greenplumn cdbappendonlystorageread 源码
greenplumn cdbappendonlystorageread 代码
文件路径：/src/backend/cdb/cdbappendonlystorageread.c
/*-------------------------------------------------------------------------
*
* cdbappendonlystorageread.c
*
* Portions Copyright (c) 2007-2009, Greenplum inc
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
*
*
* IDENTIFICATION
* src/backend/cdb/cdbappendonlystorageread.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#ifndef WIN32
#include <sys/fcntl.h>
#else
#include <io.h>
#endif
#include <sys/file.h>
#include <unistd.h>
#include "catalog/pg_compression.h"
#include "cdb/cdbappendonlystorage.h"
#include "cdb/cdbappendonlystoragelayer.h"
#include "cdb/cdbappendonlystorageformat.h"
#include "cdb/cdbappendonlystorageread.h"
#include "storage/gp_compress.h"
#include "utils/guc.h"
/*----------------------------------------------------------------
* Initialization
*----------------------------------------------------------------
*/
/*
* Initialize AppendOnlyStorageRead.
*
* The AppendOnlyStorageRead data structure is initialized once for a read
* "session" and can be used to read Append-Only Storage Blocks from 1 or
* more segment files.
*
* The current file to read to is opened with the
* AppendOnlyStorageRead_OpenFile routine.
*
* storageRead - data structure to initialize
* memoryContext - memory context to use for buffers and other memory
* needs. When NULL, the current memory context is used.
* maxBufferLen - maximum Append-Only Storage Block length including all
* storage headers.
* relationName - name of the relation to use in system logging and
* error messages.
* title - A phrase that better describes the purpose of this open.
* The caller manages the storage for this.
* storageAttributes - Append-Only Storage Attributes from relation creation.
*/
void
AppendOnlyStorageRead_Init(AppendOnlyStorageRead *storageRead,
MemoryContext memoryContext,
int32 maxBufferLen,
char *relationName,
char *title,
AppendOnlyStorageAttributes *storageAttributes)
{
uint8 *memory;
int32 memoryLen;
MemoryContext oldMemoryContext;
Assert(storageRead != NULL);
/* UNDONE: Range check maxBufferLen */
Assert(relationName != NULL);
Assert(storageAttributes != NULL);
/* UNDONE: Range check fields in storageAttributes */
MemSet(storageRead, 0, sizeof(AppendOnlyStorageRead));
storageRead->maxBufferLen = maxBufferLen;
if (memoryContext == NULL)
storageRead->memoryContext = CurrentMemoryContext;
else
storageRead->memoryContext = memoryContext;
oldMemoryContext = MemoryContextSwitchTo(storageRead->memoryContext);
memcpy(&storageRead->storageAttributes,
storageAttributes,
sizeof(AppendOnlyStorageAttributes));
storageRead->relationName = pstrdup(relationName);
storageRead->title = title;
storageRead->minimumHeaderLen =
AppendOnlyStorageFormat_RegularHeaderLenNeeded(
storageRead->storageAttributes.checksum);
/*
* Initialize BufferedRead.
*/
storageRead->largeReadLen = 2 * storageRead->maxBufferLen;
memoryLen = BufferedReadMemoryLen(storageRead->maxBufferLen,
storageRead->largeReadLen);
Assert(CurrentMemoryContext == storageRead->memoryContext);
memory = (uint8 *) palloc(memoryLen);
BufferedReadInit(&storageRead->bufferedRead,
memory,
memoryLen,
storageRead->maxBufferLen,
storageRead->largeReadLen,
relationName);
elogif(Debug_appendonly_print_scan || Debug_appendonly_print_read_block, LOG,
"Append-Only Storage Read initialize for table '%s' "
"(compression = %s, compression level %d, maximum buffer length %d, large read length %d)",
storageRead->relationName,
(storageRead->storageAttributes.compress ? "true" : "false"),
storageRead->storageAttributes.compressLevel,
storageRead->maxBufferLen,
storageRead->largeReadLen);
storageRead->file = -1;
storageRead->formatVersion = -1;
MemoryContextSwitchTo(oldMemoryContext);
storageRead->isActive = true;
}
/*
* Return (read-only) pointer to relation name.
*/
char *
AppendOnlyStorageRead_RelationName(AppendOnlyStorageRead *storageRead)
{
Assert(storageRead != NULL);
Assert(storageRead->isActive);
return storageRead->relationName;
}
/*
* Return (read-only) pointer to relation name.
*/
char *
AppendOnlyStorageRead_SegmentFileName(AppendOnlyStorageRead *storageRead)
{
Assert(storageRead != NULL);
Assert(storageRead->isActive);
return storageRead->segmentFileName;
}
/*
* Finish using the AppendOnlyStorageRead session created with ~Init.
