(testing) prototype for async ptrack map file reading #2

Author: kulaginm

Makefile

@@ -20,3 +20,6 @@ top_builddir = ../..
 include $(top_builddir)/src/Makefile.global
 include $(top_srcdir)/contrib/contrib-global.mk
 endif
+
+engine.o: engine.h
+

engine.c

@@ -126,12 +126,13 @@ ptrackCleanFiles(void)
 #endif
 
 #ifndef PTRACK_USE_AIO
+#ifndef PTRACK_READ_CHUNK
 static bool
 ptrackMapReadFromFileSync(const char *ptrack_path)
 {
 	instr_time	func_start, func_end, crc_start, func_time, read_time, crc_time;
 
-	elog(LOG, "ptrack read map (sync version): start, ptrack_actual_size %zu bytes", PtrackActualSize);
+	elog(LOG, "ptrack read map (sync greedy version): start, ptrack_actual_size %zu bytes", PtrackActualSize);
 	INSTR_TIME_SET_CURRENT(func_start);
 
 	/* Do actual file read */
@@ -238,10 +239,144 @@ ptrackMapReadFromFileSync(const char *ptrack_path)
 	INSTR_TIME_ACCUM_DIFF(read_time, crc_start, func_start);
 	INSTR_TIME_SET_ZERO(crc_time);
 	INSTR_TIME_ACCUM_DIFF(crc_time, func_end, crc_start);
-	elog(LOG, "ptrack read map (sync version): end. Timings (microseconds): file io time = %lu, crc time = %lu, overall time = %lu", 
+	elog(LOG, "ptrack read map (sync greedy version): end. Timings (microseconds): file io time = %lu, crc time = %lu, overall time = %lu",
 			INSTR_TIME_GET_MICROSEC(read_time), INSTR_TIME_GET_MICROSEC(crc_time), INSTR_TIME_GET_MICROSEC(func_time));
 	return true;
 }
+#else
+static bool
+ptrackMapReadFromFileSync(const char *ptrack_path)
+{
+	instr_time	func_start, func_end, func_time,
+				read_start, read_end, read_time,
+				crc_start, crc_end, crc_time;
+	int			ptrack_fd;
+	size_t		readed = 0;
+	size_t		summed = 0;
+	pg_crc32c	crc;
+	pg_crc32c  *file_crc;
+
+	elog(LOG, "ptrack read map (sync non-greedy version): start, ptrack_actual_size %zu bytes, PTRACK_READ_CHUNK %zu bytes",
+			PtrackActualSize, (size_t) PTRACK_READ_CHUNK);
+	INSTR_TIME_SET_ZERO(func_time);
+	INSTR_TIME_SET_ZERO(read_time);
+	INSTR_TIME_SET_ZERO(crc_time);
+	INSTR_TIME_SET_CURRENT(func_start);
+
+	INSTR_TIME_SET_CURRENT(crc_start);
+	INIT_CRC32C(crc);
+	file_crc = (pg_crc32c *) ((char *) ptrack_map + PtrackCrcOffset);
+	INSTR_TIME_SET_CURRENT(crc_end);
+	INSTR_TIME_ACCUM_DIFF(crc_time, crc_end, crc_start);
+
+	INSTR_TIME_SET_CURRENT(read_start);
+	ptrack_fd = BasicOpenFile(ptrack_path, O_RDWR | PG_BINARY);
+	if (ptrack_fd < 0)
+		elog(ERROR, "ptrack read map: failed to open map file \"%s\": %m", ptrack_path);
+	INSTR_TIME_SET_CURRENT(read_end);
+	INSTR_TIME_ACCUM_DIFF(read_time, read_end, read_start);
+
+	do
+	{
+		ssize_t last_readed;
+
+		INSTR_TIME_SET_CURRENT(read_start);
+		last_readed = read(ptrack_fd, (char *) ptrack_map + readed, Min(PTRACK_READ_CHUNK, PtrackActualSize - readed));
+
+		if (last_readed > 0)
+		{
+			elog(DEBUG1, "ptrack read map: read: offset = %zu, nbytes = %zu, readed = %zi",
+					readed, Min((size_t) PTRACK_READ_CHUNK, PtrackActualSize - readed), last_readed);
+			readed += last_readed;
+		}
+		else if (last_readed == 0)
+		{
+			/*
+			 * We don't try to read more that PtrackActualSize and
+			 * file size was already checked in ptrackMapInit()
+			 */
+			elog(ERROR, "ptrack read map: unexpected end of file while reading map file \"%s\", expected to read %zu, but read only %zu bytes",
+						ptrack_path, PtrackActualSize, readed);
+		}
+		else if (last_readed < 0 && errno != EINTR)
