diff --git a/src/qli/compile.cpp b/src/qli/compile.cpp
index 7e4e6231f5..709dcd8b1e 100644
--- a/src/qli/compile.cpp
+++ b/src/qli/compile.cpp
@@ -34,6 +34,7 @@
 #include "../qli/forma_proto.h"
 #include "../qli/meta_proto.h"
 #include "../jrd/dsc_proto.h"
+#include "../jrd/align.h"
 
 const USHORT PROMPT_LENGTH	= 80;
 
@@ -114,8 +115,10 @@ void CMP_alloc_temp(qli_nod* node)
 	if (node->nod_desc.dsc_address)
 		return;
 
-	qli_str* string = (qli_str*) ALLOCDV(type_str, node->nod_desc.dsc_length);
-	node->nod_desc.dsc_address = (UCHAR *) string->str_data;
+	qli_str* string = (qli_str*) ALLOCDV(type_str, node->nod_desc.dsc_length + 
+					     type_alignments[node->nod_desc.dsc_dtype]);
+	node->nod_desc.dsc_address = (UCHAR *) FB_ALIGN((FB_UINT64)(U_IPTR)(string->str_data), type_alignments[node->nod_desc.dsc_dtype]);
+	QLI_validate_desc(node->nod_desc);
 }
 
 
@@ -428,6 +431,7 @@ static qli_nod* compile_edit( qli_nod* node, qli_req* request)
 	node->nod_desc.dsc_dtype = dtype_blob;
 	node->nod_desc.dsc_length = 8;
 	node->nod_desc.dsc_address = (UCHAR *) & node->nod_arg[e_edt_id1];
+	QLI_validate_desc(node->nod_desc);
 
 	return node;
 }
@@ -663,6 +667,7 @@ static qli_nod* compile_expression( qli_nod* node, qli_req* request, bool intern
 	case nod_variable:
 		field = (qli_fld*) node->nod_arg[e_fld_field];
 		node->nod_desc.dsc_address = field->fld_data;
+		QLI_validate_desc(node->nod_desc);
 		make_descriptor(node, &node->nod_desc);
 		if (internal_flag)
 		{
@@ -1121,6 +1126,7 @@ static qli_nod* compile_prompt( qli_nod* node)
 	node->nod_desc.dsc_dtype = dtype_varying;
 	node->nod_desc.dsc_length = prompt_length;
 	node->nod_desc.dsc_address = (UCHAR *) string->str_data;
+	QLI_validate_desc(node->nod_desc);
 
 	return node;
 }
diff --git a/src/qli/dtr.cpp b/src/qli/dtr.cpp
index 4366e529bb..4456cc1245 100644
--- a/src/qli/dtr.cpp
+++ b/src/qli/dtr.cpp
@@ -54,6 +54,7 @@
 #include "../jrd/perf_proto.h"
 #include "../include/fb_exception.h"
 #include "../common/utils_proto.h"
+#include "../jrd/align.h"
 
 using MsgFormat::SafeArg;
 
@@ -662,3 +663,14 @@ static bool yes_no(USHORT number, const TEXT* arg1)
 	}
 }
 
+#ifdef DEV_BUILD
+void QLI_validate_desc(const dsc* d)
+{
+    fb_assert(d->dsc_dtype > dtype_unknown);
+    fb_assert(d->dsc_dtype < DTYPE_TYPE_MAX);
+    ULONG addr = (ULONG) (U_IPTR) (d->dsc_address);	// safely ignore higher bits even if present
+    USHORT ta = type_alignments[d->dsc_dtype];
+    if (ta > 1)
+	fb_assert((addr & (ta - 1)) == 0);
+}
+#endif
diff --git a/src/qli/dtr.h b/src/qli/dtr.h
index 1e2fbc41f2..cc47bf2540 100644
--- a/src/qli/dtr.h
+++ b/src/qli/dtr.h
@@ -536,5 +536,12 @@ EXTERN qli_req*	QLI_requests;			// Requests in statement
 
 #include "../qli/all_proto.h"
 
