Add hierarchical memory context for saving datas not

to use postgres memory contexts except situation when AQO prediction which is passed on to the optimizer. We add three additional memory context for managing memory. AQOMemoryContext is renamed as AQOCacheMemCtx and containe as in the previous time environment data. During predict for plan nodes all of palloc is saved into AQO Predict Memory Context and clean up in the execution stage of query. After executing query we collect some long lived information until it is put into AQO knowledge table. All of them are saved in AQO Learn Memory Context. During these stages we calculates hashes from having got clause, selectivity arrays and relid lists. These tactical information is short-lived, so we save it in the AQO Utility Memory Context. We clean up Utility Memory Context inside calculated function or immediately after her having completed.

Author: Alena Rybakina

aqo.c

@@ -81,9 +81,23 @@ double log_selectivity_lower_bound = -30;
 * Currently we use it only to store query_text string which is initialized
 * after a query parsing and is used during the query planning.
 */
-MemoryContext AQOMemoryContext;
-MemoryContext AQO_cache_mem_ctx;
+
 QueryContextData	query_context;
+
+MemoryContext AQOTopMemCtx = NULL;
+
+/* Is released at the end of transaction */
+MemoryContext AQOCacheMemCtx = NULL;
+
+/* Should be released in-place, just after a huge calculation */
+MemoryContext AQOUtilityMemCtx = NULL;
+
+/* Is released at the end of planning */
+MemoryContext AQOPredictMemCtx = NULL;
+
+/* Is released at the end of learning */
+MemoryContext AQOLearnMemCtx = NULL;
+
 /* Additional plan info */
 int njoins;
 
@@ -119,7 +133,7 @@ aqo_free_callback(ResourceReleasePhase phase,
 
 if (isTopLevel)
 {
-list_free_deep(cur_classes);
+MemoryContextReset(AQOCacheMemCtx);
 cur_classes = NIL;
 }
 }
@@ -320,12 +334,42 @@ _PG_init(void)
 shmem_request_hook = aqo_shmem_request;
 
 init_deactivated_queries_storage();
-AQOMemoryContext = AllocSetContextCreate(TopMemoryContext,
-"AQOMemoryContext",
+
+/*
+* Create own Top memory Context for reporting AQO memory in the future.
+*/
+AQOTopMemCtx = AllocSetContextCreate(TopMemoryContext,
+"AQOTopMemoryContext",
 ALLOCSET_DEFAULT_SIZES);
-AQO_cache_mem_ctx = AllocSetContextCreate(TopMemoryContext,
-"AQO_cache_mem_ctx",
+/*
+* AQO Cache Memory Context containe environment data.
+*/
+AQOCacheMemCtx = AllocSetContextCreate(AQOTopMemCtx,
+"AQOCacheMemCtx",
 ALLOCSET_DEFAULT_SIZES);
+/*
+* AQOUtilityMemoryContext containe short-lived information which
+* is appeared from having got clause, selectivity arrays and relid lists
+* while calculating hashes. It clean up inside calculated
+* function or immediately after her having completed.
+*/
+AQOUtilityMemCtx = AllocSetContextCreate(AQOTopMemCtx,
+"AQOUtilityMemoryContext",
+ALLOCSET_DEFAULT_SIZES);
+/*
+* AQOPredictMemoryContext save necessary information for making predict of plan nodes
+* and clean up in the execution stage of query.
+*/
+AQOPredictMemCtx = AllocSetContextCreate(AQOTopMemCtx,
+"AQOPredictMemoryContext",
+ALLOCSET_DEFAULT_SIZES);
+/*
+* AQOLearnMemoryContext save necessary information for writing down to AQO knowledge table
+* and clean up after doing this operation.
+*/
+AQOLearnMemCtx = AllocSetContextCreate(AQOTopMemCtx,
+"AQOLearnMemoryContext",
+ALLOCSET_DEFAULT_SIZES);
 RegisterResourceReleaseCallback(aqo_free_callback, NULL);
 RegisterAQOPlanNodeMethods();
 

aqo.h

@@ -221,9 +221,12 @@ extern double log_selectivity_lower_bound;
 extern QueryContextData query_context;
 extern int njoins;
 
