Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit3a4a353

Browse files
committed
Secondary refactor of heap scanning functions
Similar to44086b0, refactor heap scanning functions to be moresuitable for the read stream API.Author: Melanie PlagemanDiscussion:https://postgr.es/m/CAAKRu_YtXJiYKQvb5JsA2SkwrsizYLugs4sSOZh3EAjKUg=gEQ@mail.gmail.com
1 parent2a217c3 commit3a4a353

File tree

2 files changed

+55
-50
lines changed

2 files changed

+55
-50
lines changed

‎src/backend/access/heap/heapam.c

Lines changed: 54 additions & 49 deletions
Original file line numberDiff line numberDiff line change
@@ -83,6 +83,11 @@ static Bitmapset *HeapDetermineColumnsInfo(Relation relation,
8383
staticboolheap_acquire_tuplock(Relationrelation,ItemPointertid,
8484
LockTupleModemode,LockWaitPolicywait_policy,
8585
bool*have_tuple_lock);
86+
staticinlineBlockNumberheapgettup_advance_block(HeapScanDescscan,
87+
BlockNumberblock,
88+
ScanDirectiondir);
89+
staticpg_noinlineBlockNumberheapgettup_initial_block(HeapScanDescscan,
90+
ScanDirectiondir);
8691
staticvoidcompute_new_xmax_infomask(TransactionIdxmax,uint16old_infomask,
8792
uint16old_infomask2,TransactionIdadd_to_xmax,
8893
LockTupleModemode,boolis_update,
@@ -455,16 +460,14 @@ heap_prepare_pagescan(TableScanDesc sscan)
455460
}
456461

457462
/*
458-
*heapfetchbuf - read and pin thegiven MAIN_FORKNUMblocknumber.
463+
*heap_fetch_next_buffer - read and pin thenextblockfrom MAIN_FORKNUM.
459464
*
460-
* Read thespecified block of the scan relation into a buffer and pin that
461-
*bufferbefore saving it in the scan descriptor.
465+
* Read thenext block of the scan relation into a buffer and pin that buffer
466+
* before saving it in the scan descriptor.
462467
*/
463468
staticinlinevoid
464-
heapfetchbuf(HeapScanDescscan,BlockNumberblock)
469+
heap_fetch_next_buffer(HeapScanDescscan,ScanDirectiondir)
465470
{
466-
Assert(block<scan->rs_nblocks);
467-
468471
/* release previous scan buffer, if any */
469472
if (BufferIsValid(scan->rs_cbuf))
470473
{
@@ -479,10 +482,25 @@ heapfetchbuf(HeapScanDesc scan, BlockNumber block)
479482
*/
480483
CHECK_FOR_INTERRUPTS();
481484

482-
/* read page using selected strategy */
483-
scan->rs_cbuf=ReadBufferExtended(scan->rs_base.rs_rd,MAIN_FORKNUM,block,
484-
RBM_NORMAL,scan->rs_strategy);
485-
scan->rs_cblock=block;
485+
if (unlikely(!scan->rs_inited))
486+
{
487+
scan->rs_cblock=heapgettup_initial_block(scan,dir);
488+
489+
/* ensure rs_cbuf is invalid when we get InvalidBlockNumber */
490+
Assert(scan->rs_cblock!=InvalidBlockNumber||
491+
!BufferIsValid(scan->rs_cbuf));
492+
493+
scan->rs_inited= true;
494+
}
495+
else
496+
scan->rs_cblock=heapgettup_advance_block(scan,scan->rs_cblock,
497+
dir);
498+
499+
/* read block if valid */
500+
if (BlockNumberIsValid(scan->rs_cblock))
501+
scan->rs_cbuf=ReadBufferExtended(scan->rs_base.rs_rd,MAIN_FORKNUM,
502+
scan->rs_cblock,RBM_NORMAL,
503+
scan->rs_strategy);
486504
}
487505

