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Commit7f44ede

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tableam: Don't assume that every AM uses md.c style storage.
Previously various parts of the code routed size requests throughRelationGetNumberOfBlocks[InFork]. That works if md.c is used by theAM, but not otherwise.Add a tableam callback to return the size of the table. As not everyAM will use postgres' BLCKSZ, have it return bytes, and haveRelationGetNumberOfBlocksInFork() round the byte size up into blocks.To allow code outside of the AM to determine the actual relation sizemap InvalidForkNumber the total size of a relation, as not every AMmight just need the postgres defined forks.A few users of RelationGetNumberOfBlocks() ought to be converted awayfrom that. One case, the use of it to determine whether a tid isvalid, will be fixed in a follow up commit. Others will have to waitfor v13.Author: Andres FreundDiscussion:https://postgr.es/m/20190423225201.3bbv6tbqzkb5w7cw@alap3.anarazel.de
1 parent6630cca commit7f44ede

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4 files changed

+110
-3
lines changed

4 files changed

+110
-3
lines changed

‎src/backend/access/heap/heapam_handler.c

Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1975,6 +1975,31 @@ heapam_scan_get_blocks_done(HeapScanDesc hscan)
19751975
}
19761976

19771977

1978+
/* ------------------------------------------------------------------------
1979+
* Miscellaneous callbacks for the heap AM
1980+
* ------------------------------------------------------------------------
1981+
*/
1982+
1983+
staticuint64
1984+
heapam_relation_size(Relationrel,ForkNumberforkNumber)
1985+
{
1986+
uint64nblocks=0;
1987+
1988+
/* Open it at the smgr level if not already done */
1989+
RelationOpenSmgr(rel);
1990+
1991+
/* InvalidForkNumber indicates returning the size for all forks */
1992+
if (forkNumber==InvalidForkNumber)
1993+
{
1994+
for (inti=0;i<MAX_FORKNUM;i++)
1995+
nblocks+=smgrnblocks(rel->rd_smgr,i);
1996+
}
1997+
else
1998+
nblocks=smgrnblocks(rel->rd_smgr,forkNumber);
1999+
2000+
returnnblocks*BLCKSZ;
2001+
}
2002+
19782003

19792004
/* ------------------------------------------------------------------------
19802005
* Planner related callbacks for the heap AM
@@ -2556,6 +2581,8 @@ static const TableAmRoutine heapam_methods = {
25562581
.index_build_range_scan=heapam_index_build_range_scan,
25572582
.index_validate_scan=heapam_index_validate_scan,
25582583

2584+
.relation_size=heapam_relation_size,
2585+
25592586
.relation_estimate_size=heapam_estimate_rel_size,
25602587

25612588
.scan_bitmap_next_block=heapam_scan_bitmap_next_block,

‎src/backend/access/table/tableamapi.c

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -86,6 +86,9 @@ GetTableAmRoutine(Oid amhandler)
8686
Assert(routine->scan_analyze_next_tuple!=NULL);
8787
Assert(routine->index_build_range_scan!=NULL);
8888
Assert(routine->index_validate_scan!=NULL);
89+
90+
Assert(routine->relation_size!=NULL);
91+
8992
Assert(routine->relation_estimate_size!=NULL);
9093

9194
/* optional, but one callback implies presence of hte other */

‎src/backend/storage/buffer/bufmgr.c

Lines changed: 40 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -33,6 +33,7 @@
3333
#include<sys/file.h>
3434
#include<unistd.h>
3535

