Bugfix. Do away with possible conflict of hooks, declared as 'extern' in different libraries.

To avoid such a problem in future, refactor AQO interfaces: declare all
hooks as static, reduce number of exporting functions and introduce
concept of *_init() function for a module that needs some actions in the
PG_init() routine.

Reviewed by: @Anisimov-ds

Author: danolivo

aqo.c

@@ -19,9 +19,7 @@
 
 #include "aqo.h"
 #include "aqo_shared.h"
-#include "cardinality_hooks.h"
 #include "path_utils.h"
-#include "preprocessing.h"
 #include "storage.h"
 
 
@@ -98,19 +96,6 @@ MemoryContext 		AQOLearnMemCtx = NULL;
 /* Additional plan info */
 int njoins;
 
-/* Saved hook values */
-post_parse_analyze_hook_type				prev_post_parse_analyze_hook;
-planner_hook_type							prev_planner_hook;
-ExecutorStart_hook_type						prev_ExecutorStart_hook;
-ExecutorRun_hook_type						prev_ExecutorRun;
-ExecutorEnd_hook_type						prev_ExecutorEnd_hook;
-set_baserel_rows_estimate_hook_type			prev_set_foreign_rows_estimate_hook;
-set_baserel_rows_estimate_hook_type			prev_set_baserel_rows_estimate_hook;
-get_parameterized_baserel_size_hook_type	prev_get_parameterized_baserel_size_hook;
-set_joinrel_size_estimates_hook_type		prev_set_joinrel_size_estimates_hook;
-get_parameterized_joinrel_size_hook_type	prev_get_parameterized_joinrel_size_hook;
-ExplainOnePlan_hook_type					prev_ExplainOnePlan_hook;
-ExplainOneNode_hook_type					prev_ExplainOneNode_hook;
 
 /*****************************************************************************
  *
@@ -324,6 +309,7 @@ _PG_init(void)
 							 NULL,
 							 NULL);
 
+<<<<<<< HEAD
 	prev_shmem_startup_hook						= shmem_startup_hook;
 	shmem_startup_hook							= aqo_init_shmem;
 	prev_planner_hook							= planner_hook;
@@ -360,6 +346,13 @@ _PG_init(void)
 
 	prev_create_upper_paths_hook				= create_upper_paths_hook;
 	create_upper_paths_hook						= aqo_store_upper_signature_hook;
+=======
+	aqo_shmem_init();
+	aqo_preprocessing_init();
+	aqo_postprocessing_init();
+	aqo_cardinality_hooks_init();
+	aqo_path_utils_init();
+>>>>>>> daf05a0 (Bugfix. Do away with possible conflict of hooks, declared as 'extern' in)
 
 	init_deactivated_queries_storage();
 

aqo.h

@@ -132,19 +132,16 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/pathnode.h"
 #include "optimizer/planner.h"
-#include "optimizer/cost.h"
 #include "parser/analyze.h"
 #include "parser/parsetree.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
-#include "utils/fmgroids.h"
 #include "utils/snapmgr.h"
 
 #include "machine_learning.h"
-//#include "storage.h"
 
 /* Check PostgreSQL version (9.6.0 contains important changes in planner) */
 #if PG_VERSION_NUM < 90600
@@ -237,58 +234,15 @@ extern MemoryContext AQOCacheMemCtx;
 extern MemoryContext AQOPredictMemCtx;
 extern MemoryContext AQOLearnMemCtx;
 
-/* Saved hook values in case of unload */
-extern post_parse_analyze_hook_type prev_post_parse_analyze_hook;
-extern planner_hook_type prev_planner_hook;
-extern ExecutorStart_hook_type prev_ExecutorStart_hook;
-extern ExecutorRun_hook_type prev_ExecutorRun;
-extern ExecutorEnd_hook_type prev_ExecutorEnd_hook;
-extern set_baserel_rows_estimate_hook_type
-										prev_set_foreign_rows_estimate_hook;
-extern set_baserel_rows_estimate_hook_type
-										prev_set_baserel_rows_estimate_hook;
-extern get_parameterized_baserel_size_hook_type
-									prev_get_parameterized_baserel_size_hook;
-extern set_joinrel_size_estimates_hook_type
-										prev_set_joinrel_size_estimates_hook;
-extern get_parameterized_joinrel_size_hook_type
-									prev_get_parameterized_joinrel_size_hook;
-extern ExplainOnePlan_hook_type prev_ExplainOnePlan_hook;
-extern ExplainOneNode_hook_type prev_ExplainOneNode_hook;
-
-extern void ppi_hook(ParamPathInfo *ppi);
 extern int aqo_statement_timeout;
 