488506
/*
@@ -492,7 +510,7 @@ heapfetchbuf(HeapScanDesc scan, BlockNumber block)
492510
* occur with empty tables and in parallel scans when parallel workers get all
493511
* of the pages before we can get a chance to get our first page.
494512
*/
495-
staticBlockNumber
513+
staticpg_noinlineBlockNumber
496514
heapgettup_initial_block(HeapScanDescscan,ScanDirectiondir)
497515
{
498516
Assert(!scan->rs_inited);
@@ -619,7 +637,7 @@ heapgettup_continue_page(HeapScanDesc scan, ScanDirection dir, int *linesleft,
619637
}
620638

621639
/*
622-
* heapgettup_advance_block - helper forheapgettup() and heapgettup_pagemode()
640+
* heapgettup_advance_block - helper forheap_fetch_next_buffer()
623641
*
624642
* Given the current block number, the scan direction, and various information
625643
* contained in the scan descriptor, calculate the BlockNumber to scan next
@@ -730,23 +748,13 @@ heapgettup(HeapScanDesc scan,
730748
ScanKeykey)
731749
{
732750
HeapTupletuple=&(scan->rs_ctup);
733-
BlockNumberblock;
734751
Pagepage;
735752
OffsetNumberlineoff;
736753
intlinesleft;
737754

738-
if (unlikely(!scan->rs_inited))
739-
{
740-
block=heapgettup_initial_block(scan,dir);
741-
/* ensure rs_cbuf is invalid when we get InvalidBlockNumber */
742-
Assert(block!=InvalidBlockNumber|| !BufferIsValid(scan->rs_cbuf));
743-
scan->rs_inited= true;
744-
}
745-
else
755+
if (likely(scan->rs_inited))
746756
{
747757
/* continue from previously returned page/tuple */
748-
block=scan->rs_cblock;
749-
750758
LockBuffer(scan->rs_cbuf,BUFFER_LOCK_SHARE);
751759
page=heapgettup_continue_page(scan,dir,&linesleft,&lineoff);
752760
gotocontinue_page;
@@ -756,9 +764,16 @@ heapgettup(HeapScanDesc scan,
756764
* advance the scan until we find a qualifying tuple or run out of stuff
757765
* to scan
758766
*/
759-
while (block!=InvalidBlockNumber)
767+
while (true)
760768
{
761-
heapfetchbuf(scan,block);
769+
heap_fetch_next_buffer(scan,dir);
770+
771+
/* did we run out of blocks to scan? */
772+
if (!BufferIsValid(scan->rs_cbuf))
773+
break;
774+
775+
Assert(BufferGetBlockNumber(scan->rs_cbuf)==scan->rs_cblock);
776+
762777
LockBuffer(scan->rs_cbuf,BUFFER_LOCK_SHARE);
763778
page=heapgettup_start_page(scan,dir,&linesleft,&lineoff);
764779
continue_page:
@@ -780,7 +795,7 @@ heapgettup(HeapScanDesc scan,
780795

781796
tuple->t_data= (HeapTupleHeader)PageGetItem(page,lpp);
782797
tuple->t_len=ItemIdGetLength(lpp);
783-
ItemPointerSet(&(tuple->t_self),block,lineoff);
798+
ItemPointerSet(&(tuple->t_self),scan->rs_cblock,lineoff);
784799

785800
visible=HeapTupleSatisfiesVisibility(tuple,
786801
scan->rs_base.rs_snapshot,
@@ -810,9 +825,6 @@ heapgettup(HeapScanDesc scan,
810825
* it's time to move to the next.
811826
*/
812827
LockBuffer(scan->rs_cbuf,BUFFER_LOCK_UNLOCK);
813-
814-
/* get the BlockNumber to scan next */
815-
block=heapgettup_advance_block(scan,block,dir);
816828
}
817829