36+
#include"access/tableam.h"
3637
#include"access/xlog.h"
3738
#include"catalog/catalog.h"
3839
#include"catalog/storage.h"
@@ -2789,14 +2790,50 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
27892790
/*
27902791
* RelationGetNumberOfBlocksInFork
27912792
*Determines the current number of pages in the specified relation fork.
2793+
*
2794+
* Note that the accuracy of the result will depend on the details of the
2795+
* relation's storage. For builtin AMs it'll be accurate, but for external AMs
2796+
* it might not be.
27922797
*/
27932798
BlockNumber
27942799
RelationGetNumberOfBlocksInFork(Relationrelation,ForkNumberforkNum)
27952800
{
2796-
/* Open it at the smgr level if not already done */
2797-
RelationOpenSmgr(relation);
2801+
switch (relation->rd_rel->relkind)
2802+
{
2803+
caseRELKIND_SEQUENCE:
2804+
caseRELKIND_INDEX:
2805+
caseRELKIND_PARTITIONED_INDEX:
2806+
/* Open it at the smgr level if not already done */
2807+
RelationOpenSmgr(relation);
2808+
2809+
returnsmgrnblocks(relation->rd_smgr,forkNum);
2810+
2811+
caseRELKIND_RELATION:
2812+
caseRELKIND_TOASTVALUE:
2813+
caseRELKIND_MATVIEW:
2814+
{
2815+
/*
2816+
* Not every table AM uses BLCKSZ wide fixed size
2817+
* blocks. Therefore tableam returns the size in bytes - but
2818+
* for the purpose of this routine, we want the number of
2819+
* blocks. Therefore divide, rounding up.
2820+
*/
2821+
uint64szbytes;
2822+
2823+
szbytes=table_relation_size(relation,forkNum);
2824+
2825+
return (szbytes+ (BLCKSZ-1)) /BLCKSZ;
2826+
}
2827+
caseRELKIND_VIEW:
2828+
caseRELKIND_COMPOSITE_TYPE:
2829+
caseRELKIND_FOREIGN_TABLE:
2830+
caseRELKIND_PARTITIONED_TABLE:
2831+
default:
2832+
Assert(false);
2833+
break;
2834+
}
27982835

2799-
returnsmgrnblocks(relation->rd_smgr,forkNum);
2836+
return0;/* keep compiler quiet */
28002837
}
28012838

28022839
/*

‎src/include/access/tableam.h

Lines changed: 40 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -540,6 +540,22 @@ typedef struct TableAmRoutine
540540
structValidateIndexState*state);
541541

542542

543+
/* ------------------------------------------------------------------------
544+
* Miscellaneous functions.
545+
* ------------------------------------------------------------------------
546+
*/
547+
548+
/*
549+
* See table_relation_size().
550+
*
551+
* Note that currently a few callers use the MAIN_FORKNUM size to vet the
552+
* validity of tids (e.g. nodeTidscans.c), and others use it to figure out
553+
* the range of potentially interesting blocks (brin, analyze). The
554+
* abstraction around this will need to be improved in the near future.
555+
*/
556+
uint64(*relation_size) (Relationrel,ForkNumberforkNumber);
557+
558+
543559
/* ------------------------------------------------------------------------
544560
* Planner related functions.
545561
* ------------------------------------------------------------------------
@@ -550,6 +566,10 @@ typedef struct TableAmRoutine
550566
*
551567
* While block oriented, it shouldn't be too hard for an AM that doesn't
552568
* doesn't internally use blocks to convert into a usable representation.
569+
*
570+
* This differs from the relation_size callback by returning size
571+
* estimates (both relation size and tuple count) for planning purposes,
572+
* rather than returning a currently correct estimate.
553573
*/
554574
void(*relation_estimate_size) (Relationrel,int32*attr_widths,
555575
BlockNumber*pages,double*tuples,
@@ -1503,6 +1523,26 @@ table_index_validate_scan(Relation heap_rel,
15031523
}
15041524

15051525

1526+
/* ----------------------------------------------------------------------------
1527+
* Miscellaneous functionality
1528+
* ----------------------------------------------------------------------------
1529+
*/
1530+
1531+
/*
1532+
* Return the current size of `rel` in bytes. If `forkNumber` is
1533+
* InvalidForkNumber, return the relation's overall size, otherwise the size
1534+
* for the indicated fork.
1535+
*
1536+
* Note that the overall size might not be the equivalent of the sum of sizes
1537+
* for the individual forks for some AMs, e.g. because the AMs storage does
1538+
* not neatly map onto the builtin types of forks.
1539+
*/
1540+
staticinlineuint64
1541+
table_relation_size(Relationrel,ForkNumberforkNumber)
1542+
{
1543+
returnrel->rd_tableam->relation_size(rel,forkNumber);
1544+
}
1545+
15061546
/* ----------------------------------------------------------------------------
15071547
* Planner related functionality
15081548
* ----------------------------------------------------------------------------

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