*/
void
AppendOnlyStorageRead_FinishSession(AppendOnlyStorageRead *storageRead)
{
MemoryContext oldMemoryContext;
if (!storageRead->isActive)
return;
oldMemoryContext = MemoryContextSwitchTo(storageRead->memoryContext);
/*
* UNDONE: This expects the MemoryContext to be what was used for the
* 'memory' in ~Init
*/
BufferedReadFinish(&storageRead->bufferedRead);
if (storageRead->relationName != NULL)
{
pfree(storageRead->relationName);
storageRead->relationName = NULL;
}
if (storageRead->segmentFileName != NULL)
{
pfree(storageRead->segmentFileName);
storageRead->segmentFileName = NULL;
}
if (storageRead->compression_functions != NULL)
{
callCompressionDestructor(storageRead->compression_functions[COMPRESSION_DESTRUCTOR], storageRead->compressionState);
if (storageRead->compressionState != NULL)
{
pfree(storageRead->compressionState);
storageRead->compressionState = NULL;
}
pfree(storageRead->compression_functions);
storageRead->compression_functions = NULL;
}
/* Deallocation is done. Go back to caller memory-context. */
MemoryContextSwitchTo(oldMemoryContext);
storageRead->isActive = false;
}
/*----------------------------------------------------------------
* Open and Close
*----------------------------------------------------------------
*/
/*
* Do open the next segment file to read, but don't do error processing.
*
* This routine is responsible for seeking to the proper location given
* the logical EOF.
*
* filePathName - name of the segment file to open.
*/
static File
AppendOnlyStorageRead_DoOpenFile(AppendOnlyStorageRead *storageRead,
char *filePathName)
{
int fileFlags = O_RDONLY | PG_BINARY;
File file;
Assert(storageRead != NULL);
Assert(storageRead->isActive);
Assert(filePathName != NULL);
elogif(Debug_appendonly_print_read_block, LOG,
"Append-Only storage read: opening table '%s', segment file '%s', fileFlags 0x%x",
storageRead->relationName,
filePathName,
fileFlags);
/*
* Open the file for read.
*/
file = PathNameOpenFile(filePathName, fileFlags);
return file;
}
/*
* Finish the open by positioning the next read and saving information.
*
* file - The open file.
* filePathName - name of the segment file to open.
* version - AO table format version the file is in.
* logicalEof - snapshot version of the EOF value to use as the read end
* of the segment file.
*/
static void
AppendOnlyStorageRead_FinishOpenFile(AppendOnlyStorageRead *storageRead,
File file,
char *filePathName,
int version,
int64 logicalEof)
{
MemoryContext oldMemoryContext;
AORelationVersion_CheckValid(version);
storageRead->file = file;
storageRead->formatVersion = version;
/*
* When reading multiple segment files, we throw away the old segment file
* name strings.
*/
oldMemoryContext = MemoryContextSwitchTo(storageRead->memoryContext);
if (storageRead->segmentFileName != NULL)
pfree(storageRead->segmentFileName);
storageRead->segmentFileName = pstrdup(filePathName);
/* Allocation is done. Go back to caller memory-context. */
MemoryContextSwitchTo(oldMemoryContext);
storageRead->logicalEof = logicalEof;
BufferedReadSetFile(&storageRead->bufferedRead,
storageRead->file,
storageRead->segmentFileName,
logicalEof);
}
/*
* Open the next segment file to read.
*
* This routine is responsible for seeking to the proper
* read location given the logical EOF.
*
* filePathName - name of the segment file to open.
* version - AO table format version the file is in.
* logicalEof - snapshot version of the EOF value to use as the read end
* of the segment file.
*/
void
AppendOnlyStorageRead_OpenFile(AppendOnlyStorageRead *storageRead,
char *filePathName,
int version,
int64 logicalEof)
{
File file;
Assert(storageRead != NULL);
Assert(storageRead->isActive);
Assert(filePathName != NULL);
/*
* The EOF must be greater than 0, otherwise we risk transactionally
* created segment files from disappearing if a concurrent write
* transaction aborts.
*/
if (logicalEof == 0)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("append-only storage read segment file '%s' EOF must be > 0 for relation '%s'",
filePathName,
storageRead->relationName)));
file = AppendOnlyStorageRead_DoOpenFile(storageRead,
filePathName);
if (file < 0)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("append-Only storage read could not open segment file '%s' for relation '%s'",
filePathName,
storageRead->relationName)));
}
AppendOnlyStorageRead_FinishOpenFile(storageRead,
file,
filePathName,
version,
logicalEof);
}
/*
* Try opening the next segment file to read.
*
* This routine is responsible for seeking to the proper read location given
* the logical EOF.
*
* filePathName - name of the segment file to open
* version - AO table format version the file is in.
* logicalEof - snapshot version of the EOF value to use as the read end of
* the segment file.
*/
bool
AppendOnlyStorageRead_TryOpenFile(AppendOnlyStorageRead *storageRead,
char *filePathName,
int version,
int64 logicalEof)
{
File file;
Assert(storageRead != NULL);
Assert(storageRead->isActive);
Assert(filePathName != NULL);
/* UNDONE: Range check logicalEof */
file = AppendOnlyStorageRead_DoOpenFile(storageRead,
filePathName);
if (file < 0)
return false;
AppendOnlyStorageRead_FinishOpenFile(storageRead,
file,
filePathName,
version,
logicalEof);
return true;
}
/*
* Set a temporary read range in the current open segment file.
*
* The beginFileOffset must be to the beginning of an Append-Only Storage block.
*
* The afterFileOffset serves as the temporary EOF. It will cause
* ~_GetBlockInfo to return false (no more blocks) when reached. It must be
* at the end of an Append-Only Storage block.
*
* When ~_GetBlockInfo returns false (no more blocks), the temporary read
* range is forgotten.
*/
void
AppendOnlyStorageRead_SetTemporaryRange(AppendOnlyStorageRead *storageRead,
int64 beginFileOffset,
int64 afterFileOffset)
{
Assert(storageRead->isActive);
Assert(storageRead->file != -1);
Assert(storageRead->formatVersion != -1);
Assert(beginFileOffset >= 0);
Assert(beginFileOffset <= storageRead->logicalEof);
Assert(afterFileOffset >= 0);
Assert(afterFileOffset <= storageRead->logicalEof);
BufferedReadSetTemporaryRange(&storageRead->bufferedRead,
beginFileOffset,
afterFileOffset);
}
/*
* Close the current segment file.
*
* No error if the current is already closed.
*/
void
AppendOnlyStorageRead_CloseFile(AppendOnlyStorageRead *storageRead)
{
if (!storageRead->isActive)
return;
if (storageRead->file == -1)
return;
FileClose(storageRead->file);
storageRead->file = -1;
storageRead->formatVersion = -1;
storageRead->logicalEof = INT64CONST(0);
if (storageRead->bufferedRead.file >= 0)
BufferedReadCompleteFile(&storageRead->bufferedRead);
}
/*----------------------------------------------------------------
* Reading Content
*----------------------------------------------------------------
*/
/*
* This section describes for reading potentially long content that can be
* up to 1 Gb long and and/or content may have been be bulk-compressed.
*
* The AppendOnlyStorageRead_GetBlockInfo routine is used to peek at the
* next Append-Only Storage Block and tell the caller how to handle it.
*
* If the block is small and not compressed, then it may be looked at
* directly in the read buffer.
*
* Otherwise, the caller must provide other buffer space to either
* reconstruct large content and/or to decompress content into.
*/
/*
* Skip zero padding to next page boundary, if necessary.
*
* This function is called when the file system block we are scanning has
* no more valid data but instead is padded with zero's from the position
* we are currently in until the end of the block. The function will skip
* to the end of block if skipLen is -1 or skip skipLen bytes otherwise.
*/
static void
AppendOnlyStorageRead_DoSkipPadding(AppendOnlyStorageRead *storageRead,
int32 skipLen)
{
int64 nextReadPosition;
int64 nextBoundaryPosition;
int32 safeWriteRemainder;
bool doSkip;
uint8 *buffer;
int32 availableLen;
int32 safewrite = storageRead->storageAttributes.safeFSWriteSize;
/* early exit if no pad used */
if (safewrite == 0)
return;
nextReadPosition =
BufferedReadNextBufferPosition(&storageRead->bufferedRead);
nextBoundaryPosition =
((nextReadPosition + safewrite - 1) / safewrite) * safewrite;
safeWriteRemainder = (int32) (nextBoundaryPosition - nextReadPosition);
if (safeWriteRemainder <= 0)
doSkip = false;
else if (skipLen == -1)
{
/*
* Skip to end of page.
*/
doSkip = true;
}
else
doSkip = (safeWriteRemainder < skipLen);
if (doSkip)
{
/*
* Read through the remainder.
*/
buffer = BufferedReadGetNextBuffer(&storageRead->bufferedRead,
safeWriteRemainder,
&availableLen);
/*
* Since our file EOF should always be a multiple of the file-system
* page, we do not expect a short read here.
*/
if (buffer == NULL)
availableLen = 0;
if (buffer == NULL || safeWriteRemainder != availableLen)
{
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("unexpected end of file"),
errdetail("Expected to read %d bytes after position " INT64_FORMAT " but found %d bytes (bufferCount " INT64_FORMAT ").",
safeWriteRemainder,
nextReadPosition,
availableLen,
storageRead->bufferCount)));
}
/*
* UNDONE: For verification purposes, we should verify the remainder
* is all zeroes.
*/
elogif(Debug_appendonly_print_scan, LOG,
"Append-only scan skipping zero padded remainder for table '%s' (nextReadPosition = " INT64_FORMAT ", safeWriteRemainder = %d)",
storageRead->relationName,
nextReadPosition,
safeWriteRemainder);
}
}
/*
* Skip zero padding to next page boundary, if necessary.
*
* This function is called when the file system block we are scanning has
* no more valid data but instead is padded with zero's from the position
* we are currently in until the end of the block. The function will skip
* to the end of block if skipLen is -1 or skip skipLen bytes otherwise.
*/
static bool
AppendOnlyStorageRead_PositionToNextBlock(AppendOnlyStorageRead *storageRead,
int64 *headerOffsetInFile,
uint8 **header,
int32 *blockLimitLen)
{
int32 availableLen;
int i;
int64 fileRemainderLen;
Assert(storageRead != NULL);
Assert(header != NULL);
/*
* Peek ahead just enough so we can see the Append-Only storage header.
*
* However, we need to honor the file-system page boundaries here since we
* do not let the length information cross the boundary.
*/
AppendOnlyStorageRead_DoSkipPadding(storageRead, storageRead->minimumHeaderLen);
*headerOffsetInFile =
BufferedReadNextBufferPosition(&storageRead->bufferedRead);
*header = BufferedReadGetNextBuffer(&storageRead->bufferedRead,
storageRead->minimumHeaderLen,
&availableLen);
if (*header == NULL)
{
/* done reading the file */
return false;
}
storageRead->bufferCount++;
if (availableLen != storageRead->minimumHeaderLen)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("expected %d bytes and got %d bytes in table %s (segment file '%s', header offset in file = " INT64_FORMAT ", bufferCount " INT64_FORMAT ")",
storageRead->minimumHeaderLen,
availableLen,
storageRead->relationName,
storageRead->segmentFileName,
*headerOffsetInFile,
storageRead->bufferCount)));
/*
* First check for zero padded page remainder.