818830
/* end of scan */
@@ -832,9 +844,9 @@ heapgettup(HeapScanDesc scan,
832844
*
833845
* The internal logic is much the same as heapgettup's too, but there are some
834846
* differences: we do not take the buffer content lock (that only needs to
835-
* happen insideheapgetpage), and we iterate through just the tuples listed
836-
* in rs_vistuples[] rather than all tuples on the page. Notice that
837-
* lineindex is 0-based, where the corresponding loop variable lineoff in
847+
* happen insideheap_prepare_pagescan), and we iterate through just the
848+
*tuples listedin rs_vistuples[] rather than all tuples on the page. Notice
849+
*thatlineindex is 0-based, where the corresponding loop variable lineoff in
838850
* heapgettup is 1-based.
839851
* ----------------
840852
*/
@@ -845,22 +857,13 @@ heapgettup_pagemode(HeapScanDesc scan,
845857
ScanKeykey)
846858
{
847859
HeapTupletuple=&(scan->rs_ctup);
848-
BlockNumberblock;
849860
Pagepage;
850861
intlineindex;
851862
intlinesleft;
852863

853-
if (unlikely(!scan->rs_inited))
854-
{
855-
block=heapgettup_initial_block(scan,dir);
856-
/* ensure rs_cbuf is invalid when we get InvalidBlockNumber */
857-
Assert(block!=InvalidBlockNumber|| !BufferIsValid(scan->rs_cbuf));
858-
scan->rs_inited= true;
859-
}
860-
else
864+
if (likely(scan->rs_inited))
861865
{
862866
/* continue from previously returned page/tuple */
863-
block=scan->rs_cblock;/* current page */
864867
page=BufferGetPage(scan->rs_cbuf);
865868

866869
lineindex=scan->rs_cindex+dir;
@@ -877,10 +880,15 @@ heapgettup_pagemode(HeapScanDesc scan,
877880
* advance the scan until we find a qualifying tuple or run out of stuff
878881
* to scan
879882
*/
880-
while (block!=InvalidBlockNumber)
883+
while (true)
881884
{
882-
/* read the page */
883-
heapfetchbuf(scan,block);
885+
heap_fetch_next_buffer(scan,dir);
886+
887+
/* did we run out of blocks to scan? */
888+
if (!BufferIsValid(scan->rs_cbuf))
889+
break;
890+
891+
Assert(BufferGetBlockNumber(scan->rs_cbuf)==scan->rs_cblock);
884892

885893
/* prune the page and determine visible tuple offsets */
886894
heap_prepare_pagescan((TableScanDesc)scan);
@@ -902,7 +910,7 @@ heapgettup_pagemode(HeapScanDesc scan,
902910

903911
tuple->t_data= (HeapTupleHeader)PageGetItem(page,lpp);
904912
tuple->t_len=ItemIdGetLength(lpp);
905-
ItemPointerSet(&(tuple->t_self),block,lineoff);
913+
ItemPointerSet(&(tuple->t_self),scan->rs_cblock,lineoff);
906914

907915
/* skip any tuples that don't match the scan key */
908916
if (key!=NULL&&
@@ -913,9 +921,6 @@ heapgettup_pagemode(HeapScanDesc scan,
913921
scan->rs_cindex=lineindex;
914922
return;
915923
}
916-
917-
/* get the BlockNumber to scan next */
918-
block=heapgettup_advance_block(scan,block,dir);
919924
}
920925

921926
/* end of scan */

‎src/backend/access/heap/heapam_handler.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2489,7 +2489,7 @@ heapam_scan_sample_next_tuple(TableScanDesc scan, SampleScanState *scanstate,
24892489
visible=SampleHeapTupleVisible(scan,hscan->rs_cbuf,
24902490
tuple,tupoffset);
24912491

2492-
/* in pagemode,heapgetpage did this for us */
2492+
/* in pagemode,heap_prepare_pagescan did this for us */
24932493
if (!pagemode)
24942494
HeapCheckForSerializableConflictOut(visible,scan->rs_rd,tuple,
24952495
hscan->rs_cbuf,scan->rs_snapshot);

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp