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sr_plan.c
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sr_plan.c
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#include "sr_plan.h"
#include "commands/defrem.h"
#include "commands/event_trigger.h"
#include "commands/extension.h"
#include "catalog/pg_extension.h"
#include "catalog/indexing.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "access/hash.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "miscadmin.h"
#if PG_VERSION_NUM >= 100000
#include "utils/queryenvironment.h"
#include "catalog/index.h"
#endif
#if PG_VERSION_NUM >= 120000
#include "catalog/pg_extension_d.h"
#endif
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(do_nothing);
PG_FUNCTION_INFO_V1(show_plan);
void _PG_init(void);
void _PG_fini(void);
static planner_hook_type srplan_planner_hook_next = NULL;
post_parse_analyze_hook_type srplan_post_parse_analyze_hook_next = NULL;
typedef struct SrPlanCachedInfo {
bool enabled;
bool write_mode;
bool explain_query;
int log_usage;
Oid fake_func;
Oid schema_oid;
Oid sr_plans_oid;
Oid sr_index_oid;
Oid reloids_index_oid;
Oid index_reloids_index_oid;
const char *query_text;
} SrPlanCachedInfo;
typedef struct show_plan_funcctx {
ExplainFormat format;
char *output;
int lines_count;
} show_plan_funcctx;
static SrPlanCachedInfo cachedInfo = {
true, /* enabled */
false, /* write_mode */
false, /* explain_query */
0, /* log_usage */
0, /* fake_func */
InvalidOid, /* schema_oid */
InvalidOid, /* sr_plans_reloid */
InvalidOid, /* sr_plans_index_oid */
InvalidOid, /* reloids_index_oid */
InvalidOid, /* index_reloids_index_oid */
NULL
};
static PlannedStmt *sr_planner(Query *parse, int cursorOptions,
ParamListInfo boundParams);
static void sr_analyze(ParseState *pstate, Query *query);
static Oid get_sr_plan_schema(void);
static Oid sr_get_relname_oid(Oid schema_oid, const char *relname);
static bool sr_query_walker(Query *node, void *context);
static bool sr_query_expr_walker(Node *node, void *context);
void walker_callback(void *node);
static void sr_plan_relcache_hook(Datum arg, Oid relid);
static void plan_tree_visitor(Plan *plan,
void (*visitor) (Plan *plan, void *context),
void *context);
static void execute_for_plantree(PlannedStmt *planned_stmt,
void (*proc) (void *context, Plan *plan),
void *context);
static void restore_params(void *context, Plan *plan);
static Datum get_query_hash(Query *node);
static void collect_indexid(void *context, Plan *plan);
struct QueryParam
{
int location;
int funccollid;
void *node;
};
struct QueryParamsContext
{
bool collect;
List *params;
};
struct IndexIds
{
List *ids;
};
List *query_params;
static void
invalidate_oids(void)
{
cachedInfo.schema_oid = InvalidOid;
cachedInfo.sr_plans_oid = InvalidOid;
cachedInfo.sr_index_oid = InvalidOid;
cachedInfo.fake_func = InvalidOid;
cachedInfo.reloids_index_oid = InvalidOid;
cachedInfo.index_reloids_index_oid = InvalidOid;
}
static void
init_sr_plan(void)
{
char *schema_name;
List *func_name_list;
Oid args[1] = {ANYELEMENTOID};
static bool relcache_callback_needed = true;
cachedInfo.schema_oid = get_sr_plan_schema();
if (cachedInfo.schema_oid == InvalidOid)
return;
