Get things working enough that code is executing & giving nonsense like avg() wanting to create arrays with 16777216 dimensions

src/backend/distributed/citus--8.4-1--8.4-2.sql

@@ -1,61 +0,0 @@
-CREATE FUNCTION stype_serialize(internal, oid, ...)
-RETURNS internal
-AS 'MODULE_PATHNAME'
-LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
-
-CREATE FUNCTION stype_deserialize(internal, oid, ...)
-RETURNS internal
-AS 'MODULE_PATHNAME'
-LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
-
-CREATE FUNCTION stype_combine(internal, oid, ...)
-RETURNS internal
-AS 'MODULE_PATHNAME'
-LANGUAGE C PARALLEL SAFE;
-
-CREATE FUNCTION worker_partial_agg_sfunc(internal, oid, ...)
-RETURNS internal
-AS 'MODULE_PATHNAME'
-LANGUAGE C PARALLEL SAFE;
-
-CREATE FUNCTION worker_partial_agg_ffunc(internal, oid, ...)
-RETURNS internal
-AS 'MODULE_PATHNAME'
-LANGUAGE C PARALLEL SAFE;
-
-CREATE FUNCTION coord_combine_agg_sfunc(internal, oid, ...)
-RETURNS internal
-AS 'MODULE_PATHNAME'
-LANGUAGE C PARALLEL SAFE;
-
-CREATE FUNCTION coord_combine_agg_ffunc(internal, oid, ...)
-RETURNS internal
-AS 'MODULE_PATHNAME'
-LANGUAGE C PARALLEL SAFE;
-
--- select worker_partial_agg(agg, ...)
--- equivalent to
--- select serialize_stype(agg_without_ffunc(...))
-CREATE AGGREGATE worker_partial_agg(oid, ...) (
-	STYPE = internal,
-	SFUNC = worker_partial_agg_sfunc,
-	FINALFUNC = worker_partial_agg_ffunc,
-	COMBINEFUNC = stypebox_combine,
-	SERIALFUNC = stypebox_serialize,
-	DESERIALFUNC = stypebox_deserialize,
-	PARALLEL = SAFE
-)
-
--- select coord_combine_agg(agg, col)
--- equivalent to
--- select agg_ffunc(agg_combine(col))
-CREATE AGGREGATE coord_combine_agg(oid, ...) (
-	STYPE = internal,
-	SFUNC = coord_combine_sfunc,
-	FINALFUNC = coord_combine_agg_ffunc,
-	FINALFUNC_EXTRA,
-	COMBINEFUNC = stypebox_combine,
-	SERIALFUNC = stypebox_serialize,
-	DESERIALFUNC = stypebox_deserialize,
-	PARALLEL = SAFE
-)

src/backend/distributed/citus--8.4-1--8.4-customagg.sql

@@ -0,0 +1,65 @@
+SET search_path = 'pg_catalog';
+
+CREATE FUNCTION citus_stype_serialize(internal)
+RETURNS bytea
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
+
+CREATE FUNCTION citus_stype_deserialize(bytea, internal)
+RETURNS internal
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
+
+CREATE FUNCTION citus_stype_combine(internal, internal)
+RETURNS internal
+AS 'MODULE_PATHNAME'
+LANGUAGE C PARALLEL SAFE;
+
+CREATE FUNCTION worker_partial_agg_sfunc(internal, oid, anyelement)
+RETURNS internal
+AS 'MODULE_PATHNAME'
+LANGUAGE C PARALLEL SAFE;
+
+CREATE FUNCTION worker_partial_agg_ffunc(internal)
+RETURNS bytea
+AS 'MODULE_PATHNAME'
+LANGUAGE C PARALLEL SAFE;
+
+CREATE FUNCTION coord_combine_agg_sfunc(internal, oid, bytea, anyelement)
+RETURNS internal
+AS 'MODULE_PATHNAME'
+LANGUAGE C PARALLEL SAFE;
+
+CREATE FUNCTION coord_combine_agg_ffunc(internal, oid, bytea, anyelement)
+RETURNS anyelement
+AS 'MODULE_PATHNAME'
+LANGUAGE C PARALLEL SAFE;
+
+-- select worker_partial_agg(agg, ...)
+-- equivalent to
+-- select serialize_stype(agg_without_ffunc(...))
+CREATE AGGREGATE worker_partial_agg(oid, anyelement) (
+	STYPE = internal,
+	SFUNC = worker_partial_agg_sfunc,
+	FINALFUNC = worker_partial_agg_ffunc,
+	COMBINEFUNC = citus_stype_combine,
+	SERIALFUNC = citus_stype_serialize,
+	DESERIALFUNC = citus_stype_deserialize,
+	PARALLEL = SAFE
+);
+
+-- select coord_combine_agg(agg, col)
+-- equivalent to
+-- select agg_ffunc(agg_combine(col))
+CREATE AGGREGATE coord_combine_agg(oid, bytea, anyelement) (
+	STYPE = internal,
+	SFUNC = coord_combine_agg_sfunc,
+	FINALFUNC = coord_combine_agg_ffunc,
+	FINALFUNC_EXTRA,
+	COMBINEFUNC = citus_stype_combine,
+	SERIALFUNC = citus_stype_serialize,
+	DESERIALFUNC = citus_stype_deserialize,
+	PARALLEL = SAFE
+);
+
+RESET search_path;