-/* Memory context for long-live data */
-extern MemoryContext AQOMemoryContext;
-extern MemoryContext AQO_cache_mem_ctx;
+/* AQO Memory contexts */
+extern MemoryContext AQOTopMemCtx;
+extern MemoryContext AQOCacheMemCtx;
+extern MemoryContext AQOUtilityMemCtx;
+extern MemoryContext AQOPredictMemCtx;
+extern MemoryContext AQOLearnMemCtx;
 
 /* Saved hook values in case of unload */
 extern post_parse_analyze_hook_type prev_post_parse_analyze_hook;

cardinality_estimation.c

@@ -52,7 +52,6 @@ predict_debug_output(List *clauses, List *selectivities,
 
 appendStringInfo(&debug_str, "}, result: %lf", result);
 elog(DEBUG1, "Prediction: %s", debug_str.data);
-pfree(debug_str.data);
 }
 #endif
 
@@ -104,8 +103,6 @@ predict_for_relation(List *clauses, List *selectivities, List *relsigns,
 #ifdef AQO_DEBUG_PRINT
 predict_debug_output(clauses, selectivities, relsigns, *fss, result);
 #endif
-pfree(features);
-OkNNr_free(data);
 
 if (result < 0)
 return -1;

cardinality_hooks.c

@@ -144,20 +144,21 @@ aqo_set_baserel_rows_estimate(PlannerInfo *root, RelOptInfo *rel)
 List *selectivities = NULL;
 List *clauses;
 int fss = 0;
+MemoryContext old_ctx_m;
 
 if (IsQueryDisabled())
 /* Fast path. */
 goto default_estimator;
 
+old_ctx_m = MemoryContextSwitchTo(AQOPredictMemCtx);
+
 if (query_context.use_aqo || query_context.learn_aqo)
 selectivities = get_selectivities(root, rel->baserestrictinfo, 0,
 JOIN_INNER, NULL);
 
 if (!query_context.use_aqo)
 {
-if (query_context.learn_aqo)
-list_free_deep(selectivities);
-
+MemoryContextSwitchTo(old_ctx_m);
 goto default_estimator;
 }
 
@@ -175,10 +176,8 @@ aqo_set_baserel_rows_estimate(PlannerInfo *root, RelOptInfo *rel)
 &fss);
 rel->fss_hash = fss;
 
-list_free(rels.hrels);
-list_free(rels.signatures);
-list_free_deep(selectivities);
-list_free(clauses);
+/* Return to the caller's memory context. */
+MemoryContextSwitchTo(old_ctx_m);
 
 if (predicted >= 0)
 {
@@ -225,14 +224,16 @@ aqo_get_parameterized_baserel_size(PlannerInfo *root,
 int *eclass_hash;
 int current_hash;
 int fss = 0;
+MemoryContext oldctx;
 
 if (IsQueryDisabled())
 /* Fast path */
 goto default_estimator;
 
+oldctx = MemoryContextSwitchTo(AQOPredictMemCtx);
+
 if (query_context.use_aqo || query_context.learn_aqo)
 {
-MemoryContext old_ctx_m;
 
 selectivities = list_concat(
 get_selectivities(root, param_clauses, rel->relid,
@@ -248,8 +249,6 @@ aqo_get_parameterized_baserel_size(PlannerInfo *root,
 rte = planner_rt_fetch(rel->relid, root);
 get_eclasses(allclauses, &nargs, &args_hash, &eclass_hash);
 
-old_ctx_m = MemoryContextSwitchTo(AQO_cache_mem_ctx);
-
 forboth(l, allclauses, l2, selectivities)
 {
 current_hash = get_clause_hash(
@@ -258,19 +257,11 @@ aqo_get_parameterized_baserel_size(PlannerInfo *root,
 cache_selectivity(current_hash, rel->relid, rte->relid,
 *((double *) lfirst(l2)));
 }
-
-MemoryContextSwitchTo(old_ctx_m);
-pfree(args_hash);
-pfree(eclass_hash);
 }
 
 if (!query_context.use_aqo)
 {
-if (query_context.learn_aqo)
-{
-list_free_deep(selectivities);
-list_free(allclauses);
-}
+MemoryContextSwitchTo(oldctx);
 
 goto default_estimator;
 }
@@ -284,8 +275,9 @@ aqo_get_parameterized_baserel_size(PlannerInfo *root,
 }
 
 predicted = predict_for_relation(allclauses, selectivities, rels.signatures, &fss);
-list_free(rels.hrels);
-list_free(rels.signatures);
+
+/* Return to the caller's memory context */
+MemoryContextSwitchTo(oldctx);
 
 predicted_ppi_rows = predicted;
 fss_ppi_hash = fss;
@@ -319,20 +311,20 @@ aqo_set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
 List *outer_selectivities;
 List *current_selectivities = NULL;
 int fss = 0;
+MemoryContext old_ctx_m;
 
 if (IsQueryDisabled())
 /* Fast path */
 goto default_estimator;
 
