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pgstrom啥时候被启动

• 当开启服务器的时候
• src\backend\postmaster\postmaster.c:PostmasterMain

/*	 * process any libraries that should be preloaded at postmaster start	 */	process_shared_preload_libraries();

• 在这儿的时候，pgstrom就被启动了
  • 然后就执行了void _PG_init(void)

/* * _PG_init * * Main entrypoint of PG-Strom. It shall be invoked only once when postmaster * process is starting up, then it calls other sub-systems to initialize for each ones. */void_PG_init(void){
   	/*	 * PG-Strom has to be loaded using shared_preload_libraries option	 */	if (!process_shared_preload_libraries_in_progress)		ereport(ERROR,				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),		errmsg("PG-Strom must be loaded via shared_preload_libraries")));	/* link nvrtc library according to the current CUDA version */	pgstrom_init_nvrtc();	/* dump version number */#ifdef PGSTROM_VERSION	elog(LOG, "PG-Strom version %s built for PostgreSQL %s",		 PGSTROM_VERSION, PG_MAJORVERSION);#else	elog(LOG, "PG-Strom built for PostgreSQL %s", PG_MAJORVERSION);#endif	/* init misc variables */	PAGE_SIZE = sysconf(_SC_PAGESIZE);	PAGE_MASK = PAGE_SIZE - 1;	PAGE_SHIFT = get_next_log2(PAGE_SIZE);	PHYS_PAGES = sysconf(_SC_PHYS_PAGES);	/* init GPU/CUDA infrastracture */	pgstrom_init_common_guc();	pgstrom_init_shmbuf();	pgstrom_init_gpu_device();	pgstrom_init_gpu_mmgr();	pgstrom_init_gpu_context();	pgstrom_init_cuda_program();	pgstrom_init_nvme_strom();	pgstrom_init_codegen();	/* init custom-scan providers/FDWs */	pgstrom_init_gputasks();	pgstrom_init_gpuscan();	pgstrom_init_gpujoin();	pgstrom_init_inners();	pgstrom_init_gpupreagg();	pgstrom_init_relscan();	pgstrom_init_arrow_fdw();	/* check commercial license, if any */	check_heterodb_license();	/* dummy custom-scan node */	memset(&pgstrom_dummy_path_methods, 0, sizeof(CustomPathMethods));	pgstrom_dummy_path_methods.CustomName	= "Dummy";	pgstrom_dummy_path_methods.PlanCustomPath		= pgstrom_dummy_create_plan;	memset(&pgstrom_dummy_plan_methods, 0, sizeof(CustomScanMethods));	pgstrom_dummy_plan_methods.CustomName	= "Dummy";	pgstrom_dummy_plan_methods.CreateCustomScanState		= pgstrom_dummy_create_scan_state;	/* planner hook registration */	planner_hook_next = planner_hook;	planner_hook = pgstrom_post_planner;}

举例：如何添加GPUscan结点到生成计划里面？

/* * set_base_rel_pathlists *	  Finds all paths available for scanning each base-relation entry. *	  Sequential scan and any available indices are considered. *	  Each useful path is attached to its relation's 'pathlist' field. */static voidset_base_rel_pathlists(PlannerInfo *root){
   	Index		rti;	for (rti = 1; rti < root->simple_rel_array_size; rti++)	{
   		RelOptInfo *rel = root->simple_rel_array[rti];		/* there may be empty slots corresponding to non-baserel RTEs */		if (rel == NULL)			continue;		Assert(rel->relid == rti);	/* sanity check on array */		/* ignore RTEs that are "other rels" */		if (rel->reloptkind != RELOPT_BASEREL)			continue;		set_rel_pathlist(root, rel, rti, root->simple_rte_array[rti]);	}}

set_rel_pathlist

/* * set_rel_pathlist *	  Build access paths for a base relation */static voidset_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,				 Index rti, RangeTblEntry *rte){
   	if (IS_DUMMY_REL(rel))	{
   		/* We already proved the relation empty, so nothing more to do */	}	else if (rte->inh)	{
   		/* It's an "append relation", process accordingly */		set_append_rel_pathlist(root, rel, rti, rte);	}	else	{
   		switch (rel->rtekind)		{
   			case RTE_RELATION:				if (rte->relkind == RELKIND_FOREIGN_TABLE)				{
   					/* Foreign table */					set_foreign_pathlist(root, rel, rte);				}				else if (rte->tablesample != NULL)				{
   					/* Sampled relation */					set_tablesample_rel_pathlist(root, rel, rte);				}				else				{
   					/* Plain relation */					set_plain_rel_pathlist(root, rel, rte);				}				break;			case RTE_SUBQUERY:				/* Subquery --- fully handled during set_rel_size */				break;			case RTE_FUNCTION:				/* RangeFunction */				set_function_pathlist(root, rel, rte);				break;			case RTE_TABLEFUNC:				/* Table Function */				set_tablefunc_pathlist(root, rel, rte);				break;			case RTE_VALUES:				/* Values list */				set_values_pathlist(root, rel, rte);				break;			case RTE_CTE:				/* CTE reference --- fully handled during set_rel_size */				break;			case RTE_NAMEDTUPLESTORE:				/* tuplestore reference --- fully handled during set_rel_size */				break;			default:				elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);				break;		}	}	/*	 * Allow a plugin to editorialize on the set of Paths for this base	 * relation.  It could add new paths (such as CustomPaths) by calling	 * add_path(), or add_partial_path() if parallel aware.  It could also	 * delete or modify paths added by the core code.	 */	if (set_rel_pathlist_hook)		(*set_rel_pathlist_hook) (root, rel, rti, rte);	/*	 * If this is a baserel, we should normally consider gathering any partial	 * paths we may have created for it.  We have to do this after calling the	 * set_rel_pathlist_hook, else it cannot add partial paths to be included	 * here.	 *	 * However, if this is an inheritance child, skip it.  Otherwise, we could	 * end up with a very large number of gather nodes, each trying to grab	 * its own pool of workers.  Instead, we'll consider gathering partial	 * paths for the parent appendrel.	 *	 * Also, if this is the topmost scan/join rel (that is, the only baserel),	 * we postpone gathering until the final scan/join targetlist is available	 * (see grouping_planner).	 */	if (rel->reloptkind == RELOPT_BASEREL &&		bms_membership(root->all_baserels) != BMS_SINGLETON)		generate_gather_paths(root, rel, false);	/* Now find the cheapest of the paths for this rel */	set_cheapest(rel);#ifdef OPTIMIZER_DEBUG	debug_print_rel(root, rel);#endif}

• 以CustomPath的形式加入GPUscanpath

pgstrom_init_gpuscan();

/* * pgstrom_init_gpuscan */voidpgstrom_init_gpuscan(void){
   	/* pg_strom.enable_gpuscan */	DefineCustomBoolVariable("pg_strom.enable_gpuscan",							 "Enables the use of GPU accelerated full-scan",							 NULL,							 &enable_gpuscan,							 true,							 PGC_USERSET,							 GUC_NOT_IN_SAMPLE,							 NULL, NULL, NULL);	/* pg_strom.pullup_outer_scan */	DefineCustomBoolVariable("pg_strom.pullup_outer_scan",							 "Enables to pull up simple outer scan",							 NULL,							 &enable_pullup_outer_scan,							 true,							 PGC_USERSET,                             GUC_NOT_IN_SAMPLE,                             NULL, NULL, NULL);	/* setup path methods */	memset(&gpuscan_path_methods, 0, sizeof(gpuscan_path_methods));	gpuscan_path_methods.CustomName			= "GpuScan";	gpuscan_path_methods.PlanCustomPath		= PlanGpuScanPath;	/* setup plan methods */	memset(&gpuscan_plan_methods, 0, sizeof(gpuscan_plan_methods));	gpuscan_plan_methods.CustomName			= "GpuScan";	gpuscan_plan_methods.CreateCustomScanState = gpuscan_create_scan_state;	RegisterCustomScanMethods(&gpuscan_plan_methods);	/* setup exec methods */	memset(&gpuscan_exec_methods, 0, sizeof(gpuscan_exec_methods));	gpuscan_exec_methods.CustomName         = "GpuScan";	gpuscan_exec_methods.BeginCustomScan    = ExecInitGpuScan;	gpuscan_exec_methods.ExecCustomScan     = ExecGpuScan;	gpuscan_exec_methods.EndCustomScan      = ExecEndGpuScan;	gpuscan_exec_methods.ReScanCustomScan   = ExecReScanGpuScan;	gpuscan_exec_methods.EstimateDSMCustomScan = ExecGpuScanEstimateDSM;	gpuscan_exec_methods.InitializeDSMCustomScan = ExecGpuScanInitDSM;	gpuscan_exec_methods.InitializeWorkerCustomScan = ExecGpuScanInitWorker;	gpuscan_exec_methods.ReInitializeDSMCustomScan = ExecGpuScanReInitializeDSM;	gpuscan_exec_methods.ShutdownCustomScan	= ExecShutdownGpuScan;	gpuscan_exec_methods.ExplainCustomScan  = ExplainGpuScan;	/* hook registration */	set_rel_pathlist_next = set_rel_pathlist_hook;	set_rel_pathlist_hook = gpuscan_add_scan_path;}

gpuscan_add_scan_path;

/* * gpuscan_add_scan_path - entrypoint of the set_rel_pathlist_hook */static voidgpuscan_add_scan_path(PlannerInfo *root,					  RelOptInfo *baserel,					  Index rtindex,					  RangeTblEntry *rte){
   	Path	   *pathnode;	List	   *dev_quals = NIL;	List	   *host_quals = NIL;	IndexOptInfo *indexOpt;	List	   *indexConds;	List	   *indexQuals;	cl_long		indexNBlocks;	ListCell   *lc;	/* call the secondary hook */	if (set_rel_pathlist_next)		set_rel_pathlist_next(root, baserel, rtindex, rte);	/* nothing to do, if either PG-Strom or GpuScan is not enabled */	if (!pgstrom_enabled || !enable_gpuscan)		return;	/* We already proved the relation empty, so nothing more to do */	if (is_dummy_rel(baserel))		return;	/* It is the role of built-in Append node */	if (rte->inh)		return;	/*	 * GpuScan can run on only base relations or foreign table managed	 * by arrow_fdw.	 */	if (rte->relkind == RELKIND_FOREIGN_TABLE)	{
   		if (!baseRelIsArrowFdw(baserel))			return;	}	else if (rte->relkind != RELKIND_RELATION &&			 rte->relkind != RELKIND_MATVIEW)		return;	/* Check whether the qualifier can run on GPU device */	foreach (lc, baserel->baserestrictinfo)	{
   		RestrictInfo   *rinfo = lfirst(lc);		if (pgstrom_device_expression(root, baserel, rinfo->clause))			dev_quals = lappend(dev_quals, rinfo);		else			host_quals = lappend(host_quals, rinfo);	}	if (dev_quals == NIL)		return;	/* Check availability of GpuScan+BRIN Index */	indexOpt = pgstrom_tryfind_brinindex(root, baserel,										 &indexConds,										 &indexQuals,										 &indexNBlocks);	/* add GpuScan path in single process */	pathnode = create_gpuscan_path(root, baserel,								   dev_quals,								   host_quals,								   0,								   indexOpt,								   indexConds,								   indexQuals,								   indexNBlocks);	add_path(baserel, pathnode);	/* If appropriate, consider parallel GpuScan */	if (baserel->consider_parallel && baserel->lateral_relids == NULL)	{
   		int		parallel_nworkers			= compute_parallel_worker(baserel,									  baserel->pages, -1.0,									  max_parallel_workers_per_gather);		/*		 * XXX - Do we need a something specific logic for GpuScan to adjust		 * parallel_workers.		 */		if (parallel_nworkers <= 0)			return;		/* add GpuScan path performing on parallel workers */		pathnode = create_gpuscan_path(root, baserel,									   dev_quals,									   host_quals,									   parallel_nworkers,									   indexOpt,									   indexConds,									   indexQuals,									   indexNBlocks);		add_partial_path(baserel, pathnode);	}}