src/backend/distributed/planner/multi_logical_optimizer.c

@@ -1512,8 +1512,6 @@ MasterAggregateExpression(Aggref *originalAggregate,
 	HeapTuple aggTuple;
 	Form_pg_aggregate aggform;
 	Oid combine;
-	Oid serial = InvalidOid;
-	Oid deserial = InvalidOid;
 
 	aggTuple = SearchSysCache1(AGGFNOID,
 							   ObjectIdGetDatum(originalAggregate->aggfnoid));
@@ -1527,11 +1525,6 @@ MasterAggregateExpression(Aggref *originalAggregate,
 	{
 		aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);
 		combine = aggform->aggcombinefn;
-		if (combine != InvalidOid && originalAggregate->aggtranstype == INTERNALOID)
-		{
-			serial = aggform->aggserialfn;
-			deserial = aggform->aggdeserialfn;
-		}
 		ReleaseSysCache(aggTuple);
 	}
 
@@ -1548,6 +1541,8 @@ MasterAggregateExpression(Aggref *originalAggregate,
 		int32 workerReturnTypeMod = -1;
 		Oid workerCollationId = InvalidOid;
 
+		elog(WARNING, "coord_combine_agg %d %d", coordCombineId,
+			 originalAggregate->aggfnoid);
 
 		aggparam = makeConst(OIDOID, -1, InvalidOid, sizeof(Oid), ObjectIdGetDatum(
 								 originalAggregate->aggfnoid), false, true);
@@ -2808,8 +2803,6 @@ WorkerAggregateExpressionList(Aggref *originalAggregate,
 	HeapTuple aggTuple;
 	Form_pg_aggregate aggform;
 	Oid combine;
-	Oid serial = InvalidOid;
-	Oid deserial = InvalidOid;
 
 	aggTuple = SearchSysCache1(AGGFNOID,
 							   ObjectIdGetDatum(originalAggregate->aggfnoid));
@@ -2823,11 +2816,6 @@ WorkerAggregateExpressionList(Aggref *originalAggregate,
 	{
 		aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);
 		combine = aggform->aggcombinefn;
-		if (combine != InvalidOid && originalAggregate->aggtranstype == INTERNALOID)
-		{
-			serial = aggform->aggserialfn;
-			deserial = aggform->aggdeserialfn;
-		}
 		ReleaseSysCache(aggTuple);
 	}
 
@@ -2840,6 +2828,8 @@ WorkerAggregateExpressionList(Aggref *originalAggregate,
 		Oid workerPartialId = AggregateFunctionOidWithoutInput(
 			WORKER_PARTIAL_AGGREGATE_NAME);
 