+old_ctx_m = MemoryContextSwitchTo(AQOPredictMemCtx);
+
 if (query_context.use_aqo || query_context.learn_aqo)
 current_selectivities = get_selectivities(root, restrictlist, 0,
 sjinfo->jointype, sjinfo);
-
 if (!query_context.use_aqo)
 {
-if (query_context.learn_aqo)
-list_free_deep(current_selectivities);
-
+MemoryContextSwitchTo(old_ctx_m);
 goto default_estimator;
 }
 
@@ -349,8 +341,9 @@ aqo_set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
 
 predicted = predict_for_relation(allclauses, selectivities, rels.signatures,
 &fss);
-list_free(rels.hrels);
-list_free(rels.signatures);
+
+/* Return to the caller's memory context */
+MemoryContextSwitchTo(old_ctx_m);
 
 rel->fss_hash = fss;
 
@@ -391,20 +384,21 @@ aqo_get_parameterized_joinrel_size(PlannerInfo *root,
 List *outer_selectivities;
 List *current_selectivities = NULL;
 int fss = 0;
+MemoryContext old_ctx_m;
 
 if (IsQueryDisabled())
 /* Fast path */
 goto default_estimator;
 
+old_ctx_m = MemoryContextSwitchTo(AQOPredictMemCtx);
+
 if (query_context.use_aqo || query_context.learn_aqo)
 current_selectivities = get_selectivities(root, clauses, 0,
 sjinfo->jointype, sjinfo);
 
 if (!query_context.use_aqo)
 {
-if (query_context.learn_aqo)
-list_free_deep(current_selectivities);
-
+MemoryContextSwitchTo(old_ctx_m);
 goto default_estimator;
 }
 
@@ -419,8 +413,8 @@ aqo_get_parameterized_joinrel_size(PlannerInfo *root,
 
 predicted = predict_for_relation(allclauses, selectivities, rels.signatures,
 &fss);
-list_free(rels.hrels);
-list_free(rels.signatures);
+/* Return to the caller's memory context */
+MemoryContextSwitchTo(old_ctx_m);
 
 predicted_ppi_rows = predicted;
 fss_ppi_hash = fss;
@@ -455,8 +449,6 @@ predict_num_groups(PlannerInfo *root, Path *subpath, List *group_exprs,
 clauses = get_path_clauses(subpath, root, &selectivities);
 (void) predict_for_relation(clauses, selectivities, rels.signatures,
 &child_fss);
-list_free(rels.hrels);
-list_free(rels.signatures);
 }
 
 *fss = get_grouped_exprs_hash(child_fss, group_exprs);
@@ -477,6 +469,7 @@ aqo_estimate_num_groups_hook(PlannerInfo *root, List *groupExprs,
 {
 int fss;
 double predicted;
+MemoryContext old_ctx_m;
 
 if (!query_context.use_aqo)
 goto default_estimator;
@@ -495,12 +488,15 @@ aqo_estimate_num_groups_hook(PlannerInfo *root, List *groupExprs,
 if (groupExprs == NIL)
 return 1.0;
 
+old_ctx_m = MemoryContextSwitchTo(AQOPredictMemCtx);
+
 predicted = predict_num_groups(root, subpath, groupExprs, &fss);
 if (predicted > 0.)
 {
 grouped_rel->predicted_cardinality = predicted;
 grouped_rel->rows = predicted;
 grouped_rel->fss_hash = fss;
+MemoryContextSwitchTo(old_ctx_m);
 return predicted;
 }
 else
@@ -510,6 +506,8 @@ aqo_estimate_num_groups_hook(PlannerInfo *root, List *groupExprs,
 */
 grouped_rel->predicted_cardinality = -1;
 
+MemoryContextSwitchTo(old_ctx_m);
+
 default_estimator:
 return default_estimate_num_groups(root, groupExprs, subpath, grouped_rel,
 pgset, estinfo);