-/* Hash functions */
-void get_eclasses(List *clauselist, int *nargs, int **args_hash,
-				  int **eclass_hash);
-int get_clause_hash(Expr *clause, int nargs, int *args_hash, int *eclass_hash);
-
-
-/* Storage interaction */
-extern bool load_fss_ext(uint64 fs, int fss, OkNNrdata *data, List **reloids);
-extern bool update_fss_ext(uint64 fs, int fss, OkNNrdata *data, List *reloids);
-
-/* Query preprocessing hooks */
-extern void print_into_explain(PlannedStmt *plannedstmt, IntoClause *into,
-							   ExplainState *es, const char *queryString,
-							   ParamListInfo params,
-							   const instr_time *planduration,
-							   QueryEnvironment *queryEnv);
-extern void print_node_explain(ExplainState *es, PlanState *ps, Plan *plan);
-
 /* Cardinality estimation */
 extern double predict_for_relation(List *restrict_clauses, List *selectivities,
 								   List *relsigns, int *fss);
 
-/* Query execution statistics collecting hooks */
-void aqo_ExecutorStart(QueryDesc *queryDesc, int eflags);
-void aqo_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction,
-					 uint64 count, bool execute_once);
-void aqo_ExecutorEnd(QueryDesc *queryDesc);
-
 /* Automatic query tuning */
 extern void automatical_query_tuning(uint64 query_hash, struct StatEntry *stat);
+extern double get_mean(double *elems, int nelems);
 
 /* Utilities */
 extern int int_cmp(const void *a, const void *b);
@@ -306,8 +260,10 @@ extern void selectivity_cache_clear(void);
 
 extern bool IsQueryDisabled(void);
 
-extern bool update_query_timeout(uint64 queryid, int64 smart_timeout);
-extern double get_mean(double *elems, int nelems);
-
 extern List *cur_classes;
+
+extern void aqo_cardinality_hooks_init(void);
+extern void aqo_preprocessing_init(void);
+extern void aqo_postprocessing_init(void);
+
 #endif

aqo_shared.c

@@ -6,27 +6,30 @@
 
 #include "lib/dshash.h"
 #include "miscadmin.h"
+#include "storage/ipc.h"
 #include "storage/shmem.h"
 
 #include "aqo_shared.h"
 #include "storage.h"
 
 
-shmem_startup_hook_type prev_shmem_startup_hook = NULL;
 AQOSharedState *aqo_state = NULL;
 int fs_max_items = 10000; /* Max number of different feature spaces in ML model */
 int fss_max_items = 100000; /* Max number of different feature subspaces in ML model */
 
+static shmem_startup_hook_type	aqo_shmem_startup_next = NULL;
+static shmem_request_hook_type	aqo_shmem_request_next = NULL;
+
 static void on_shmem_shutdown(int code, Datum arg);
 
-void
+static void
 aqo_init_shmem(void)
 {
 	bool		found;
 	HASHCTL		info;
 
-	if (prev_shmem_startup_hook)
-		prev_shmem_startup_hook();
+	if (aqo_shmem_startup_next)
+		aqo_shmem_startup_next();
 
 	aqo_state = NULL;
 	stat_htab = NULL;
@@ -116,10 +119,17 @@ on_shmem_shutdown(int code, Datum arg)
 	return;
 }
 
-Size
-aqo_memsize(void)
+
+/*
+ * Requests any additional shared memory required for aqo.
+ */
+static void
+aqo_shmem_request(void)
 {
-	Size		size;
+	Size	size;
+
+	if (aqo_shmem_request_next)
+		aqo_shmem_request_next();
 
 	size = MAXALIGN(sizeof(AQOSharedState));
 	size = add_size(size, hash_estimate_size(fs_max_items, sizeof(AQOSharedState)));
@@ -128,5 +138,14 @@ aqo_memsize(void)
 	size = add_size(size, hash_estimate_size(fss_max_items, sizeof(DataEntry)));
 	size = add_size(size, hash_estimate_size(fs_max_items, sizeof(QueriesEntry)));
 
-	return size;
+	RequestAddinShmemSpace(size);
+}
+
+void
+aqo_shmem_init(void)
+{
+	aqo_shmem_startup_next	= shmem_startup_hook;
+	shmem_startup_hook		= aqo_init_shmem;
+	aqo_shmem_request_next	= shmem_request_hook;
+	shmem_request_hook		= aqo_shmem_request;
 }

aqo_shared.h

@@ -1,9 +1,6 @@
 #ifndef AQO_SHARED_H
 #define AQO_SHARED_H
 
-#include "lib/dshash.h"
-#include "storage/dsm.h"
-#include "storage/ipc.h"
 #include "storage/lwlock.h"
 #include "utils/dsa.h"
 
@@ -31,13 +28,11 @@ typedef struct AQOSharedState
 } AQOSharedState;
 
 
-extern shmem_startup_hook_type prev_shmem_startup_hook;
 extern AQOSharedState *aqo_state;
 
 extern int fs_max_items; /* Max number of feature spaces that AQO can operate */
 extern int fss_max_items;
 
-extern Size aqo_memsize(void);
-extern void aqo_init_shmem(void);
+extern void aqo_shmem_init(void);
 
 #endif /* AQO_SHARED_H */