+		elog(WARNING, "worker_partial_agg %d %d", workerPartialId,
+			 originalAggregate->aggfnoid);
 		aggparam = makeConst(OIDOID, -1, InvalidOid, sizeof(Oid), ObjectIdGetDatum(
 								 originalAggregate->aggfnoid), false, true);
 		aggArguments = list_make1(makeTargetEntry((Expr *) aggparam, 1, NULL, false));
@@ -2854,7 +2844,7 @@ WorkerAggregateExpressionList(Aggref *originalAggregate,
 		/* worker_partial_agg(agg, ...args) */
 		newWorkerAggregate = makeNode(Aggref);
 		newWorkerAggregate->aggfnoid = workerPartialId;
-		newWorkerAggregate->aggtype = originalAggregate->aggtype;
+		newWorkerAggregate->aggtype = BYTEAOID;
 		newWorkerAggregate->args = aggArguments;
 		newWorkerAggregate->aggkind = AGGKIND_NORMAL;
 		newWorkerAggregate->aggfilter = originalAggregate->aggfilter;

src/backend/distributed/utils/aggregate_utils.c

@@ -4,13 +4,14 @@
 #include "catalog/pg_aggregate.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
+#include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
 #include "fmgr.h"
 
-PG_FUNCTION_INFO_V1(stypebox_serialize);
+PG_FUNCTION_INFO_V1(citus_stype_serialize);
-PG_FUNCTION_INFO_V1(stypebox_deserialize);
+PG_FUNCTION_INFO_V1(citus_stype_deserialize);
-PG_FUNCTION_INFO_V1(stypebox_combine);
+PG_FUNCTION_INFO_V1(citus_stype_combine);
 PG_FUNCTION_INFO_V1(worker_partial_agg_sfunc);
 PG_FUNCTION_INFO_V1(worker_partial_agg_ffunc);
 PG_FUNCTION_INFO_V1(coord_combine_agg_sfunc);
@@ -69,12 +70,40 @@ get_typeform(Oid oid, Form_pg_type *form)
 }
 
 
+/*
+ * See GetAggInitVal from pg's nodeAgg.c
+ */
+static void
+InitializeStypeBox(StypeBox *box, HeapTuple aggTuple, Oid transtype)
+{
+	Datum textInitVal = SysCacheGetAttr(AGGFNOID, aggTuple,
+										Anum_pg_aggregate_agginitval,
+										&box->value_null);
+	if (box->value_null)
+	{
+		box->value = (Datum) 0;
+	}
+	else
+	{
+		Oid typinput,
+			typioparam;
+		char *strInitVal;
+
+		getTypeInputInfo(transtype, &typinput, &typioparam);
+		strInitVal = TextDatumGetCString(textInitVal);
+		box->value = OidInputFunctionCall(typinput, strInitVal,
+										  typioparam, -1);
+		pfree(strInitVal);
+	}
+}
+
+
 /*
  * (box) -> bytea
  * return bytes(box.agg.oid, box.agg.serial(box.value))
  */
 Datum
-stypebox_serialize(PG_FUNCTION_ARGS)
+citus_stype_serialize(PG_FUNCTION_ARGS)
 {
 	FunctionCallInfoData inner_fcinfodata;
 	FunctionCallInfo inner_fcinfo = &inner_fcinfodata;
@@ -93,12 +122,14 @@ stypebox_serialize(PG_FUNCTION_ARGS)
 	Size realbyteslen;
 	Datum result;
 
+	elog(WARNING, "citus_stype_serialize");
+
 	aggtuple = get_aggform(box->agg, &aggform);
 	serial = aggform->aggserialfn;
 	transtype = aggform->aggtranstype;
 	ReleaseSysCache(aggtuple);
 
-	if (serial != InvalidOid)
+	if (serial == InvalidOid)
 	{
 		/* TODO do we have to fallback to output/receive if not set? */
 		/* ie is it possible for send/recv to be unset? */
@@ -107,6 +138,8 @@ stypebox_serialize(PG_FUNCTION_ARGS)
 		ReleaseSysCache(transtypetuple);
 	}
 
+	Assert(serial != InvalidOid);
+
 	fmgr_info(serial, info);
 	if (info->fn_strict && box->value_null)
 	{
@@ -157,7 +190,7 @@ stypebox_serialize(PG_FUNCTION_ARGS)
  * return box
  */
 Datum
-stypebox_deserialize(PG_FUNCTION_ARGS)
+citus_stype_deserialize(PG_FUNCTION_ARGS)
 {
 	StypeBox *box;
 	bytea *bytes = PG_GETARG_BYTEA_PP(0);
@@ -174,6 +207,8 @@ stypebox_deserialize(PG_FUNCTION_ARGS)
 	StringInfoData buf;
 	bool value_null;
 
