external
/
citus
mirror of https://github.com/citusdata/citus.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Multiply ColumnarCustomScan cost by tblspace.seqpage cost

pull/5090/head
Onur Tirtir 2021-07-05 17:52:56 +03:00
parent dba8421453
commit 8adcf2096b
1 changed files with 21 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
src/backend/columnar/columnar_customscan.c
View File

@ -23,6 +23,7 @@
#include "optimizer/paths.h" #include "optimizer/paths.h"
#include "optimizer/restrictinfo.h" #include "optimizer/restrictinfo.h"
#include "utils/relcache.h" #include "utils/relcache.h"
#include "utils/spccache.h"
#include "columnar/columnar_customscan.h" #include "columnar/columnar_customscan.h"
#include "columnar/columnar_metadata.h" #include "columnar/columnar_metadata.h"
@ -60,8 +61,8 @@ static void RemovePathsByPredicate(RelOptInfo *rel, PathPredicate removePathPred
static bool IsNotIndexPath(Path *path); static bool IsNotIndexPath(Path *path);
static Path * CreateColumnarScanPath(PlannerInfo *root, RelOptInfo *rel, static Path * CreateColumnarScanPath(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte); RangeTblEntry *rte);
static Cost ColumnarScanCost(Oid relationId, int numberOfColumnsRead); static Cost ColumnarScanCost(RelOptInfo *rel, Oid relationId, int numberOfColumnsRead);
static Cost ColumnarPerStripeScanCost(Oid relationId, static Cost ColumnarPerStripeScanCost(RelOptInfo *rel, Oid relationId,
int numberOfColumnsRead); int numberOfColumnsRead);
static uint64 ColumnarTableStripeCount(Oid relationId); static uint64 ColumnarTableStripeCount(Oid relationId);
static Plan * ColumnarScanPath_PlanCustomPath(PlannerInfo *root, static Plan * ColumnarScanPath_PlanCustomPath(PlannerInfo *root,
@ -270,7 +271,7 @@ CreateColumnarScanPath(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
path->startup_cost = 0; path->startup_cost = 0;
int numberOfColumnsRead = bms_num_members(rte->selectedCols); int numberOfColumnsRead = bms_num_members(rte->selectedCols);
path->total_cost = path->startup_cost + path->total_cost = path->startup_cost +
ColumnarScanCost(rte->relid, numberOfColumnsRead); ColumnarScanCost(rel, rte->relid, numberOfColumnsRead);
return (Path *) cspath; return (Path *) cspath;
} }
@ -282,10 +283,10 @@ CreateColumnarScanPath(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
* need to be read. * need to be read.
*/ */
static Cost static Cost
ColumnarScanCost(Oid relationId, int numberOfColumnsRead) ColumnarScanCost(RelOptInfo *rel, Oid relationId, int numberOfColumnsRead)
{ {
return ColumnarTableStripeCount(relationId) * return ColumnarTableStripeCount(relationId) *
ColumnarPerStripeScanCost(relationId, numberOfColumnsRead); ColumnarPerStripeScanCost(rel, relationId, numberOfColumnsRead);
} }
@ -295,7 +296,7 @@ ColumnarScanCost(Oid relationId, int numberOfColumnsRead)
* read during scan operation. * read during scan operation.
*/ */
static Cost static Cost
ColumnarPerStripeScanCost(Oid relationId, int numberOfColumnsRead) ColumnarPerStripeScanCost(RelOptInfo *rel, Oid relationId, int numberOfColumnsRead)
{ {
Relation relation = RelationIdGetRelation(relationId); Relation relation = RelationIdGetRelation(relationId);
List *stripeList = StripesForRelfilenode(relation->rd_node); List *stripeList = StripesForRelfilenode(relation->rd_node);
@ -324,6 +325,20 @@ ColumnarPerStripeScanCost(Oid relationId, int numberOfColumnsRead)
double columnSelectionRatio = numberOfColumnsRead / (double) maxColumnCount; double columnSelectionRatio = numberOfColumnsRead / (double) maxColumnCount;
Cost tableScanCost = (double) totalStripeSize / BLCKSZ * columnSelectionRatio; Cost tableScanCost = (double) totalStripeSize / BLCKSZ * columnSelectionRatio;
Cost perStripeScanCost = tableScanCost / list_length(stripeList); Cost perStripeScanCost = tableScanCost / list_length(stripeList);
/*
* Finally, multiply the cost of reading a single stripe by seq page read
* cost to make our estimation scale compatible with postgres.
* Since we are calculating the cost for a single stripe here, we use seq
* page cost instead of random page cost. This is because, random page
* access only happens when switching between columns, which is pretty
* much neglactable.
*/
double relSpaceSeqPageCost;
get_tablespace_page_costs(rel->reltablespace,
NULL, &relSpaceSeqPageCost);
perStripeScanCost = perStripeScanCost * relSpaceSeqPageCost;
return perStripeScanCost; return perStripeScanCost;
} }