pg提供了一些变量可以实现把

• 以后的优化函数就不是standard_planner啦！

static PlannedStmt *pgstrom_post_planner(Query *parse,int cursorOptions,ParamListInfo boundParams){
   	PlannedStmt	   *pstmt;	ListCell	   *lc;	if (planner_hook_next)		pstmt = planner_hook_next(parse, cursorOptions, boundParams);	else		pstmt = standard_planner(parse, cursorOptions, boundParams);	pgstrom_post_planner_recurse(pstmt, &pstmt->planTree);	foreach (lc, pstmt->subplans)		pgstrom_post_planner_recurse(pstmt, (Plan **)&lfirst(lc));	return pstmt;}

/* * pgstrom_post_planner * * remove 'dummy' custom scan node. */static voidpgstrom_post_planner_recurse(PlannedStmt *pstmt, Plan **p_plan){
   	Plan	   *plan = *p_plan;	ListCell   *lc;	Assert(plan != NULL);	switch (nodeTag(plan))	{
   		case T_ModifyTable:			{
   				ModifyTable *splan = (ModifyTable *) plan;				foreach (lc, splan->plans)					pgstrom_post_planner_recurse(pstmt, (Plan **)&lfirst(lc));			}			break;		case T_Append:			{
   				Append	   *splan = (Append *) plan;				foreach (lc, splan->appendplans)					pgstrom_post_planner_recurse(pstmt, (Plan **)&lfirst(lc));			}			break;		case T_MergeAppend:			{
   				MergeAppend *splan = (MergeAppend *) plan;				foreach (lc, splan->mergeplans)					pgstrom_post_planner_recurse(pstmt, (Plan **)&lfirst(lc));			}			break;		case T_BitmapAnd:			{
   				BitmapAnd  *splan = (BitmapAnd *) plan;				foreach (lc, splan->bitmapplans)					pgstrom_post_planner_recurse(pstmt, (Plan **)&lfirst(lc));			}			break;		case T_BitmapOr:			{
   				BitmapOr   *splan = (BitmapOr *) plan;				foreach (lc, splan->bitmapplans)					pgstrom_post_planner_recurse(pstmt, (Plan **)&lfirst(lc));			}			break;		case T_SubqueryScan:			{
   				SubqueryScan *sscan = (SubqueryScan *) plan;				pgstrom_post_planner_recurse(pstmt, &sscan->subplan);			}			break;		case T_CustomScan:			{
   				CustomScan *cscan = (CustomScan *) plan;				if (cscan->methods == &pgstrom_dummy_plan_methods)				{
   					*p_plan = pgstrom_dummy_remove_plan(pstmt, cscan);					pgstrom_post_planner_recurse(pstmt, p_plan);					return;				}				else if (pgstrom_plan_is_gpupreagg(&cscan->scan.plan))					gpupreagg_post_planner(pstmt, cscan);				foreach (lc, cscan->custom_plans)					pgstrom_post_planner_recurse(pstmt, (Plan **)&lfirst(lc));			}			break;		default:			break;	}	if (plan->lefttree)		pgstrom_post_planner_recurse(pstmt, &plan->lefttree);	if (plan->righttree)		pgstrom_post_planner_recurse(pstmt, &plan->righttree);}

重要连接

• https://blog.csdn.net/weixin_40730091/article/details/102734600?depth_1-utm_source=distribute.pc_relevant.none-task&utm_source=distribute.pc_relevant.none-task

重要连接的例子

SELECT cat, count(*), avg(ax) FROM t0 NATURAL JOIN t1 NATURAL JOIN t2 NATURAL JOIN t3 NATURAL JOIN t4 NATURAL JOIN t5 NATURAL JOIN t6 NATURAL JOIN t7 NATURAL JOIN t8 GROUP BY cat;

