ExprState *state, ExprEvalStep *op) { HeapTuple tuple; + /* Retrieve externally stored values and decompress. */ + for (int i = 0; i < op->d.row.tupdesc->natts; i++) + { + Form_pg_attribute attr = TupleDescAttr(op->d.row.tupdesc, i); + + if (op->d.row.elemnulls[i] || attr->attlen != -1 || + !VARATT_IS_EXTERNAL(DatumGetPointer(op->d.row.elemvalues[i]))) + continue; + + op->d.row.elemvalues[i] = + PointerGetDatum(PG_DETOAST_DATUM_PACKED(op->d.row.elemvalues[i])); + } + /* build tuple from evaluated field values */ tuple = heap_form_tuple(op->d.row.tupdesc, op->d.row.elemvalues, op->d.row.elemnulls); - *op->resvalue = HeapTupleGetDatum(tuple); + *op->resvalue = HeapTupleGetRawDatum(tuple); *op->resnull = false; } @@ -3085,12 +3098,24 @@ ExecEvalFieldStoreForm(ExprState *state, ExprEvalStep *op, ExprContext *econtext { HeapTuple tuple; + /* Retrieve externally stored values and decompress. */ + for (int i = 0; i < (*op->d.fieldstore.argdesc)->natts; i++) + { + Form_pg_attribute attr = TupleDescAttr(*op->d.fieldstore.argdesc, i); + + if (op->d.fieldstore.nulls[i] || attr->attlen != -1 || + !VARATT_IS_EXTERNAL(DatumGetPointer(op->d.fieldstore.values[i]))) + continue; + op->d.fieldstore.values[i] = PointerGetDatum( + PG_DETOAST_DATUM_PACKED(op->d.fieldstore.values[i])); + } + /* argdesc should already be valid from the DeForm step */ tuple = heap_form_tuple(*op->d.fieldstore.argdesc, op->d.fieldstore.values, op->d.fieldstore.nulls); - *op->resvalue = HeapTupleGetDatum(tuple); + *op->resvalue = HeapTupleGetRawDatum(tuple); *op->resnull = false; } diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c index 511467280f..c3d464f42b 100644 --- a/src/backend/utils/adt/jsonfuncs.c +++ b/src/backend/utils/adt/jsonfuncs.c @@ -2968,7 +2968,7 @@ populate_composite(CompositeIOData *io, /* populate resulting record tuple */ tuple = populate_record(io->tupdesc, &io->record_io, defaultval, mcxt, &jso); - result = HeapTupleHeaderGetDatum(tuple); + result = HeapTupleHeaderGetRawDatum(tuple); JsObjectFree(&jso); } @@ -3387,6 +3387,10 @@ populate_record(TupleDesc tupdesc, nulls[i] ? (Datum) 0 : values[i], &field, &nulls[i]); + + if (!nulls[i] && att->attlen == -1 && + VARATT_IS_EXTERNAL(DatumGetPointer(values[i]))) + values[i] = PointerGetDatum(PG_DETOAST_DATUM_PACKED(values[i])); } res = heap_form_tuple(tupdesc, values, nulls); @@ -3765,7 +3769,7 @@ populate_recordset_record(PopulateRecordsetState *state, JsObject *obj) /* if it's domain over composite, check domain constraints */ if (cache->c.typcat == TYPECAT_COMPOSITE_DOMAIN) - domain_check(HeapTupleHeaderGetDatum(tuphead), false, + domain_check(HeapTupleHeaderGetRawDatum(tuphead), false, cache->argtype, &cache->c.io.composite.domain_info, cache->fn_mcxt); diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c index b4c70aaa7f..fd073767bc 100644 --- a/src/pl/plpgsql/src/pl_exec.c +++ b/src/pl/plpgsql/src/pl_exec.c @@ -5326,7 +5326,7 @@ exec_eval_datum(PLpgSQL_execstate *estate, elog(ERROR, "row not compatible with its own tupdesc"); *typeid = row->rowtupdesc->tdtypeid; *typetypmod = row->rowtupdesc->tdtypmod; - *value = HeapTupleGetDatum(tup); + *value = HeapTupleGetRawDatum(tup); *isnull = false; MemoryContextSwitchTo(oldcontext); break; @@ -7300,6 +7300,9 @@ make_tuple_from_row(PLpgSQL_execstate *estate, &dvalues[i], &nulls[i]); if (fieldtypeid != TupleDescAttr(tupdesc, i)->atttypid) return NULL; + if (!nulls[i] && TupleDescAttr(tupdesc, i)->attlen == -1 && + VARATT_IS_EXTERNAL(DatumGetPointer(dvalues[i]))) + dvalues[i] = PointerGetDatum(PG_DETOAST_DATUM_PACKED(dvalues[i])); /* XXX should we insist on typmod match, too? */ } -- 2.17.0 --cvVnyQ+4j833TQvp Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="0003-Disallow-compressed-data-inside-container-types.patch" ^ permalink raw reply [nested|flat] 2+ messages in thread
* [PATCH 3/6] Move conversion of a "historic" to MVCC snapshot to a separate function. @ 2026-01-27 10:48 Antonin Houska <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Antonin Houska @ 2026-01-27 10:48 UTC (permalink / raw) The conversion is now handled by SnapBuildMVCCFromHistoric(). REPACK CONCURRENTLY will also need it. --- src/backend/replication/logical/snapbuild.c | 59 +++++++++++++++++---- src/backend/utils/time/snapmgr.c | 3 +- src/include/replication/snapbuild.h | 1 + src/include/utils/snapmgr.h | 1 + 4 files changed, 52 insertions(+), 12 deletions(-) diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c index 7f79621b57e..a738ad8a864 100644 --- a/src/backend/replication/logical/snapbuild.c +++ b/src/backend/replication/logical/snapbuild.c @@ -440,10 +440,7 @@ Snapshot SnapBuildInitialSnapshot(SnapBuild *builder) { Snapshot snap; - TransactionId xid; TransactionId safeXid; - TransactionId *newxip; - int newxcnt = 0; Assert(XactIsoLevel == XACT_REPEATABLE_READ); Assert(builder->building_full_snapshot); @@ -485,7 +482,35 @@ SnapBuildInitialSnapshot(SnapBuild *builder) MyProc->xmin = snap->xmin; - /* allocate in transaction context */ + /* Convert the historic snapshot to MVCC snapshot. */ + return SnapBuildMVCCFromHistoric(snap, true); +} + +/* + * Turn a historic MVCC snapshot into an ordinary MVCC snapshot. + * + * Unlike a regular (non-historic) MVCC snapshot, the 'xip' array of this + * snapshot contains not only running main transactions, but also their + * subtransactions. On the other hand, 'subxip' will usually be empty. This + * difference does not affect the result of XidInMVCCSnapshot() because it + * searches both in 'xip' and 'subxip'. + * + * Pass true for 'in_place' if you don't care about modifying the source + * snapshot. If you need a new instance, and one that was allocated as a + * single chunk of memory, pass false. + */ +Snapshot +SnapBuildMVCCFromHistoric(Snapshot snapshot, bool in_place) +{ + TransactionId xid; + TransactionId *oldxip = snapshot->xip; + uint32 oldxcnt = snapshot->xcnt; + TransactionId *newxip; + int newxcnt = 0; + Snapshot result; + + Assert(snapshot->snapshot_type == SNAPSHOT_HISTORIC_MVCC); + newxip = palloc_array(TransactionId, GetMaxSnapshotXidCount()); /* @@ -494,7 +519,7 @@ SnapBuildInitialSnapshot(SnapBuild *builder) * classical snapshot by marking all non-committed transactions as * in-progress. This can be expensive. */ - for (xid = snap->xmin; NormalTransactionIdPrecedes(xid, snap->xmax);) + for (xid = snapshot->xmin; NormalTransactionIdPrecedes(xid, snapshot->xmax);) { void *test; @@ -502,7 +527,7 @@ SnapBuildInitialSnapshot(SnapBuild *builder) * Check whether transaction committed using the decoding snapshot * meaning of ->xip. */ - test = bsearch(&xid, snap->xip, snap->xcnt, + test = bsearch(&xid, snapshot->xip, snapshot->xcnt, sizeof(TransactionId), xidComparator); if (test == NULL) @@ -519,11 +544,25 @@ SnapBuildInitialSnapshot(SnapBuild *builder) } /* adjust remaining snapshot fields as needed */ - snap->snapshot_type = SNAPSHOT_MVCC; - snap->xcnt = newxcnt; - snap->xip = newxip; + snapshot->xcnt = newxcnt; + snapshot->xip = newxip; + + if (in_place) + result = snapshot; + else + { + result = CopySnapshot(snapshot); + + /* Restore the original values so the source is intact. */ + snapshot->xip = oldxip; + snapshot->xcnt = oldxcnt; + + /* newxip has been copied */ + pfree(newxip); + } + result->snapshot_type = SNAPSHOT_MVCC; - return snap; + return result; } /* diff --git a/src/backend/utils/time/snapmgr.c b/src/backend/utils/time/snapmgr.c index 2e6197f5f35..3af1b366adf 100644 --- a/src/backend/utils/time/snapmgr.c +++ b/src/backend/utils/time/snapmgr.c @@ -213,7 +213,6 @@ typedef struct ExportedSnapshot static List *exportedSnapshots = NIL; /* Prototypes for local functions */ -static Snapshot CopySnapshot(Snapshot snapshot); static void UnregisterSnapshotNoOwner(Snapshot snapshot); static void FreeSnapshot(Snapshot snapshot); static void SnapshotResetXmin(void); @@ -604,7 +603,7 @@ SetTransactionSnapshot(Snapshot sourcesnap, VirtualTransactionId *sourcevxid, * The copy is palloc'd in TopTransactionContext and has initial refcounts set * to 0. The returned snapshot has the copied flag set. */ -static Snapshot +Snapshot CopySnapshot(Snapshot snapshot) { Snapshot newsnap; diff --git a/src/include/replication/snapbuild.h b/src/include/replication/snapbuild.h index ccded021433..34383dea776 100644 --- a/src/include/replication/snapbuild.h +++ b/src/include/replication/snapbuild.h @@ -73,6 +73,7 @@ extern void FreeSnapshotBuilder(SnapBuild *builder); extern void SnapBuildSnapDecRefcount(Snapshot snap); extern Snapshot SnapBuildInitialSnapshot(SnapBuild *builder); +extern Snapshot SnapBuildMVCCFromHistoric(Snapshot snapshot, bool in_place); extern const char *SnapBuildExportSnapshot(SnapBuild *builder); extern void SnapBuildClearExportedSnapshot(void); extern void SnapBuildResetExportedSnapshotState(void); diff --git a/src/include/utils/snapmgr.h b/src/include/utils/snapmgr.h index b8c01a291a1..de824945f0b 100644 --- a/src/include/utils/snapmgr.h +++ b/src/include/utils/snapmgr.h @@ -63,6 +63,7 @@ extern Snapshot GetTransactionSnapshot(void); extern Snapshot GetLatestSnapshot(void); extern void SnapshotSetCommandId(CommandId curcid); +extern Snapshot CopySnapshot(Snapshot snapshot); extern Snapshot GetCatalogSnapshot(Oid relid); extern Snapshot GetNonHistoricCatalogSnapshot(Oid relid); extern void InvalidateCatalogSnapshot(void); -- 2.47.3 --=-=-= Content-Type: text/plain Content-Disposition: attachment; filename=v32-0004-Add-CONCURRENTLY-option-to-REPACK-command.patch ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2026-01-27 10:48 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2021-03-04 09:25 [PATCH 2/8] Expand the external data before forming the tuple Dilip Kumar <[email protected]> 2026-01-27 10:48 [PATCH 3/6] Move conversion of a "historic" to MVCC snapshot to a separate function. Antonin Houska <[email protected]>
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