*/
i = 0;
while (true)
{
if ((*header)[i] != 0)
break;
i++;
if (i >= storageRead->minimumHeaderLen)
{
/*
* Skip over zero padding caused when the append command left a
* partially full page.
*/
AppendOnlyStorageRead_DoSkipPadding(storageRead,
-1 /* means till end of page */ );
/*
* Now try to get the peek data from the new page.
*/
*headerOffsetInFile = BufferedReadNextBufferPosition(&storageRead->bufferedRead);
*header = BufferedReadGetNextBuffer(&storageRead->bufferedRead,
storageRead->minimumHeaderLen,
&availableLen);
if (*header == NULL)
{
/* done reading the file */
return false;
}
if (availableLen != storageRead->minimumHeaderLen)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("expected %d bytes and found %d bytes in table %s (segment file '%s', header offset in file = " INT64_FORMAT ", bufferCount " INT64_FORMAT ")",
storageRead->minimumHeaderLen,
availableLen,
storageRead->relationName,
storageRead->segmentFileName,
*headerOffsetInFile,
storageRead->bufferCount)));
break;
}
}
/*
* Determine the maximum boundary of the block. UNDONE: When we have a
* block directory, we will tighten the limit down.
*/
fileRemainderLen = storageRead->bufferedRead.fileLen -
*headerOffsetInFile;
if (storageRead->maxBufferLen > fileRemainderLen)
*blockLimitLen = (int32) fileRemainderLen;
else
*blockLimitLen = storageRead->maxBufferLen;
return true;
}
char *
AppendOnlyStorageRead_ContextStr(AppendOnlyStorageRead *storageRead)
{
int64 headerOffsetInFile;
headerOffsetInFile =
BufferedReadCurrentPosition(&storageRead->bufferedRead);
return psprintf("%s. Append-Only segment file '%s', block header offset in file = " INT64_FORMAT ", bufferCount " INT64_FORMAT,
storageRead->title,
storageRead->segmentFileName,
headerOffsetInFile,
storageRead->bufferCount);
}
/*
* errcontext_appendonly_read_storage_block
*
* Add an errcontext() line showing the table, segment file, offset in file,
* block count of the storage block being read.
*/
int
errcontext_appendonly_read_storage_block(AppendOnlyStorageRead *storageRead)
{
char *str;
str = AppendOnlyStorageRead_ContextStr(storageRead);
errcontext("%s", str);
pfree(str);
return 0;
}
char *
AppendOnlyStorageRead_StorageContentHeaderStr(AppendOnlyStorageRead *storageRead)
{
uint8 *header;
header = BufferedReadGetCurrentBuffer(&storageRead->bufferedRead);
return AppendOnlyStorageFormat_BlockHeaderStr(header,
storageRead->storageAttributes.checksum,
storageRead->formatVersion);
}
/*
* errdetail_appendonly_read_storage_content_header
*
* Add an errdetail() line showing the Append-Only Storage header being read.
*/
int
errdetail_appendonly_read_storage_content_header(AppendOnlyStorageRead *storageRead)
{
char *str;
str = AppendOnlyStorageRead_StorageContentHeaderStr(storageRead);
errdetail("%s", str);
pfree(str);
return 0;
}
static void
AppendOnlyStorageRead_LogBlockHeader(AppendOnlyStorageRead *storageRead,
uint8 *header)
{
char *contextStr;
char *blockHeaderStr;
contextStr = AppendOnlyStorageRead_ContextStr(storageRead);
blockHeaderStr =
AppendOnlyStorageFormat_SmallContentHeaderStr(header,
storageRead->storageAttributes.checksum,
storageRead->formatVersion);
ereport(LOG,
(errmsg("%s. %s",
contextStr,
blockHeaderStr)));
pfree(contextStr);
pfree(blockHeaderStr);
}
/*
* Get information on the next Append-Only Storage Block.
*
* Return true if another block was found. Otherwise, we have reached the
* end of the current segment file.
*/
bool
AppendOnlyStorageRead_ReadNextBlock(AppendOnlyStorageRead *storageRead)
{
uint8 *header;
AOHeaderCheckError checkError;
int32 blockLimitLen = 0; /* Shutup compiler. */
pg_crc32 storedChecksum;
pg_crc32 computedChecksum;
/*
* Reset current* variables.