+		{
+			ereport(WARNING,
+					(errcode_for_file_access(),
+					 errmsg("ptrack read map: could not read map file \"%s\": %m", ptrack_path)));
+			close(ptrack_fd);
+			return false;
+		}
+		INSTR_TIME_SET_CURRENT(read_end);
+		INSTR_TIME_ACCUM_DIFF(read_time, read_end, read_start);
+
+		if (last_readed > 0)
+		{
+			size_t sum_chunk_size = Min(last_readed, PtrackCrcOffset - summed);
+			INSTR_TIME_SET_CURRENT(crc_start);
+			elog(DEBUG1, "ptrack read map: COMP_CRC32C: offset = %zu, nbytes = %zu",
+							summed, sum_chunk_size);
+			COMP_CRC32C(crc, (char *) ptrack_map + summed, sum_chunk_size);
+			summed += sum_chunk_size;
+			INSTR_TIME_SET_CURRENT(crc_end);
+			INSTR_TIME_ACCUM_DIFF(crc_time, crc_end, crc_start);
+		}
+	} while (readed < PtrackActualSize);
+
+	INSTR_TIME_SET_CURRENT(read_start);
+	close(ptrack_fd);
+	INSTR_TIME_SET_CURRENT(read_end);
+	INSTR_TIME_ACCUM_DIFF(read_time, read_end, read_start);
+
+
+	INSTR_TIME_SET_CURRENT(crc_start);
+	/* Check PTRACK_MAGIC */
+	if (strcmp(ptrack_map->magic, PTRACK_MAGIC) != 0)
+	{
+		elog(WARNING, "ptrack read map: wrong map format of file \"%s\"", ptrack_path);
+		return false;
+	}
+
+	/* Check ptrack version inside old ptrack map */
+	if (ptrack_map->version_num != PTRACK_MAP_FILE_VERSION_NUM)
+	{
+		ereport(WARNING,
+				(errcode(ERRCODE_DATA_CORRUPTED),
+				 errmsg("ptrack read map: map format version %d in the file \"%s\" is incompatible with file format of extension %d",
+						ptrack_map->version_num, ptrack_path, PTRACK_MAP_FILE_VERSION_NUM),
+				 errdetail("Deleting file \"%s\" and reinitializing ptrack map.", ptrack_path)));
+		return false;
+	}
+
+	/* Check CRC */
+	{
+		FIN_CRC32C(crc);
+
+		/*
+		 * Read ptrack map values without atomics during initialization, since
+		 * postmaster is the only user right now.
+		 */
+		elog(DEBUG1, "ptrack read map: crc %u, file_crc %u, init_lsn %X/%X",
+			 crc, *file_crc, (uint32) (ptrack_map->init_lsn.value >> 32), (uint32) ptrack_map->init_lsn.value);
+
+		if (!EQ_CRC32C(*file_crc, crc))
+		{
+			ereport(WARNING,
+					(errcode(ERRCODE_DATA_CORRUPTED),
+					 errmsg("ptrack read map: incorrect checksum of file \"%s\"", ptrack_path),
+					 errdetail("Deleting file \"%s\" and reinitializing ptrack map.", ptrack_path)));
+			return false;
+		}
+	}
+	INSTR_TIME_SET_CURRENT(crc_end);
+	INSTR_TIME_ACCUM_DIFF(crc_time, crc_end, crc_start);
+
+	INSTR_TIME_SET_CURRENT(func_end);
+	INSTR_TIME_ACCUM_DIFF(func_time, func_end, func_start);
+	elog(LOG, "ptrack read map (sync non-greedy version): end. Timings (microseconds): file io time = %lu, crc time = %lu, overall time = %lu", 
+			INSTR_TIME_GET_MICROSEC(read_time), INSTR_TIME_GET_MICROSEC(crc_time), INSTR_TIME_GET_MICROSEC(func_time));
+	return true;
+}
+#endif
 #endif
 
 #ifdef PTRACK_USE_AIO

engine.h

@@ -92,10 +92,13 @@ typedef PtrackMapHdr * PtrackMap;
 /* async io section*/
 
 /* use aio ptrack map read if defined */
-#define PTRACK_USE_AIO
+//#define PTRACK_USE_AIO
 
 /* size of one async read operation (bytes) */
-#define PTRACK_AIO_READ_CHUNK 1024*1024
+#define PTRACK_AIO_READ_CHUNK 2*1024*1024
+
+/* size of one sync read operation (bytes), or try to read whole file if undefined */
+#define PTRACK_READ_CHUNK 1024*1024
 
 /* maximum count of pending aio read operations */
 #define PTRACK_AIO_READ_QUEUE_DEPTH 4