the new disk page cache. temporarily disabled.

DiskPageCache.cpp

@@ -0,0 +1,110 @@
+#include "gb-include.h"
+
+#include "DiskPageCache.h"
+#include "RdbCache.h"
+
+// key = 24 bytes = 192 bits
+// vvvvvvvv vvvvvvvv vvvvvvvv vvvvvvvv v = vfd = unique file handle
+// vvvvvvvv vvvvvvvv vvvvvvvv vvvvvvvv
+// ffffffff ffffffff ffffffff ffffffff f = file read offset
+// ffffffff ffffffff ffffffff ffffffff
+// bbbbbbbb bbbbbbbb bbbbbbbb bbbbbbbb b = bytes to read
+// bbbbbbbb bbbbbbbb bbbbbbbb bbbbbbbb
+
+
+DiskPageCache::DiskPageCache () {
+}
+
+DiskPageCache::~DiskPageCache() {
+	reset();
+}
+
+void DiskPageCache::reset() {
+	m_rc.reset();
+}
+
+bool DiskPageCache::init ( const char *dbname ,
+			   char rdbId,
+			   int64_t maxMem  ,
+			   int32_t pageSize ) {
+	reset();
+
+	snprintf(m_dbname,62,"pg-%s",dbname );
+	m_pageSize = pageSize;
+	m_rdbId = rdbId;
+	m_enabled = true;
+
+	// disable for now
+	return true;
+
+	return m_rc.init( maxMem ,
+			  -1 , // fixedDataSize (-1->variable)
+			  false , // supportlists?
+			  // see RdbMap.h *PAGE_SIZE. it can be 1k or 32k so
+			  // we pick 4k to be in the middle
+			  maxMem / m_pageSize , // maxCacheNodes
+			  false , // usehalfkeys?
+			  m_dbname ,
+			  false , // loadfromdisk?
+			  24 , // 24 byte key
+			  12 , // data key size?
+			  -1 ); // num ptrs max
+
+}
+
+key192_t makePCKey ( int64_t vfd ,
+		     int64_t offset ,
+		     int64_t readSize ) {
+	key192_t k;
+	k.n2 = vfd;
+	k.n1 = readSize;
+	k.n0 = offset;
+	return k;
+}
+
+char *DiskPageCache::getPages ( int64_t vfd , 
+				int64_t offset , 
+				int64_t readSize ) {
+	if ( ! m_enabled ) return NULL;
+	// disable for now
+	return NULL;
+	// make the key
+	key192_t k = makePCKey ( vfd , offset , readSize );
+	char *rec = NULL;
+	int32_t recSize;
+	bool found = m_rc.getRecord ( (collnum_t)0 , // collnum
+				      (char *)&k ,
+				      &rec ,
+				      &recSize ,
+				      true , // doCopy? for now, yes
+				      -1 , // maxAge, none, permanent vfd
+				      true , // incCounts - stats hits/misses
+				      NULL , // cachedTimeptr
+				      true ); // promote rec?
+	if ( ! found ) return NULL;
+	// sanity
+	if ( recSize != readSize ) { char *xx=NULL;*xx=0; }
+	return rec;
+}
+
+// returns true if successfully added to the cache, false otherwise
+bool DiskPageCache::addPages ( int64_t vfd , 
+			       int64_t offset , 
+			       int64_t readSize ,
+			       char   *buf ,
+			       char    niceness ) {
+	if ( ! m_enabled ) return false;
+	// disable for now
+	return true;
+	// make the key
+	key192_t k = makePCKey ( vfd , offset , readSize );
+	time_t now = getTimeLocal();
+	return m_rc.addRecord ( (collnum_t)0 , // collnum
+				(char *)&k ,
+				buf , 
+				readSize ,
+				NULL , // rec2
+				0 , // recsize2
+				now , //timestamp
+				NULL ); // return rec ptr
+}

DiskPageCache.h

@@ -0,0 +1,57 @@
+// Matt Wells, Copyright Jan 2004-2015
+
+// . now we just use RdbCache
+// . when a BigFile is first opened we assign it a unique 'vfd' (virtual fd)
+// . to make the rdbcache key we hash this vfd with the read offset and size
+
+#ifndef PAGECACHE_H
+#define PAGECACHE_H
+
+#include "RdbCache.h"
+
+class DiskPageCache {
+
+ public:
+
+	DiskPageCache();
+	~DiskPageCache();
+	void reset();
+
+	// returns false and sets g_errno if unable to alloc the memory,
+	// true otherwise
+	bool init ( const char *dbname , 
+		    char    rdbId , 
+		    int64_t maxMem ,
+		    int32_t pageSize );
+
+	// . this returns true iff the entire read was copied into
+	//   "buf" from the page cache
+	// . it will move the used pages to the head of the linked list
+	char *getPages ( int64_t  vfd , 
+			 int64_t  offset , 
+			 int64_t  readSize );
+
+	// after you read/write from/to disk, copy into the page cache
+	bool addPages  ( int64_t  vfd , 
+			 int64_t  offset , 
+			 int64_t  readSize ,
+			 char    *buf , 
+			 char     niceness );
+
+	void enableCache () { m_enabled = true ; };
+	void disableCache() { m_enabled = false; };
+	bool m_enabled;
+
+	int32_t m_pageSize;
+	char m_rdbId;
+	char m_dbname[64];
+
+	RdbCache m_rc;
+
+	int64_t getNumHits   () { return m_rc.getNumHits(); }
+	int64_t getNumMisses () { return m_rc.getNumMisses(); }
+	int64_t getMemUsed   () { return m_rc.getMemOccupied(); } 
+	int64_t getMemAlloced() { return m_rc.getMemAlloced(); } 
+};
+
+#endif