diff --git a/doc/README.Optimizer.txt b/doc/README.Optimizer.txt
index f9b87481ce..2f11f443ca 100644
--- a/doc/README.Optimizer.txt
+++ b/doc/README.Optimizer.txt
@@ -25,7 +25,7 @@ B) Try to deliver conjuntions made on a UNION inside every single stream.
 C) Cardinality calculation has been improved for a better estimated value.
 
 D) MERGE/SORT operation may now be generated for inner joins using equality 
-   comparsion on expressions.
+   comparison on expressions.
 
    SELECT Count(*) FROM
      Relations r
@@ -33,7 +33,7 @@ D) MERGE/SORT operation may now be generated for inner joins using equality
    WHERE
      rc.CategoryID = 3
 
-E) When a UNIQUE index can be fully matched (equality) used on a relation, use this 
+E) When a UNIQUE index used on a relation can be fully matched (equality), use this 
    index and forget any possible indexes.
 
 F) Indexed order read with an OUTER JOIN.
@@ -56,7 +56,7 @@ G) Ignore NULL values in index scan for operators other than IS NULL and Equival
    Note: This works currently only at single segment indexes.
 
 
-H) Calculate with more accurate selectivity for compound indexes which are partially 
+H) Calculate with more accuracy selectivity for compound indexes which are partially 
    matched with conjunctions. Due this we can now use cost-based approach also for 
    partially matched indexes. 
 
@@ -76,7 +76,7 @@ J) STARTING WITH can be used inside compound indexes on every segment, but only
    SELECT * FROM Relations WHERE FirstName = 'Joe' and LastName STARTING WITH 'D'
 
 K) Use AND conjunctions also inside OR conjunctions to help with matching on a 
-   compound index. The same calculation for every left and right node of a OR 
+   compound index. The same calculation for every left and right node of an OR 
    conjunction is used as for the AND conjunctions.
 
    Example:
diff --git a/src/jrd/Optimizer.cpp b/src/jrd/Optimizer.cpp
index 67cc4b671c..1a9d9a3441 100644
--- a/src/jrd/Optimizer.cpp
+++ b/src/jrd/Optimizer.cpp
@@ -1227,10 +1227,10 @@ InversionCandidate* OptimizerRetrieval::generateInversion(RecordSource** rsb)
 		// very safe at the moment, but in our case Array holds a sorted list.
 		// However SortedArray class should be updated to handle join right!
 		matches.join(invCandidate->matches);
-		size_t pos;
 		tail = optimizer->opt_conjuncts.begin();
 		for (; tail < opt_end; tail++) {
 			if (!(tail->opt_conjunct_flags & opt_conjunct_used)) {
+				size_t pos;
 				if (matches.find(tail->opt_conjunct_node, pos)) {
 					tail->opt_conjunct_flags |= opt_conjunct_matched;
 				}
diff --git a/src/jrd/isc_file.cpp b/src/jrd/isc_file.cpp
index c8bbd592c0..ff2514620a 100644
--- a/src/jrd/isc_file.cpp
+++ b/src/jrd/isc_file.cpp
@@ -1561,12 +1561,12 @@ bool Mnt::get()
 	const char* start = device;
 	
 	if (n<5)
-	{ return false;}
+	return false;
 
 	const char* iflag = strchr(device, ':');
 	if (iflag)
 	{
-		node = tstring( start , size_t(iflag-start) );
+		node = tstring( start , size_t(iflag - start) );
 		path = tstring( ++iflag );
 	}
 	else {
diff --git a/src/jrd/opt.cpp b/src/jrd/opt.cpp
index 4fcb2cd3f3..846f40bece 100644
--- a/src/jrd/opt.cpp
+++ b/src/jrd/opt.cpp
@@ -4716,10 +4716,9 @@ static RecordSource* gen_retrieval(thread_db*     tdbb,
 	const bool ods11orHigher = (dbb->dbb_ods_version >= ODS_VERSION11);
 	if (ods11orHigher && !relation->rel_file) {
 		// For ODS11 and higher databases we can use new calculations
-		InversionCandidate* candidate = NULL;
 		OptimizerRetrieval* optimizerRetrieval = FB_NEW(*tdbb->getDefaultPool()) 
 			OptimizerRetrieval(*tdbb->getDefaultPool(), opt, stream, outer_flag, inner_flag, sort_ptr);
-		candidate = optimizerRetrieval->getInversion(&rsb);
+		InversionCandidate* candidate = optimizerRetrieval->getInversion(&rsb);
 		if (candidate && candidate->inversion) {
 			inversion = candidate->inversion;			
 		}
@@ -5735,11 +5734,11 @@ static jrd_nod* get_unmapped_node(thread_db* tdbb, jrd_nod* node,
 	SET_TDBB(tdbb);
 
 	// Check if node is a mapping and if so unmap it, but
-	// only for root nodes (not contained in an other node).
+	// only for root nodes (not contained in another node).
 	// This can be expanded by checking complete expression
 	// (Then don't forget to leave aggregate-functions alone 
 	//  in case of aggregate rse)
-	// Because this is only to help using a index we keep 
+	// Because this is only to help using an index we keep 
 	// it simple.
 	if ((node->nod_type == nod_field) && 
 		((USHORT)(IPTR) node->nod_arg[e_fld_stream] == shellStream))