/* * Helper function for the various SQL callable logical decoding functions. */ static Datum pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool binary) { Name name; XLogRecPtr upto_lsn; int32 upto_nchanges; ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; MemoryContext per_query_ctx; MemoryContext oldcontext; XLogRecPtr end_of_wal; XLogRecPtr startptr; LogicalDecodingContext *ctx; ResourceOwner old_resowner = CurrentResourceOwner; ArrayType *arr; Size ndim; List *options = NIL; DecodingOutputState *p; check_permissions(); CheckLogicalDecodingRequirements(); if (PG_ARGISNULL(0)) ereport(ERROR, (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED), errmsg("slot name must not be null"))); name = PG_GETARG_NAME(0); if (PG_ARGISNULL(1)) upto_lsn = InvalidXLogRecPtr; else upto_lsn = PG_GETARG_LSN(1); if (PG_ARGISNULL(2)) upto_nchanges = InvalidXLogRecPtr; else upto_nchanges = PG_GETARG_INT32(2); if (PG_ARGISNULL(3)) ereport(ERROR, (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED), errmsg("options array must not be null"))); arr = PG_GETARG_ARRAYTYPE_P(3); /* check to see if caller supports us returning a tuplestore */ if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("set-valued function called in context that cannot accept a set"))); if (!(rsinfo->allowedModes & SFRM_Materialize)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("materialize mode required, but it is not allowed in this context"))); /* state to write output to */ p = palloc0(sizeof(DecodingOutputState)); p->binary_output = binary; /* Build a tuple descriptor for our result type */ if (get_call_result_type(fcinfo, NULL, &p->tupdesc) != TYPEFUNC_COMPOSITE) elog(ERROR, "return type must be a row type"); per_query_ctx = rsinfo->econtext->ecxt_per_query_memory; oldcontext = MemoryContextSwitchTo(per_query_ctx); /* Deconstruct options array */ ndim = ARR_NDIM(arr); if (ndim > 1) { ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("array must be one-dimensional"))); } else if (array_contains_nulls(arr)) { ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("array must not contain nulls"))); } else if (ndim == 1) { int nelems; Datum *datum_opts; int i; Assert(ARR_ELEMTYPE(arr) == TEXTOID); deconstruct_array(arr, TEXTOID, -1, false, 'i', &datum_opts, NULL, &nelems); if (nelems % 2 != 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("array must have even number of elements"))); for (i = 0; i < nelems; i += 2) { char *name = TextDatumGetCString(datum_opts[i]); char *opt = TextDatumGetCString(datum_opts[i + 1]); options = lappend(options, makeDefElem(name, (Node *) makeString(opt), -1)); } } p->tupstore = tuplestore_begin_heap(true, false, work_mem); rsinfo->returnMode = SFRM_Materialize; rsinfo->setResult = p->tupstore; rsinfo->setDesc = p->tupdesc; /* * Compute the current end-of-wal and maintain ThisTimeLineID. * RecoveryInProgress() will update ThisTimeLineID on promotion. */ if (!RecoveryInProgress()) end_of_wal = GetFlushRecPtr(); else end_of_wal = GetXLogReplayRecPtr(&ThisTimeLineID); ReplicationSlotAcquire(NameStr(*name), true); PG_TRY(); { /* restart at slot's confirmed_flush */ ctx = CreateDecodingContext(InvalidXLogRecPtr, options, false, logical_read_local_xlog_page, LogicalOutputPrepareWrite, LogicalOutputWrite, NULL); MemoryContextSwitchTo(oldcontext); /* * Check whether the output plugin writes textual output if that's * what we need. */ if (!binary && ctx->options.output_type !=OUTPUT_PLUGIN_TEXTUAL_OUTPUT) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("logical decoding output plugin \"%s\" produces binary output, but function \"%s\" expects textual data", NameStr(MyReplicationSlot->data.plugin), format_procedure(fcinfo->flinfo->fn_oid)))); ctx->output_writer_private = p; /* * Decoding of WAL must start at restart_lsn so that the entirety of * xacts that committed after the slot's confirmed_flush can be * accumulated into reorder buffers. */ startptr = MyReplicationSlot->data.restart_lsn; CurrentResourceOwner = ResourceOwnerCreate(CurrentResourceOwner, "logical decoding"); /* invalidate non-timetravel entries */ InvalidateSystemCaches(); /* Decode until we run out of records */ while ((startptr != InvalidXLogRecPtr && startptr < end_of_wal) || (ctx->reader->EndRecPtr != InvalidXLogRecPtr && ctx->reader->EndRecPtr < end_of_wal)) { XLogRecord *record; char *errm = NULL; record = XLogReadRecord(ctx->reader, startptr, &errm); if (errm) elog(ERROR, "%s", errm); /* * Now that we've set up the xlog reader state, subsequent calls * pass InvalidXLogRecPtr to say "continue from last record" */ startptr = InvalidXLogRecPtr; /* * The {begin_txn,change,commit_txn}_wrapper callbacks above will * store the description into our tuplestore. */ if (record != NULL) LogicalDecodingProcessRecord(ctx, ctx->reader); /* check limits */ if (upto_lsn != InvalidXLogRecPtr && upto_lsn <= ctx->reader->EndRecPtr) break; if (upto_nchanges != 0 && upto_nchanges <= p->returned_rows) break; CHECK_FOR_INTERRUPTS(); } tuplestore_donestoring(tupstore); CurrentResourceOwner = old_resowner; /* * Next time, start where we left off. (Hunting things, the family * business..) */ if (ctx->reader->EndRecPtr != InvalidXLogRecPtr && confirm) { LogicalConfirmReceivedLocation(ctx->reader->EndRecPtr); /* * If only the confirmed_flush_lsn has changed the slot won't get * marked