diff options
Diffstat (limited to 'src/include/access/xlogreader.h')
| -rw-r--r-- | src/include/access/xlogreader.h | 77 |
1 files changed, 76 insertions, 1 deletions
diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index ea873a2d9c7..eb6cc8996a5 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -14,12 +14,18 @@ * * The basic idea is to allocate an XLogReaderState via * XLogReaderAllocate(), and call XLogReadRecord() until it returns NULL. + * + * After reading a record with XLogReadRecord(), it's decomposed into + * the per-block and main data parts, and the parts can be accessed + * with the XLogRec* macros and functions. You can also decode a + * record that's already constructed in memory, without reading from + * disk, by calling the DecodeXLogRecord() function. *------------------------------------------------------------------------- */ #ifndef XLOGREADER_H #define XLOGREADER_H -#include "access/xlog_internal.h" +#include "access/xlogrecord.h" typedef struct XLogReaderState XLogReaderState; @@ -31,6 +37,32 @@ typedef int (*XLogPageReadCB) (XLogReaderState *xlogreader, char *readBuf, TimeLineID *pageTLI); +typedef struct +{ + /* Is this block ref in use? */ + bool in_use; + + /* Identify the block this refers to */ + RelFileNode rnode; + ForkNumber forknum; + BlockNumber blkno; + + /* copy of the fork_flags field from the XLogRecordBlockHeader */ + uint8 flags; + + /* Information on full-page image, if any */ + bool has_image; + char *bkp_image; + uint16 hole_offset; + uint16 hole_length; + + /* Buffer holding the rmgr-specific data associated with this block */ + bool has_data; + char *data; + uint16 data_len; + uint16 data_bufsz; +} DecodedBkpBlock; + struct XLogReaderState { /* ---------------------------------------- @@ -79,6 +111,25 @@ struct XLogReaderState XLogRecPtr ReadRecPtr; /* start of last record read */ XLogRecPtr EndRecPtr; /* end+1 of last record read */ + + /* ---------------------------------------- + * Decoded representation of current record + * + * Use XLogRecGet* functions to investigate the record; these fields + * should not be accessed directly. + * ---------------------------------------- + */ + XLogRecord *decoded_record; /* currently decoded record */ + + char *main_data; /* record's main data portion */ + uint32 main_data_len; /* main data portion's length */ + uint32 main_data_bufsz; /* allocated size of the buffer */ + + /* information about blocks referenced by the record. */ + DecodedBkpBlock blocks[XLR_MAX_BLOCK_ID + 1]; + + int max_block_id; /* highest block_id in use (-1 if none) */ + /* ---------------------------------------- * private/internal state * ---------------------------------------- @@ -123,4 +174,28 @@ extern struct XLogRecord *XLogReadRecord(XLogReaderState *state, extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr); #endif /* FRONTEND */ +/* Functions for decoding an XLogRecord */ + +extern bool DecodeXLogRecord(XLogReaderState *state, XLogRecord *record, + char **errmsg); + +#define XLogRecGetTotalLen(decoder) ((decoder)->decoded_record->xl_tot_len) +#define XLogRecGetPrev(decoder) ((decoder)->decoded_record->xl_prev) +#define XLogRecGetInfo(decoder) ((decoder)->decoded_record->xl_info) +#define XLogRecGetRmid(decoder) ((decoder)->decoded_record->xl_rmid) +#define XLogRecGetXid(decoder) ((decoder)->decoded_record->xl_xid) +#define XLogRecGetData(decoder) ((decoder)->main_data) +#define XLogRecGetDataLen(decoder) ((decoder)->main_data_len) +#define XLogRecHasAnyBlockRefs(decoder) ((decoder)->max_block_id >= 0) +#define XLogRecHasBlockRef(decoder, block_id) \ + ((decoder)->blocks[block_id].in_use) +#define XLogRecHasBlockImage(decoder, block_id) \ + ((decoder)->blocks[block_id].has_image) + +extern bool RestoreBlockImage(XLogReaderState *recoder, uint8 block_id, char *dst); +extern char *XLogRecGetBlockData(XLogReaderState *record, uint8 block_id, Size *len); +extern bool XLogRecGetBlockTag(XLogReaderState *record, uint8 block_id, + RelFileNode *rnode, ForkNumber *forknum, + BlockNumber *blknum); + #endif /* XLOGREADER_H */ |