+#ifdef DEV_BUILD
+void QLI_validate_desc(const dsc*);
+#else
+inline void QLI_validate_desc(const dsc*) { }
+#endif
+inline void QLI_validate_desc(const dsc& d) { QLI_validate_desc(&d); }
+
 #endif // QLI_DTR_H
 
diff --git a/src/qli/eval.cpp b/src/qli/eval.cpp
index 04eff096c4..a5dddf1394 100644
--- a/src/qli/eval.cpp
+++ b/src/qli/eval.cpp
@@ -335,6 +335,7 @@ dsc* EVAL_parameter(qli_par* parameter)
 	}
 
 	desc->dsc_address = message->msg_buffer + parameter->par_offset;
+	QLI_validate_desc(desc);
 
 	return desc;
 }
diff --git a/src/qli/exe.cpp b/src/qli/exe.cpp
index cd77b0ab76..ef66930794 100644
--- a/src/qli/exe.cpp
+++ b/src/qli/exe.cpp
@@ -1063,6 +1063,7 @@ static void map_data( qli_msg* message)
 	{
 		dsc* desc = &parameter->par_desc;
 		desc->dsc_address = message->msg_buffer + parameter->par_offset;
+		QLI_validate_desc(desc);
 		qli_par* missing_parameter = parameter->par_missing;
 		if (missing_parameter) {
 			USHORT* missing_flag = (USHORT*) (message->msg_buffer +
diff --git a/src/qli/expand.cpp b/src/qli/expand.cpp
index 42990b1599..d0be6e230e 100644
--- a/src/qli/expand.cpp
+++ b/src/qli/expand.cpp
@@ -2758,6 +2758,7 @@ static qli_nod* possible_literal(qli_syntax* input,
 	constant->con_desc.dsc_dtype = dtype_text;
 	constant->con_desc.dsc_length = l;
 	constant->con_desc.dsc_address = constant->con_data;
+	QLI_validate_desc(constant->con_desc);
 	TEXT* p = (TEXT*) constant->con_data;
 	const TEXT* q = name->nam_string;
 
diff --git a/src/qli/format.cpp b/src/qli/format.cpp
index 780faab52c..3f14119812 100644
--- a/src/qli/format.cpp
+++ b/src/qli/format.cpp
@@ -401,6 +401,7 @@ qli_nod* FMT_list(qli_nod* list)
 				value->nod_desc.dsc_length = name->sym_length;
 				value->nod_desc.dsc_address = (UCHAR *) name->sym_string;
 			}
+			QLI_validate_desc(value->nod_desc);
 			column = MAX(column, value->nod_desc.dsc_length);
 			new_item->itm_picture = PIC_analyze(0, &value->nod_desc);
 		}
diff --git a/src/qli/gener.cpp b/src/qli/gener.cpp
index da44670ebc..567ff9af10 100644
--- a/src/qli/gener.cpp
+++ b/src/qli/gener.cpp
@@ -498,6 +498,7 @@ static void gen_any( qli_nod* node, qli_req* request)
 		desc.dsc_scale = 0;
 		desc.dsc_sub_type = 0;
 		desc.dsc_address = (UCHAR*) &value;
+		QLI_validate_desc(desc);
 
 		STUFF(blr_assignment);
 		value = TRUE;
@@ -1094,6 +1095,7 @@ static void gen_for( qli_nod* node, qli_req* request)
 		desc.dsc_scale = 0;
 		desc.dsc_sub_type = 0;
 		desc.dsc_address = (UCHAR*) &value;
+		QLI_validate_desc(desc);
 
 		STUFF(blr_assignment);
 		value = FALSE;
@@ -1497,8 +1499,8 @@ static void gen_request( qli_req* request)
 		STUFF(message->msg_number);
 		STUFF_WORD(message->msg_parameter);
 
-		qli_str* string = (qli_str*) ALLOCDV(type_str, message->msg_length);
-		message->msg_buffer = (UCHAR*) string->str_data;
+		qli_str* string = (qli_str*) ALLOCDV(type_str, message->msg_length + DOUBLE_ALIGN - 1);
+		message->msg_buffer = (UCHAR*) FB_ALIGN((FB_UINT64)(U_IPTR)(string->str_data), DOUBLE_ALIGN);
 