*/
/* For efficiency, zero out. Comment out lines that set fields to 0. */
memset(&storageRead->current, 0, sizeof(AppendOnlyStorageReadCurrent));
/* storageRead->current.headerOffsetInFile = 0; */
storageRead->current.headerKind = AoHeaderKind_None;
/* storageRead->current.actualHeaderLen = 0; */
/* storageRead->current.contentLen = 0; */
/* storageRead->current.overallBlockLen = 0; */
/* storageRead->current.contentOffset = 0; */
/* storageRead->current.executorBlockKind = 0; */
/* storageRead->current.hasFirstRowNum = false; */
storageRead->current.firstRowNum = INT64CONST(-1);
/* storageRead->current.rowCount = 0; */
/* storageRead->current.isLarge = false; */
/* storageRead->current.isCompressed = false; */
/* storageRead->current.compressedLen = 0; */
elogif(Debug_appendonly_print_datumstream, LOG,
"before AppendOnlyStorageRead_PositionToNextBlock, storageRead->current.headerOffsetInFile is" INT64_FORMAT "storageRead->current.overallBlockLen is %d",
storageRead->current.headerOffsetInFile, storageRead->current.overallBlockLen);
if (!AppendOnlyStorageRead_PositionToNextBlock(storageRead,
&storageRead->current.headerOffsetInFile,
&header,
&blockLimitLen))
{
/* Done reading the file */
return false;
}
elogif(Debug_appendonly_print_datumstream, LOG,
"after AppendOnlyStorageRead_PositionToNextBlock, storageRead->current.headerOffsetInFile is" INT64_FORMAT "storageRead->current.overallBlockLen is %d",
storageRead->current.headerOffsetInFile, storageRead->current.overallBlockLen);
/*----------
* Proceed very carefully:
* [ 1. Verify header checksum ]
* 2. Examine (basic) header.
* 3. Examine specific header.
* [ 4. Verify the block checksum ]
*----------
*/
if (storageRead->storageAttributes.checksum &&
gp_appendonly_verify_block_checksums)
{
if (!AppendOnlyStorageFormat_VerifyHeaderChecksum(header,
&storedChecksum,
&computedChecksum))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("header checksum does not match, expected 0x%08X and found 0x%08X",
storedChecksum, computedChecksum),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
}
/*
* Check the (basic) header information.
*/
checkError = AppendOnlyStorageFormat_GetHeaderInfo(header,
storageRead->storageAttributes.checksum,
&storageRead->current.headerKind,
&storageRead->current.actualHeaderLen);
if (checkError != AOHeaderCheckOk)
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("bad append-only storage header, header check error %d, detail '%s'",
(int) checkError,
AppendOnlyStorageFormat_GetHeaderCheckErrorStr()),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
/*
* Get more header since AppendOnlyStorageRead_PositionToNextBlock only
* gets minimum.
*/
if (storageRead->minimumHeaderLen < storageRead->current.actualHeaderLen)
{
int32 availableLen;
header = BufferedReadGrowBuffer(&storageRead->bufferedRead,
storageRead->current.actualHeaderLen,
&availableLen);
if (header == NULL ||
availableLen != storageRead->current.actualHeaderLen)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("expected %d bytes and found %d bytes in table %s (segment file '%s', header offset in file = " INT64_FORMAT ", bufferCount " INT64_FORMAT ")",
storageRead->current.actualHeaderLen,
availableLen,
storageRead->relationName,
storageRead->segmentFileName,
storageRead->current.headerOffsetInFile,
storageRead->bufferCount)));
}
/*
* Based on the kind of header, we either have small or large content.
*/
switch (storageRead->current.headerKind)
{
case AoHeaderKind_SmallContent:
/*
* Check the SmallContent header information.
*/
checkError = AppendOnlyStorageFormat_GetSmallContentHeaderInfo
(header,
storageRead->current.actualHeaderLen,
storageRead->storageAttributes.checksum,
blockLimitLen,
&storageRead->current.overallBlockLen,
&storageRead->current.contentOffset,
&storageRead->current.uncompressedLen,
&storageRead->current.executorBlockKind,
&storageRead->current.hasFirstRowNum,
storageRead->formatVersion,
&storageRead->current.firstRowNum,
&storageRead->current.rowCount,
&storageRead->current.isCompressed,
&storageRead->current.compressedLen
);
if (checkError != AOHeaderCheckOk)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("bad append-only storage header of type small content, header check error %d, detail '%s'",
(int) checkError,
AppendOnlyStorageFormat_GetHeaderCheckErrorStr()),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
break;
case AoHeaderKind_LargeContent:
/*
* Check the LargeContent metadata header information.
*/
checkError = AppendOnlyStorageFormat_GetLargeContentHeaderInfo
(header,
storageRead->current.actualHeaderLen,
storageRead->storageAttributes.checksum,
&storageRead->current.uncompressedLen,
&storageRead->current.executorBlockKind,
&storageRead->current.hasFirstRowNum,
&storageRead->current.firstRowNum,
&storageRead->current.rowCount);
if (checkError != AOHeaderCheckOk)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("bad append-only storage header of type large content, header check error %d, detail '%s'",
(int) checkError,
AppendOnlyStorageFormat_GetHeaderCheckErrorStr()),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
storageRead->current.isLarge = true;
break;
case AoHeaderKind_NonBulkDenseContent:
/*
* Check the NonBulkDense header information.
*/
checkError =
AppendOnlyStorageFormat_GetNonBulkDenseContentHeaderInfo
(header,
storageRead->current.actualHeaderLen,
storageRead->storageAttributes.checksum,
blockLimitLen,
&storageRead->current.overallBlockLen,
&storageRead->current.contentOffset,
&storageRead->current.uncompressedLen,
&storageRead->current.executorBlockKind,
&storageRead->current.hasFirstRowNum,
storageRead->formatVersion,
&storageRead->current.firstRowNum,
&storageRead->current.rowCount
);
if (checkError != AOHeaderCheckOk)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("bad append-only storage header of type non-bulk dense content, header check error %d, detail '%s'",
(int) checkError,
AppendOnlyStorageFormat_GetHeaderCheckErrorStr()),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
break;
case AoHeaderKind_BulkDenseContent:
/*
* Check the BulkDenseContent header information.