HashAggregate  (cost=3529132.25..3529132.57 rows=26 width=12)  Output: t0.cat, pgstrom.count((pgstrom.nrows())), pgstrom.avg((pgstrom.nrows((t1.ax IS NOT NULL))), (pgstrom.psum(t1.ax)))  Group Key: t0.cat  ->  Custom Scan (GpuPreAgg)  (cost=29099.24..2859511.64 rows=234 width=48)        Output: t0.cat, pgstrom.nrows(), pgstrom.nrows((t1.ax IS NOT NULL)), pgstrom.psum(t1.ax)        Reduction: Local + Global        GPU Projection: t0.cat, t1.ax        Logic Parameter: SafetyLimit: 2147483647, KeyDistSalt: 9        Extra: outer-bulk-exec        ->  Custom Scan (GpuJoin) on public.t0  (cost=25099.24..2826221.34 rows=93721454 width=12)              Output: t0.cat, t1.ax              GPU Projection: t0.cat::text, t1.ax::double precision              Depth 1: GpuHashJoin, HashKeys: (t0.fid)                       JoinQuals: (t0.fid = t6.fid)                       Nrows (in/out: 97.75%), KDS-Hash (size: 13.47MB, nbatches: 1)              Depth 2: GpuHashJoin, HashKeys: (t0.cid)                       JoinQuals: (t0.cid = t3.cid)                       Nrows (in/out: 98.34%), KDS-Hash (size: 13.47MB, nbatches: 1)              Depth 3: GpuHashJoin, HashKeys: (t0.bid)                       JoinQuals: (t0.bid = t2.bid)                       Nrows (in/out: 98.76%), KDS-Hash (size: 13.47MB, nbatches: 1)              Depth 4: GpuHashJoin, HashKeys: (t0.eid)                       JoinQuals: (t0.eid = t5.eid)                       Nrows (in/out: 98.97%), KDS-Hash (size: 13.47MB, nbatches: 1)              Depth 5: GpuHashJoin, HashKeys: (t0.aid)                       JoinQuals: (t0.aid = t1.aid)                       Nrows (in/out: 100.00%), KDS-Hash (size: 13.47MB, nbatches: 1)              Depth 6: GpuHashJoin, HashKeys: (t0.did)                       JoinQuals: (t0.did = t4.did)                       Nrows (in/out: 100.00%), KDS-Hash (size: 13.47MB, nbatches: 1)              Depth 7: GpuHashJoin, HashKeys: (t0.gid)                       JoinQuals: (t0.gid = t7.gid)                       Nrows (in/out: 100.00%), KDS-Hash (size: 13.47MB, nbatches: 1)              Depth 8: GpuHashJoin, HashKeys: (t0.hid)                       JoinQuals: (t0.hid = t8.hid)                       Nrows (in/out: 99.74%), KDS-Hash (size: 13.47MB, nbatches: 1)              Extra: bulk-exec-support, row-format              ->  Seq Scan on public.t6  (cost=0.00..1935.00 rows=100000 width=4)                    Output: t6.fid, t6.ftext, t6.fx              ->  Seq Scan on public.t3  (cost=0.00..1935.00 rows=100000 width=4)                    Output: t3.cid, t3.ctext, t3.cx              ->  Seq Scan on public.t2  (cost=0.00..1935.00 rows=100000 width=4)                    Output: t2.bid, t2.btext, t2.bx              ->  Seq Scan on public.t5  (cost=0.00..1935.00 rows=100000 width=4)                    Output: t5.eid, t5.etext, t5.ex              ->  Seq Scan on public.t1  (cost=0.00..1935.00 rows=100000 width=12)                    Output: t1.aid, t1.atext, t1.ax              ->  Seq Scan on public.t4  (cost=0.00..1935.00 rows=100000 width=4)                    Output: t4.did, t4.dtext, t4.dx              ->  Seq Scan on public.t7  (cost=0.00..1935.00 rows=100000 width=4)                    Output: t7.gid, t7.gtext, t7.gx              ->  Seq Scan on public.t8  (cost=0.00..1935.00 rows=100000 width=4)                    Output: t8.hid, t8.htext, t8.hx

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