+	elog(WARNING, "citus_stype_deserialize");
+
 	memcpy(&agg, VARDATA(bytes), sizeof(Oid));
 	memcpy(&value_null, VARDATA(bytes) + sizeof(Oid), sizeof(bool));
 
@@ -198,6 +233,7 @@ stypebox_deserialize(PG_FUNCTION_ARGS)
 
 		inner_bytes = PG_GETARG_BYTEA_P_SLICE(0, sizeof(Oid), VARSIZE(bytes) -
 											  sizeof(Oid));
+		elog(WARNING, "deserial %d", VARSIZE(inner_bytes));
 		fmgr_info(deserial, &fdeserialinfo);
 		InitFunctionCallInfoData(fdeserial_callinfodata, &fdeserialinfo, 2,
 								 fcinfo->fncollation, fcinfo->context,
@@ -209,6 +245,13 @@ stypebox_deserialize(PG_FUNCTION_ARGS)
 		box->value = FunctionCallInvoke(&fdeserial_callinfodata);
 		box->value_null = fdeserial_callinfodata.isnull;
 	}
+
+	/* TODO Correct null handling */
+	else if (value_null)
+	{
+		box->value = (Datum) 0;
+		box->value_null = true;
+	}
 	else
 	{
 		transtypetuple = get_typeform(transtype, &transtypeform);
@@ -222,7 +265,6 @@ stypebox_deserialize(PG_FUNCTION_ARGS)
 							   VARSIZE(bytes) - VARHDRSZ - sizeof(Oid) - sizeof(bool));
 
 		box->value = OidReceiveFunctionCall(recv, &buf, ioparam, -1);
-		box->value_null = value_null;
 	}
 
 	PG_RETURN_POINTER(box);
@@ -235,7 +277,7 @@ stypebox_deserialize(PG_FUNCTION_ARGS)
  * return box
  */
 Datum
-stypebox_combine(PG_FUNCTION_ARGS)
+citus_stype_combine(PG_FUNCTION_ARGS)
 {
 	StypeBox *box1 = NULL;
 	StypeBox *box2 = NULL;
@@ -246,6 +288,8 @@ stypebox_combine(PG_FUNCTION_ARGS)
 	HeapTuple aggtuple;
 	Form_pg_aggregate aggform;
 
+	elog(WARNING, "citus_stype_combine");
+
 	if (!PG_ARGISNULL(0))
 	{
 		box1 = (StypeBox *) PG_GETARG_POINTER(0);
@@ -315,38 +359,56 @@ Datum
 worker_partial_agg_sfunc(PG_FUNCTION_ARGS)
 {
 	StypeBox *box;
+	Form_pg_aggregate aggform;
+	HeapTuple aggtuple;
+	Oid aggsfunc;
 	FunctionCallInfoData inner_fcinfodata;
 	FunctionCallInfo inner_fcinfo = &inner_fcinfodata;
 	FmgrInfo info;
 	int i;
-	if (PG_ARGISNULL(0))
+	bool is_initial_call = PG_ARGISNULL(0);
+
+	elog(WARNING, "worker_partial_agg_sfunc");
+
+	if (is_initial_call)
 	{
 		box = palloc(sizeof(StypeBox));
 		box->agg = PG_GETARG_OID(1);
-		box->value = (Datum) 0;
-		box->value_null = true;
 	}
 	else
 	{
 		box = (StypeBox *) PG_GETARG_POINTER(0);
 		Assert(box->agg == PG_GETARG_OID(1));
 	}
-	fmgr_info(box->agg, &info);
+
+	aggtuple = get_aggform(box->agg, &aggform);
+	aggsfunc = aggform->aggtransfn;
+	if (is_initial_call)
+	{
+		InitializeStypeBox(box, aggtuple, aggform->aggtranstype);
+	}
+	ReleaseSysCache(aggtuple);
+
+	fmgr_info(aggsfunc, &info);
 	InitFunctionCallInfoData(*inner_fcinfo, &info, fcinfo->nargs - 1, fcinfo->fncollation,
 							 fcinfo->context, fcinfo->resultinfo);
 	if (info.fn_strict)
 	{
-		if (box->value_null)
-		{
-			PG_RETURN_NULL();
-		}
 		for (i = 2; i < PG_NARGS(); i++)
 		{
 			if (PG_ARGISNULL(i))
 			{
-				PG_RETURN_NULL();
+				elog(WARNING, "\tworker sfunc retnull %i", i);
+				PG_RETURN_POINTER(box);
 			}
 		}
+		if (box->value_null)
+		{
+			elog(WARNING, "\tworker sfunc seed");
+			box->value = PG_GETARG_DATUM(2);
+			box->value_null = false;
+			PG_RETURN_POINTER(box);
+		}
 	}
 