*/
checkError =
AppendOnlyStorageFormat_GetBulkDenseContentHeaderInfo
(header,
storageRead->current.actualHeaderLen,
storageRead->storageAttributes.checksum,
blockLimitLen,
&storageRead->current.overallBlockLen,
&storageRead->current.contentOffset,
&storageRead->current.uncompressedLen,
&storageRead->current.executorBlockKind,
&storageRead->current.hasFirstRowNum,
storageRead->formatVersion,
&storageRead->current.firstRowNum,
&storageRead->current.rowCount,
&storageRead->current.isCompressed,
&storageRead->current.compressedLen
);
if (checkError != AOHeaderCheckOk)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("bad append-only storage header of type bulk dense content, header check error %d, detail '%s'",
(int) checkError,
AppendOnlyStorageFormat_GetHeaderCheckErrorStr()),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
break;
default:
elog(ERROR, "unexpected append-only header kind %d",
storageRead->current.headerKind);
break;
}
if (Debug_appendonly_print_storage_headers)
{
AppendOnlyStorageRead_LogBlockHeader(storageRead, header);
}
if (storageRead->current.hasFirstRowNum)
{
/* UNDONE: Grow buffer and read the value into firstRowNum. */
}
if (storageRead->current.headerKind == AoHeaderKind_LargeContent)
{
/* UNDONE: Finish the read for the information only header. */
}
return true;
}
/*
* Get information on the next Append-Only Storage Block.
*
* Return true if another block was found. Otherwise, when we have reached
* the end of the current segment file.
*
* OUTPUTS:
*
* contentLen - total byte length of the content.
* executorBlockKind - executor supplied value stored in the Append-Only
* Storage Block header
* firstRowNum - When the first row number for this block was explicitly set,
* that value is returned here. Otherwise, INT64CONST(-1) is
* returned.
* rowCount - number of rows in the content
* isLarge - When true, the content was longer than the maxBufferLen
* (i.e. blocksize) minus Append-Only Storage Block header and
* had to be stored in more than one storage block.
* isCompressed - When true, the content is compressed and cannot be looked at
* directly in the buffer.
*/
bool
AppendOnlyStorageRead_GetBlockInfo(AppendOnlyStorageRead *storageRead,
int32 *contentLen,
int *executorBlockKind,
int64 *firstRowNum,
int *rowCount,
bool *isLarge,
bool *isCompressed)
{
bool isNext;
Assert(storageRead != NULL);
Assert(storageRead->isActive);
isNext = AppendOnlyStorageRead_ReadNextBlock(storageRead);
/*
* The current* variables have good values even when there is no next
* block.
*/
*contentLen = storageRead->current.uncompressedLen;
*executorBlockKind = storageRead->current.executorBlockKind;
*firstRowNum = storageRead->current.firstRowNum;
*rowCount = storageRead->current.rowCount;
*isLarge = storageRead->current.isLarge;
*isCompressed = storageRead->current.isCompressed;
return isNext;
}
/*
* Return the file offset of the current Append-Only Storage Block.
*/
int64
AppendOnlyStorageRead_CurrentHeaderOffsetInFile(AppendOnlyStorageRead *storageRead)
{
Assert(storageRead != NULL);
Assert(storageRead->isActive);
return storageRead->current.headerOffsetInFile;
}
/*
* Return the compressed length of the content of the current Append-Only
* Storage Block.
*/
int64
AppendOnlyStorageRead_CurrentCompressedLen(AppendOnlyStorageRead *storageRead)
{
Assert(storageRead != NULL);
Assert(storageRead->isActive);
return storageRead->current.compressedLen;
}
/*
* Return the overall block length of the current Append-Only Storage Block.
*/
int64
AppendOnlyStorageRead_OverallBlockLen(AppendOnlyStorageRead *storageRead)
{
Assert(storageRead != NULL);
Assert(storageRead->isActive);
return storageRead->current.overallBlockLen;
}
/*
* Internal routine to grow the BufferedRead buffer to be the whole current
* block and to get header and content pointers of current block.
*
* Since we are growing the BufferedRead buffer to the whole block, old
* pointers to the header must be abandoned.
*
* Header to current block was read and verified by
* AppendOnlyStorageRead_ReadNextBlock.
*/
static void
AppendOnlyStorageRead_InternalGetBuffer(AppendOnlyStorageRead *storageRead,
uint8 **header, uint8 **content)
{
int32 availableLen;
pg_crc32 storedChecksum;
pg_crc32 computedChecksum;
/*
* Verify next block is type Block.
*/
Assert(storageRead->current.headerKind == AoHeaderKind_SmallContent ||
storageRead->current.headerKind == AoHeaderKind_NonBulkDenseContent ||
storageRead->current.headerKind == AoHeaderKind_BulkDenseContent);
/*
* Grow the buffer to the full block length to avoid any unnecessary
* copying by BufferedRead.
*
* Since the BufferedRead module may have to copy information around, we
* do not save any pointers to the prior buffer call. This why
* AppendOnlyStorageFormat_GetHeaderInfo passes back the offset to the
* data, not a pointer.