as dirty by the above. Callers on the walsender * interface are expected to keep track of their own progress and * don't need it written out. But SQL-interface users cannot * specify their own start positions and it's harder for them to * keep track of their progress, so we should make more of an * effort to save it for them. * * Dirty the slot so it's written out at the next checkpoint. * We'll still lose its position on crash, as documented, but it's * better than always losing the position even on clean restart. */ ReplicationSlotMarkDirty(); } /* free context, call shutdown callback */ FreeDecodingContext(ctx); ReplicationSlotRelease(); InvalidateSystemCaches(); } PG_CATCH(); { /* clear all timetravel entries */ InvalidateSystemCaches(); PG_RE_THROW(); } PG_END_TRY(); return (Datum) 0; }
/* * Helper function for the various SQL callable logical decoding functions. */ static Datum pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool binary) { Name name = PG_GETARG_NAME(0); XLogRecPtr upto_lsn; int32 upto_nchanges; ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; MemoryContext per_query_ctx; MemoryContext oldcontext; XLogRecPtr end_of_wal; XLogRecPtr startptr; LogicalDecodingContext *ctx; ResourceOwner old_resowner = CurrentResourceOwner; ArrayType *arr; Size ndim; List *options = NIL; DecodingOutputState *p; if (PG_ARGISNULL(1)) upto_lsn = InvalidXLogRecPtr; else upto_lsn = PG_GETARG_LSN(1); if (PG_ARGISNULL(2)) upto_nchanges = InvalidXLogRecPtr; else upto_nchanges = PG_GETARG_INT32(2); /* check to see if caller supports us returning a tuplestore */ if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("set-valued function called in context that cannot accept a set"))); if (!(rsinfo->allowedModes & SFRM_Materialize)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("materialize mode required, but it is not allowed in this context"))); /* state to write output to */ p = palloc0(sizeof(DecodingOutputState)); p->binary_output = binary; /* Build a tuple descriptor for our result type */ if (get_call_result_type(fcinfo, NULL, &p->tupdesc) != TYPEFUNC_COMPOSITE) elog(ERROR, "return type must be a row type"); check_permissions(); CheckLogicalDecodingRequirements(); arr = PG_GETARG_ARRAYTYPE_P(3); ndim = ARR_NDIM(arr); per_query_ctx = rsinfo->econtext->ecxt_per_query_memory; oldcontext = MemoryContextSwitchTo(per_query_ctx); if (ndim > 1) { ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("array must be one-dimensional"))); } else if (array_contains_nulls(arr)) { ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("array must not contain nulls"))); } else if (ndim == 1) { int nelems; Datum *datum_opts; int i; Assert(ARR_ELEMTYPE(arr) == TEXTOID); deconstruct_array(arr, TEXTOID, -1, false, 'i', &datum_opts, NULL, &nelems); if (nelems % 2 != 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("array must have even number of elements"))); for (i = 0; i < nelems; i += 2) { char *name = TextDatumGetCString(datum_opts[i]); char *opt = TextDatumGetCString(datum_opts[i + 1]); options = lappend(options, makeDefElem(name, (Node *) makeString(opt))); } } p->tupstore = tuplestore_begin_heap(true, false, work_mem); rsinfo->returnMode = SFRM_Materialize; rsinfo->setResult = p->tupstore; rsinfo->setDesc = p->tupdesc; /* compute the current end-of-wal */ if (!RecoveryInProgress()) end_of_wal = GetFlushRecPtr(); else end_of_wal = GetXLogReplayRecPtr(NULL); CheckLogicalDecodingRequirements(); ReplicationSlotAcquire(NameStr(*name)); PG_TRY(); { ctx = CreateDecodingContext(InvalidXLogRecPtr, options, logical_read_local_xlog_page, LogicalOutputPrepareWrite, LogicalOutputWrite); MemoryContextSwitchTo(oldcontext); /* * Check whether the output pluggin writes textual output if that's * what we need. */ if (!binary && ctx->options.output_type != OUTPUT_PLUGIN_TEXTUAL_OUTPUT) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("output plugin cannot produce binary output"))); ctx->output_writer_private = p; startptr = MyReplicationSlot->data.restart_lsn; CurrentResourceOwner = ResourceOwnerCreate(CurrentResourceOwner, "logical decoding"); /* invalidate non-timetravel entries */ InvalidateSystemCaches(); while ((startptr != InvalidXLogRecPtr && startptr < end_of_wal) || (ctx->reader->EndRecPtr && ctx->reader->EndRecPtr < end_of_wal)) { XLogRecord *record; char *errm = NULL; record = XLogReadRecord(ctx->reader, startptr, &errm); if (errm) elog(ERROR, "%s", errm); startptr = InvalidXLogRecPtr; /* * The {begin_txn,change,commit_txn}_wrapper callbacks above will * store the description into our tuplestore. */ if (record != NULL) LogicalDecodingProcessRecord(ctx, record); /* check limits */ if (upto_lsn != InvalidXLogRecPtr && upto_lsn <= ctx->reader->EndRecPtr) break; if (upto_nchanges != 0 && upto_nchanges <= p->returned_rows) break; } } PG_CATCH(); { /* clear all timetravel entries */ InvalidateSystemCaches(); PG_RE_THROW(); } PG_END_TRY(); tuplestore_donestoring(tupstore); CurrentResourceOwner = old_resowner; /* * Next time, start where we left off. (Hunting things, the family * business..) */ if (ctx->reader->EndRecPtr != InvalidXLogRecPtr && confirm) LogicalConfirmReceivedLocation(ctx->reader->EndRecPtr); /* free context, call shutdown callback */ FreeDecodingContext(ctx); ReplicationSlotRelease(); InvalidateSystemCaches(); return (Datum) 0; }