 	/* Deal with memory management juggling (see executor/nodeAgg) */
@@ -358,6 +420,9 @@ worker_partial_agg_sfunc(PG_FUNCTION_ARGS)
 		   (inner_fcinfo->nargs - 1));
 	box->value = FunctionCallInvoke(inner_fcinfo);
 	box->value_null = inner_fcinfo->isnull;
+
+	elog(WARNING, "\tworker sfunc null: %d", box->value_null);
+
 	PG_RETURN_POINTER(box);
 }
 
@@ -374,16 +439,37 @@ worker_partial_agg_ffunc(PG_FUNCTION_ARGS)
 	FmgrInfo info;
 	StypeBox *box = (StypeBox *) PG_GETARG_POINTER(0);
 	HeapTuple aggtuple;
+	HeapTuple transtypetuple;
 	Form_pg_aggregate aggform;
+	Form_pg_type transtypeform;
 	Oid serial;
+	Oid transtype;
 	Datum result;
 
+	elog(WARNING, "worker_partial_agg_ffunc %p", box);
+
+	if (box == NULL)
+	{
+		PG_RETURN_NULL();
+	}
+
 	aggtuple = get_aggform(box->agg, &aggform);
 	serial = aggform->aggserialfn;
+	transtype = aggform->aggtranstype;
 	ReleaseSysCache(aggtuple);
 
-	if (serial != InvalidOid)
+	if (serial == InvalidOid)
 	{
+		/* TODO do we have to fallback to output/receive if not set? */
+		/* ie is it possible for send/recv to be unset? */
+		transtypetuple = get_typeform(transtype, &transtypeform);
+		serial = transtypeform->typsend;
+		ReleaseSysCache(transtypetuple);
+	}
+
+	Assert(serial != InvalidOid);
+
+	elog(WARNING, "calling serial %d", serial);
 	fmgr_info(serial, &info);
 	if (info.fn_strict && box->value_null)
 	{
@@ -394,28 +480,19 @@ worker_partial_agg_ffunc(PG_FUNCTION_ARGS)
 	inner_fcinfo->arg[0] = box->value;
 	inner_fcinfo->argnull[0] = box->value_null;
 	result = FunctionCallInvoke(inner_fcinfo);
+	elog(WARNING, "& done %d", VARSIZE(DatumGetByteaPP(result)));
 	if (inner_fcinfo->isnull)
 	{
 		PG_RETURN_NULL();
 	}
 	PG_RETURN_DATUM(result);
-	}
-	else
-	{
-		if (box->value_null)
-		{
-			PG_RETURN_NULL();
-		}
-		PG_RETURN_DATUM(box->value);
-	}
 }
 
 
 /*
- * (box, agg, valbytes|value) -> box
+ * (box, agg, valbytes) -> box
  * box->agg = agg
- * if agg.deserialize: box->value = agg.combine(box->value, agg.deserialize(valbytes))
+ * box->value = agg.combine(box->value, agg.deserialize(valbytes))
- * else: box->value = agg.combine(box->value, value)
  * return box
  */
 Datum
@@ -425,13 +502,19 @@ coord_combine_agg_sfunc(PG_FUNCTION_ARGS)
 	FunctionCallInfo inner_fcinfo = &inner_fcinfodata;
 	FmgrInfo info;
 	HeapTuple aggtuple;
+	HeapTuple transtypetuple;
 	Form_pg_aggregate aggform;
+	Form_pg_type transtypeform;
 	Oid combine;
 	Oid deserial;
+	Oid transtype;
+	Oid ioparam;
 	Datum value;
 	bool value_null;
 	StypeBox *box;
 