*/
*header = BufferedReadGrowBuffer(&storageRead->bufferedRead,
storageRead->current.overallBlockLen,
&availableLen);
if (storageRead->current.overallBlockLen != availableLen)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("wrong buffer length, expected %d byte length buffer and got %d",
storageRead->current.overallBlockLen,
availableLen),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
if (storageRead->storageAttributes.checksum &&
gp_appendonly_verify_block_checksums)
{
/*
* Now that the header has been verified, verify the block checksum in
* the header with the checksum of the data portion.
*/
if (!AppendOnlyStorageFormat_VerifyBlockChecksum(*header,
storageRead->current.overallBlockLen,
&storedChecksum,
&computedChecksum))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("block checksum does not match, expected 0x%08X and found 0x%08X",
storedChecksum,
computedChecksum),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
}
*content = &((*header)[storageRead->current.contentOffset]);
}
/*
* Get a pointer to the *small* non-compressed content.
*
* This interface provides a pointer directly into the read buffer for
* efficient data use.
*/
uint8 *
AppendOnlyStorageRead_GetBuffer(AppendOnlyStorageRead *storageRead)
{
uint8 *header;
uint8 *content;
Assert(storageRead != NULL);
Assert(storageRead->isActive);
/*
* Verify next block is a "small" non-compressed block.
*/
Assert(storageRead->current.headerKind == AoHeaderKind_SmallContent ||
storageRead->current.headerKind == AoHeaderKind_NonBulkDenseContent ||
storageRead->current.headerKind == AoHeaderKind_BulkDenseContent);
Assert(!storageRead->current.isLarge);
Assert(!storageRead->current.isCompressed);
/*
* Fetch pointers to content.
*/
AppendOnlyStorageRead_InternalGetBuffer(storageRead,
&header,
&content);
return content;
}
/*
* Copy the large and/or decompressed content out.
*
* The contentOutLen parameter value must match the contentLen from the
* AppendOnlyStorageReadGetBlockInfo call.
*
* Note this routine will work for small non-compressed content, too.
*
* contentOut - memory to receive the contiguous content.
* contentOutLen - byte length of the contentOut buffer.
*/
void
AppendOnlyStorageRead_Content(AppendOnlyStorageRead *storageRead,
uint8 *contentOut,
int32 contentOutLen)
{
Assert(storageRead != NULL);
Assert(storageRead->isActive);
Assert(contentOutLen == storageRead->current.uncompressedLen);
if (storageRead->current.isLarge)
{
int64 largeContentPosition; /* Position of the large content
* metadata block. */
int32 largeContentLen; /* Total length of the large content. */
int32 remainingLargeContentLen; /* The remaining number of
* bytes to read for the large
* content. */
uint8 *contentNext; /* Pointer inside the contentOut buffer to
* put the next byte. */
int32 regularBlockReadCount; /* Number of regular blocks read
* after the metadata block. */
int32 regularContentLen; /* Length of the current regular
* block's content. */
/*
* Large content.
*
* We have the LargeContent "metadata" AO block with the total length
* (already read) followed by N SmallContent blocks with the fragments
* of the large content.
*/
/*
* Save any values needed from the current* members since they will be
* modifed as we read the regular blocks.
*/
largeContentPosition = storageRead->current.headerOffsetInFile;
largeContentLen = storageRead->current.uncompressedLen;
/*
* Loop to read regular blocks.
*/
contentNext = contentOut;
remainingLargeContentLen = largeContentLen;
regularBlockReadCount = 0;
while (true)
{
/*
* Read next regular block.
*/
regularBlockReadCount++;
if (!AppendOnlyStorageRead_ReadNextBlock(storageRead))
{
/*
* Unexpected end of file.
*/
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("unexpected end of file trying to read block %d of large content in segment file '%s' of table '%s'",
regularBlockReadCount,
storageRead->segmentFileName,
storageRead->relationName),
errdetail("Large content metadata block is at position " INT64_FORMAT " Large content length %d",
largeContentPosition,
largeContentLen)));
}
if (storageRead->current.headerKind != AoHeaderKind_SmallContent)
{
/*
* Unexpected headerKind.
*/
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("expected header kind 'Block' for block %d of large content in segment file '%s' of table '%s'",
regularBlockReadCount,
storageRead->segmentFileName,
storageRead->relationName),
errdetail("Large content metadata block is at position " INT64_FORMAT " Large content length %d",
largeContentPosition,
largeContentLen)));
}
Assert(!storageRead->current.isLarge);
regularContentLen = storageRead->current.uncompressedLen;
remainingLargeContentLen -= regularContentLen;
if (remainingLargeContentLen < 0)
{
/*
* Too much data found???
*/
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("too much data found after reading %d blocks for large content in segment file '%s' of table '%s'",
regularBlockReadCount,
storageRead->segmentFileName,
storageRead->relationName),
errdetail("Large content metadata block is at position " INT64_FORMAT " Large content length %d; extra data length %d",
largeContentPosition,
largeContentLen,
-remainingLargeContentLen)));
}
/*
* We can safely recurse one level here.
*/
AppendOnlyStorageRead_Content(storageRead,
contentNext,
regularContentLen);
if (remainingLargeContentLen == 0)
break;
/*
* Advance our pointer inside the contentOut buffer to put the
* next bytes.
*/
contentNext += regularContentLen;
}
}
else
{
uint8 *header;
uint8 *content;
/*
* "Small" content in one regular block.
*/
/*
* Fetch pointers to content.
*/
AppendOnlyStorageRead_InternalGetBuffer(storageRead,
&header,
&content);
if (!storageRead->current.isCompressed)
{
/*
* Not compressed.
