@ -71,7 +71,7 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...)
*/
XLogReaderState *
XLogReaderAllocate ( int wal_segment_size , const char * waldir ,
XLogPageReadCB pagereadfunc , void * private_data )
XLogReaderRoutine * routine , void * private_data )
{
XLogReaderState * state ;
@ -81,6 +81,9 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir,
if ( ! state )
return NULL ;
/* initialize caller-provided support functions */
state - > routine = * routine ;
state - > max_block_id = - 1 ;
/*
@ -102,7 +105,6 @@ XLogReaderAllocate(int wal_segment_size, const char *waldir,
WALOpenSegmentInit ( & state - > seg , & state - > segcxt , wal_segment_size ,
waldir ) ;
state - > read_page = pagereadfunc ;
/* system_identifier initialized to zeroes above */
state - > private_data = private_data ;
/* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */
@ -137,7 +139,7 @@ XLogReaderFree(XLogReaderState *state)
int block_id ;
if ( state - > seg . ws_file ! = - 1 )
close ( state - > seg . ws_fil e) ;
state - > routine . segment_close ( stat e) ;
for ( block_id = 0 ; block_id < = XLR_MAX_BLOCK_ID ; block_id + + )
{
@ -250,7 +252,7 @@ XLogBeginRead(XLogReaderState *state, XLogRecPtr RecPtr)
* XLogBeginRead ( ) or XLogFindNextRecord ( ) must be called before the first call
* to XLogReadRecord ( ) .
*
* If the read_ pagecallback fails to read the requested data , NULL is
* If the page_read callback fails to read the requested data , NULL is
* returned . The callback is expected to have reported the error ; errormsg
* is set to NULL .
*
@ -559,10 +561,10 @@ err:
/*
* Read a single xlog page including at least [ pageptr , reqLen ] of valid data
* via the read_ page( ) callback .
* via the page_read ( ) callback .
*
* Returns - 1 if the required page cannot be read for some reason ; errormsg_buf
* is set in that case ( unless the error occurs in the read_ pagecallback ) .
* is set in that case ( unless the error occurs in the page_read callback ) .
*
* We fetch the page from a reader - local cache if we know we have the required
* data and if there hasn ' t been any error since caching the data .
@ -589,7 +591,7 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
* Data is not in our buffer .
*
* Every time we actually read the segment , even if we looked at parts of
* it before , we need to do verification as the read_ pagecallback might
* it before , we need to do verification as the page_read callback might
* now be rereading data from a different source .
*
* Whenever switching to a new WAL segment , we read the first page of the
@ -601,9 +603,9 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
{
XLogRecPtr targetSegmentPtr = pageptr - targetPageOff ;
readLen = state - > read_page ( state , targetSegmentPtr , XLOG_BLCKSZ ,
state - > currRecPtr ,
state - > readBuf ) ;
readLen = state - > routine . page_read ( state , targetSegmentPtr , XLOG_BLCKSZ ,
state - > currRecPtr ,
state - > readBuf ) ;
if ( readLen < 0 )
goto err ;
@ -619,9 +621,9 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
* First , read the requested data length , but at least a short page header
* so that we can validate it .
*/
readLen = state - > read_page ( state , pageptr , Max ( reqLen , SizeOfXLogShortPHD ) ,
state - > currRecPtr ,
state - > readBuf ) ;
readLen = state - > routine . page_read ( state , pageptr , Max ( reqLen , SizeOfXLogShortPHD ) ,
state - > currRecPtr ,
state - > readBuf ) ;
if ( readLen < 0 )
goto err ;
@ -638,9 +640,9 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
/* still not enough */
if ( readLen < XLogPageHeaderSize ( hdr ) )
{
readLen = state - > read_page ( state , pageptr , XLogPageHeaderSize ( hdr ) ,
state - > currRecPtr ,
state - > readBuf ) ;
readLen = state - > routine . page_read ( state , pageptr , XLogPageHeaderSize ( hdr ) ,
state - > currRecPtr ,
state - > readBuf ) ;
if ( readLen < 0 )
goto err ;
}
@ -1041,11 +1043,14 @@ err:
# endif /* FRONTEND */
/*
* Helper function to ease writing of XLogRoutine - > page_read callbacks .
* If this function is used , caller must supply an open_segment callback in
* ' state ' , as that is used here .
*
* Read ' count ' bytes into ' buf ' , starting at location ' startptr ' , from WAL
* fetched from timeline ' tli ' .
*
* ' seg / segcxt ' identify the last segment used . ' openSegment ' is a callback
* to open the next segment , if necessary .
* ' seg / segcxt ' identify the last segment used .
*
* Returns true if succeeded , false if an error occurs , in which case
* ' errinfo ' receives error details .
@ -1054,9 +1059,10 @@ err:
* WAL buffers when possible .
*/
bool
WALRead ( char * buf , XLogRecPtr startptr , Size count , TimeLineID tli ,
WALRead ( XLogReaderState * state ,
char * buf , XLogRecPtr startptr , Size count , TimeLineID tli ,
WALOpenSegment * seg , WALSegmentContext * segcxt ,
WALSegmentOpen openSegment , WAL ReadError * errinfo )
WALReadError * errinfo )
{
char * p ;
XLogRecPtr recptr ;
@ -1086,10 +1092,11 @@ WALRead(char *buf, XLogRecPtr startptr, Size count, TimeLineID tli,
XLogSegNo nextSegNo ;
if ( seg - > ws_file > = 0 )
close ( seg - > ws_fil e) ;
state - > routine . segment_close ( stat e) ;
XLByteToSeg ( recptr , nextSegNo , segcxt - > ws_segsize ) ;
seg - > ws_file = openSegment ( nextSegNo , segcxt , & tli ) ;
seg - > ws_file = state - > routine . segment_open ( state , nextSegNo ,
segcxt , & tli ) ;
/* Update the current segment info. */
seg - > ws_tli = tli ;
Alvaro Herrera
5 years ago