diff options
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/access/xlogreader.h | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h index 36907d6330c..3829ce2ab19 100644 --- a/src/include/access/xlogreader.h +++ b/src/include/access/xlogreader.h @@ -27,6 +27,7 @@ typedef struct XLogReaderState XLogReaderState; typedef int (*XLogPageReadCB) (XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, + XLogRecPtr targetRecPtr, char *readBuf, TimeLineID *pageTLI); @@ -46,11 +47,17 @@ struct XLogReaderState * -1 on failure. The callback shall sleep, if necessary, to wait for the * requested bytes to become available. The callback will not be invoked * again for the same page unless more than the returned number of bytes - * are necessary. + * are needed. * - * *pageTLI should be set to the TLI of the file the page was read from. - * It is currently used only for error reporting purposes, to reconstruct - * the name of the WAL file where an error occurred. + * targetRecPtr is the position of the WAL record we're reading. Usually + * it is equal to targetPagePtr + reqLen, but sometimes xlogreader needs + * to read and verify the page or segment header, before it reads the + * actual WAL record it's interested in. In that case, targetRecPtr can + * be used to determine which timeline to read the page from. + * + * The callback shall set *pageTLI to the TLI of the file the page was + * read from. It is currently used only for error reporting purposes, to + * reconstruct the name of the WAL file where an error occurred. */ XLogPageReadCB read_page; @@ -90,6 +97,9 @@ struct XLogReaderState XLogRecPtr latestPagePtr; TimeLineID latestPageTLI; + /* beginning of the WAL record being read. */ + XLogRecPtr currRecPtr; + /* Buffer for current ReadRecord result (expandable) */ char *readRecordBuf; uint32 readRecordBufSize; |