+	elog(WARNING, "coord_combine_agg_sfunc");
+
 	if (PG_ARGISNULL(0))
 	{
 		box = palloc(sizeof(StypeBox));
@@ -445,9 +528,12 @@ coord_combine_agg_sfunc(PG_FUNCTION_ARGS)
 		Assert(box->agg == PG_GETARG_OID(1));
 	}
 
+	elog(WARNING, "\tbox->agg = %u", box->agg);
+
 	aggtuple = get_aggform(box->agg, &aggform);
 	deserial = aggform->aggdeserialfn;
 	combine = aggform->aggcombinefn;
+	transtype = aggform->aggtranstype;
 	ReleaseSysCache(aggtuple);
 
 	value_null = PG_ARGISNULL(2);
@@ -472,7 +558,41 @@ coord_combine_agg_sfunc(PG_FUNCTION_ARGS)
 	}
 	else
 	{
-		value = value_null ? (Datum) 0 : PG_GETARG_DATUM(2);
+		transtypetuple = get_typeform(transtype, &transtypeform);
+		ioparam = getTypeIOParam(transtypetuple);
+		deserial = transtypeform->typreceive;
+		ReleaseSysCache(transtypetuple);
+
+		fmgr_info(deserial, &info);
+		if (!value_null || !info.fn_strict)
+		{
+			StringInfoData buf;
+
+			if (!value_null)
+			{
+				bytea *data = PG_GETARG_BYTEA_PP(2);
+				initStringInfo(&buf);
+				appendBinaryStringInfo(&buf, (char *) VARDATA(data), VARSIZE(data) -
+									   VARHDRSZ);
+				elog(WARNING, "\treceive %d", buf.len);
+			}
+
+			InitFunctionCallInfoData(*inner_fcinfo, &info, 3, fcinfo->fncollation,
+									 fcinfo->context, fcinfo->resultinfo);
+			inner_fcinfo->arg[0] = PointerGetDatum(value_null ? NULL : &buf);
+			inner_fcinfo->arg[1] = ObjectIdGetDatum(ioparam);
+			inner_fcinfo->arg[2] = Int32GetDatum(-1); /* typmod */
+			inner_fcinfo->argnull[0] = value_null;
+			inner_fcinfo->argnull[1] = false;
+			inner_fcinfo->argnull[2] = false;
+
+			value = FunctionCallInvoke(inner_fcinfo);
+			value_null = inner_fcinfo->isnull;
+		}
+		else
+		{
+			value = (Datum) 0;
+		}
 	}
 
 	fmgr_info(combine, &info);
@@ -481,6 +601,7 @@ coord_combine_agg_sfunc(PG_FUNCTION_ARGS)
 	{
 		if (box->value_null)
 		{
+			elog(WARNING, "\tbox null");
 			if (value_null)
 			{
 				PG_RETURN_NULL();
@@ -491,10 +612,12 @@ coord_combine_agg_sfunc(PG_FUNCTION_ARGS)
 		}
 		if (value_null)
 		{
+			elog(WARNING, "\tvalue null");
 			PG_RETURN_POINTER(box);
 		}
 	}
 
+	elog(WARNING, "\tcombine %u", box->agg);
 	InitFunctionCallInfoData(*inner_fcinfo, &info, 2, fcinfo->fncollation,
 							 fcinfo->context, fcinfo->resultinfo);
 	inner_fcinfo->arg[0] = box->value;
@@ -530,6 +653,13 @@ coord_combine_agg_ffunc(PG_FUNCTION_ARGS)
 	bool final_strict;
 	int i;
 
+	elog(WARNING, "coord_combine_agg_ffunc %p", box);
+
+	if (box == NULL)
+	{
+		PG_RETURN_NULL();
+	}
+
 	aggtuple = get_aggform(box->agg, &aggform);
 	ffunc = aggform->aggfinalfn;
 	fextra = aggform->aggfinalextra;