*/
memcpy(contentOut,
content,
storageRead->current.uncompressedLen);
if (Debug_appendonly_print_scan)
elog(LOG,
"Append-only Storage Read non-compressed block for table '%s' "
"(length = %d, segment file '%s', header offset in file = "
INT64_FORMAT ", block count " INT64_FORMAT ")",
storageRead->relationName,
storageRead->current.uncompressedLen,
storageRead->segmentFileName,
storageRead->current.headerOffsetInFile,
storageRead->bufferCount);
}
else
{
/*
* Compressed.
*/
PGFunction decompressor;
PGFunction *cfns = storageRead->compression_functions;
if (cfns == NULL)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("decompression information missing")));
decompressor = cfns[COMPRESSION_DECOMPRESS];
gp_decompress(content, /* Compressed data in block. */
storageRead->current.compressedLen,
contentOut,
storageRead->current.uncompressedLen,
decompressor,
storageRead->compressionState,
storageRead->bufferCount);
if (Debug_appendonly_print_scan)
elog(LOG,
"Append-only Storage Read decompressed block for table '%s' "
"(compressed length %d, uncompressed length = %d, segment file '%s', "
"header offset in file = " INT64_FORMAT ", block count " INT64_FORMAT ")",
storageRead->relationName,
AppendOnlyStorageFormat_GetCompressedLen(header),
storageRead->current.uncompressedLen,
storageRead->segmentFileName,
storageRead->current.headerOffsetInFile,
storageRead->bufferCount);
}
}
}
/*
* Skip the current block found with ~_GetBlockInfo.
*
* Do not decompress the block contents.
*
* Call this routine instead of calling ~_GetBuffer or ~_Contents that look at
* contents. Useful when the desired row(s) are not within the row range of
* the current block.
*/
void
AppendOnlyStorageRead_SkipCurrentBlock(AppendOnlyStorageRead *storageRead)
{
Assert(storageRead != NULL);
Assert(storageRead->isActive);
if (storageRead->current.isLarge)
{
int64 largeContentPosition; /* Position of the large content
* metadata block. */
int32 largeContentLen; /* Total length of the large content. */
int32 remainingLargeContentLen; /* Remaining number of bytes
* to read for the large
* content. */
int32 regularBlockReadCount; /* Number of regular blocks read
* after the metadata block. */
int32 regularContentLen; /* Length of the current regular
* block's content. */
int32 availableLen;
/*
* Large content.
*
* We have the LargeContent "metadata" AO block with the total length
* (already read) followed by N SmallContent blocks with the fragments
* of the large content.
*/
/*
* Save any values needed from the current* members since they will be
* modifed as we read the regular blocks.
*/
largeContentPosition = storageRead->current.headerOffsetInFile;
largeContentLen = storageRead->current.uncompressedLen;
/*
* Loop to read regular blocks.
*/
remainingLargeContentLen = largeContentLen;
regularBlockReadCount = 0;
while (true)
{
/*
* Read next regular block.
*/
regularBlockReadCount++;
if (!AppendOnlyStorageRead_ReadNextBlock(storageRead))
{
/*
* Unexpected end of file.
*/
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("unexpected end of file trying to read block %d of large content in segment file '%s' of table '%s'",
regularBlockReadCount,
storageRead->segmentFileName,
storageRead->relationName),
errdetail("Large content metadata block is at position " INT64_FORMAT " Large content length %d",
largeContentPosition, largeContentLen)));
}
if (storageRead->current.headerKind != AoHeaderKind_SmallContent)
{
/*
* Unexpected headerKind.
*/
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("expected header kind 'Block' for block %d of large content in segment file '%s' of table '%s'",
regularBlockReadCount,
storageRead->segmentFileName,
storageRead->relationName),
errdetail("Large content metadata block is at position " INT64_FORMAT " Large content length %d",
largeContentPosition, largeContentLen)));
}
Assert(!storageRead->current.isLarge);
BufferedReadGrowBuffer(&storageRead->bufferedRead,
storageRead->current.overallBlockLen,
&availableLen);
if (storageRead->current.overallBlockLen != availableLen)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("wrong buffer length, expected %d byte length buffer and got %d",
storageRead->current.overallBlockLen,
availableLen),
errdetail_appendonly_read_storage_content_header(storageRead),
errcontext_appendonly_read_storage_block(storageRead)));
regularContentLen = storageRead->current.uncompressedLen;
remainingLargeContentLen -= regularContentLen;
if (remainingLargeContentLen < 0)
{
/*
* Too much data found???
*/
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("too much data found after reading %d blocks for large content in segment file '%s' of table '%s'",
regularBlockReadCount,
storageRead->segmentFileName,
storageRead->relationName),
errdetail("Large content metadata block is at position " INT64_FORMAT " Large content length %d; extra data length %d",
largeContentPosition,
largeContentLen,
-remainingLargeContentLen)));
}
/*
* Since we are skipping, we do not use the compressed or
* uncompressed content.
*/
if (remainingLargeContentLen == 0)
break;
}
}
else
{
uint8 *header;
uint8 *content;
/*
* "Small" content in one regular block.
*/
/*
* Fetch pointers to content.
*
* Since we are skipping, we do not look at the content.
*/
AppendOnlyStorageRead_InternalGetBuffer(storageRead,
&header,
&content);
}
}
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