Add CachedRequestId mechanism for internal request cache.

Author: asfernandes

src/jrd/Attachment.cpp

@@ -265,6 +265,7 @@ Jrd::Attachment::Attachment(MemoryPool* pool, Database* dbb, JProvider* provider
 	  att_generators(*pool),
 	  att_internal(*pool),
 	  att_dyn_req(*pool),
+	  att_internal_cached_statements(*pool),
 	  att_dec_status(DecimalStatus::DEFAULT),
 	  att_charsets(*pool),
 	  att_charset_ids(*pool),
@@ -681,9 +682,15 @@ Request* Jrd::Attachment::findSystemRequest(thread_db* tdbb, USHORT id, USHORT w
 
 	//Database::CheckoutLockGuard guard(this, dbb_cmp_clone_mutex);
 
-	fb_assert(which == IRQ_REQUESTS || which == DYN_REQUESTS);
+	fb_assert(which == IRQ_REQUESTS || which == DYN_REQUESTS || which == CACHED_REQUESTS);
 
-	Statement* statement = (which == IRQ_REQUESTS ? att_internal[id] : att_dyn_req[id]);
+	if (which == CACHED_REQUESTS && id >= att_internal_cached_statements.getCount())
+		att_internal_cached_statements.grow(id + 1);
+
+	Statement* statement =
+		which == IRQ_REQUESTS ? att_internal[id] :
+		which == DYN_REQUESTS ? att_dyn_req[id] :
+		att_internal_cached_statements[id];
 
 	if (!statement)
 		return NULL;

src/jrd/Attachment.h

@@ -666,6 +666,7 @@ class Attachment : public pool_alloc<type_att>
 
 	Firebird::Array<Statement*>	att_internal;			// internal statements
 	Firebird::Array<Statement*>	att_dyn_req;			// internal dyn statements
+	Firebird::Array<Statement*>	att_internal_cached_statements;		// internal cached statements
 	Firebird::ICryptKeyCallback*	att_crypt_callback;		// callback for DB crypt
 	Firebird::DecimalStatus			att_dec_status;			// error handling and rounding
 

src/jrd/exe.cpp

@@ -1897,8 +1897,15 @@ void AutoCacheRequest::cacheRequest()
 	thread_db* tdbb = JRD_get_thread_data();
 	Attachment* att = tdbb->getAttachment();
 
-	Statement** stmt = which == IRQ_REQUESTS ? &att->att_internal[id] :
-		which == DYN_REQUESTS ? &att->att_dyn_req[id] : nullptr;
+	if (which == CACHED_REQUESTS && id >= att->att_internal_cached_statements.getCount())
+		att->att_internal_cached_statements.grow(id + 1);
+
+	Statement** stmt =
+		which == IRQ_REQUESTS ? &att->att_internal[id] :
+		which == DYN_REQUESTS ? &att->att_dyn_req[id] :
+		which == CACHED_REQUESTS ? &att->att_internal_cached_statements[id] :
+		nullptr;
+
 	if (!stmt)
 	{
 		fb_assert(false);

src/jrd/exe_proto.h

@@ -25,6 +25,7 @@
 #define JRD_EXE_PROTO_H
 
 #include "../jrd/cmp_proto.h"
+#include <atomic>
 
 namespace Jrd {
 	class Request;
@@ -58,6 +59,29 @@ void EXE_unwind(Jrd::thread_db*, Jrd::Request*);
 
 namespace Jrd
 {
+	class CachedRequestId
+	{
+	public:
+		CachedRequestId()
+			: id(generator++)
+		{
+			fb_assert(id <= MAX_USHORT);
+		}
+
+		CachedRequestId(const CachedRequestId&) = delete;
+		CachedRequestId& operator=(const CachedRequestId&) = delete;
+
+	public:
+		USHORT getId() const
+		{
+			return id;
+		}
+
+	private:
+		unsigned id;
+		static inline std::atomic<unsigned> generator;
+	};
+
 	// ASF: To make this class MT-safe in SS for v3, it should be AutoCacheRequest::release job to
 	// inform CMP that the request is available for subsequent usage.
 	class AutoCacheRequest
@@ -70,6 +94,13 @@ namespace Jrd
 		{
 		}
 
+		AutoCacheRequest(thread_db* tdbb, const CachedRequestId& cachedRequestId)
+			: id(cachedRequestId.getId()),
+			  which(CACHED_REQUESTS),
+			  request(tdbb->getAttachment()->findSystemRequest(tdbb, id, which))
+		{
+		}
+
 		AutoCacheRequest()
 			: id(0),
 			  which(0),
@@ -92,6 +123,15 @@ namespace Jrd
 			request = tdbb->getAttachment()->findSystemRequest(tdbb, id, which);
 		}
 
+		void reset(thread_db* tdbb, const CachedRequestId& cachedRequestId)
+		{
+			release();
+
+			id = cachedRequestId.getId();
+			which = CACHED_REQUESTS;
+			request = tdbb->getAttachment()->findSystemRequest(tdbb, id, which);
+		}
+
 		void compile(thread_db* tdbb, const UCHAR* blr, ULONG blrLength)
 		{
 			if (request)

src/jrd/jrd.h

@@ -205,8 +205,10 @@ class TrigVector : public Firebird::ObjectsArray<Trigger>
 //
 // Flags to indicate normal internal requests vs. dyn internal requests
 //
+// IRQ_REQUESTS and DYN_REQUESTS are deprecated
 const int IRQ_REQUESTS				= 1;
 const int DYN_REQUESTS				= 2;
+const int CACHED_REQUESTS			= 3;
 
 
 // Procedure block