 		for (param = message->msg_parameters; param; param = param->par_next) {
 			gen_descriptor(&param->par_desc, request);
diff --git a/src/qli/meta.epp b/src/qli/meta.epp
index 43ee587ee2..3f58837644 100644
--- a/src/qli/meta.epp
+++ b/src/qli/meta.epp
@@ -3251,6 +3251,7 @@ static qli_syntax* parse_blr( UCHAR ** ptr, qli_symbol* symbol)
 		constant->con_desc.dsc_scale = scale;
 		constant->con_desc.dsc_length = length;
 		constant->con_desc.dsc_address = p = constant->con_data;
+		QLI_validate_desc(constant->con_desc);
 		if (dtype == dtype_text)
 			while (l--)
 				*p++ = BLR_BYTE;
diff --git a/src/qli/mov.cpp b/src/qli/mov.cpp
index ec86c3310d..ac410eb273 100644
--- a/src/qli/mov.cpp
+++ b/src/qli/mov.cpp
@@ -348,6 +348,7 @@ double MOVQ_date_to_double(const dsc* desc)
 		temp_desc.dsc_sub_type = 0;
 		date = temp;
 		temp_desc.dsc_address = (UCHAR *) date;
+		QLI_validate_desc(temp_desc);
 		MOVQ_move(desc, &temp_desc);
 	}
 
@@ -695,6 +696,7 @@ int MOVQ_get_string(const dsc* desc, const TEXT** address, vary* temp,
 	temp_desc.dsc_scale = 0;
 	temp_desc.dsc_dtype = dtype_varying;
 	temp_desc.dsc_sub_type = ttype_ascii;
+	QLI_validate_desc(temp_desc);
 	MOVQ_move(desc, &temp_desc);
 	*address = temp->vary_string;
 
@@ -1075,6 +1077,7 @@ static void sql_date_to_text( SLONG date[1], DSC * to)
 	desc.dsc_dtype = dtype_text;
 	desc.dsc_scale = 0;
 	desc.dsc_sub_type = ttype_ascii;
+	QLI_validate_desc(desc);
 
 	MOVQ_move(&desc, to);
 }
@@ -1114,6 +1117,7 @@ static void sql_time_to_text( ULONG date[1], DSC * to)
 	desc.dsc_dtype = dtype_text;
 	desc.dsc_scale = 0;
 	desc.dsc_sub_type = ttype_ascii;
+	QLI_validate_desc(desc);
 
 	MOVQ_move(&desc, to);
 }
@@ -1155,6 +1159,7 @@ static void timestamp_to_text( SLONG date[2], DSC * to)
 	desc.dsc_dtype = dtype_text;
 	desc.dsc_scale = 0;
 	desc.dsc_sub_type = ttype_ascii;
+	QLI_validate_desc(desc);
 
 	MOVQ_move(&desc, to);
 }
@@ -1246,6 +1251,7 @@ static void numeric_to_text(const dsc* from, dsc* to)
 	intermediate.dsc_scale = scale;
 	intermediate.dsc_sub_type = 0;
 	intermediate.dsc_address = (UCHAR *) &n;
+	QLI_validate_desc(intermediate);
 
 	MOVQ_move(from, &intermediate);
 
diff --git a/src/qli/parse.cpp b/src/qli/parse.cpp
index 515f910cd7..e64a4a6725 100644
--- a/src/qli/parse.cpp
+++ b/src/qli/parse.cpp
@@ -591,6 +591,7 @@ static qli_const* make_numeric_constant(const TEXT* string, USHORT length)
 		while (--length)
 			*p++ = *string++;
 	}
+	QLI_validate_desc(constant->con_desc);
 
 	return constant;
 }
@@ -2207,6 +2208,7 @@ static qli_const* parse_literal(void)
 		constant = (qli_const*) ALLOCDV(type_con, l);
 		constant->con_desc.dsc_dtype = dtype_text;
 		UCHAR* p = constant->con_desc.dsc_address = constant->con_data;
+		QLI_validate_desc(constant->con_desc);
 		if (constant->con_desc.dsc_length = l)
 			do {
 				*p++ = *q++;
diff --git a/src/qli/picstr.cpp b/src/qli/picstr.cpp
index 1fa47074ad..e718db63ae 100644
--- a/src/qli/picstr.cpp
+++ b/src/qli/picstr.cpp
@@ -575,6 +575,7 @@ static void edit_date( const dsc* desc, pics* picture, TEXT** output)
 	temp_desc.dsc_sub_type = 0;
 	temp_desc.dsc_length = sizeof(date);
 	temp_desc.dsc_address = (UCHAR *) date;
+	QLI_validate_desc(temp_desc);
 	MOVQ_move(desc, &temp_desc);
 
     tm times;