cachedInfo.sr_index_oid = sr_get_relname_oid(cachedInfo.schema_oid,
SR_PLANS_TABLE_QUERY_INDEX_NAME);
cachedInfo.sr_plans_oid = sr_get_relname_oid(cachedInfo.schema_oid,
SR_PLANS_TABLE_NAME);
cachedInfo.reloids_index_oid = sr_get_relname_oid(cachedInfo.schema_oid,
SR_PLANS_RELOIDS_INDEX);
cachedInfo.index_reloids_index_oid = sr_get_relname_oid(cachedInfo.schema_oid,
SR_PLANS_INDEX_RELOIDS_INDEX);
if (cachedInfo.sr_plans_oid == InvalidOid ||
cachedInfo.sr_index_oid == InvalidOid)
elog(ERROR, "sr_plan extension installed incorrectly");
/* Initialize _p function Oid */
schema_name = get_namespace_name(cachedInfo.schema_oid);
func_name_list = list_make2(makeString(schema_name), makeString("_p"));
cachedInfo.fake_func = LookupFuncName(func_name_list, 1, args, true);
list_free(func_name_list);
pfree(schema_name);
if (cachedInfo.fake_func == InvalidOid)
elog(ERROR, "sr_plan extension installed incorrectly");
if (relcache_callback_needed)
{
CacheRegisterRelcacheCallback(sr_plan_relcache_hook, PointerGetDatum(NULL));
relcache_callback_needed = false;
}
}
/*
* Check if 'stmt' is ALTER EXTENSION sr_plan
*/
static bool
is_alter_extension_cmd(Node *stmt)
{
if (!stmt)
return false;
if (!IsA(stmt, AlterExtensionStmt))
return false;
if (pg_strcasecmp(((AlterExtensionStmt *) stmt)->extname, "sr_plan") == 0)
return true;
return false;
}
static bool
is_drop_extension_stmt(Node *stmt)
{
char *objname;
DropStmt *ds = (DropStmt *) stmt;
if (!stmt)
return false;
if (!IsA(stmt, DropStmt))
return false;
#if PG_VERSION_NUM < 100000
objname = strVal(linitial(linitial(ds->objects)));
#else
objname = strVal(linitial(ds->objects));
#endif
if (ds->removeType == OBJECT_EXTENSION &&
pg_strcasecmp(objname, "sr_plan") == 0)
return true;
return false;
}
static void
sr_plan_relcache_hook(Datum arg, Oid relid)
{
if (relid == InvalidOid || (relid == cachedInfo.sr_plans_oid))
invalidate_oids();
}
/*
* TODO: maybe support for EXPLAIN (cached 1)
static void
check_for_explain_cached(ExplainStmt *stmt)
{
List *reslist;
ListCell *lc;
if (!IsA(stmt, ExplainStmt))
return;
reslist = NIL;
foreach(lc, stmt->options)
{
DefElem *opt = (DefElem *) lfirst(lc);
if (strcmp(opt->defname, "cached") == 0 &&
strcmp(defGetString(opt), "on") == 0)
cachedInfo.explain_query = true;
else
reslist = lappend(reslist, opt);
}
stmt->options = reslist;
}*/
static void
sr_analyze(ParseState *pstate, Query *query)
{
cachedInfo.query_text = pstate->p_sourcetext;
cachedInfo.explain_query = false;
if (query->commandType == CMD_UTILITY)
{
if (IsA(query->utilityStmt, ExplainStmt))
cachedInfo.explain_query = true;
/* ... ALTER EXTENSION sr_plan */
if (is_alter_extension_cmd(query->utilityStmt))
invalidate_oids();
/* ... DROP EXTENSION sr_plan */
if (is_drop_extension_stmt(query->utilityStmt))
{
invalidate_oids();
cachedInfo.enabled = false;
elog(NOTICE, "sr_plan was disabled");
}
}
}
/*
* Return sr_plan schema's Oid or InvalidOid if that's not possible.
*/
static Oid
get_sr_plan_schema(void)
{
Oid result;
Relation rel;
SysScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
Oid ext_schema;
LOCKMODE heap_lock = AccessShareLock;
/* It's impossible to fetch sr_plan's schema now */
if (!IsTransactionState())
return InvalidOid;
ext_schema = get_extension_oid("sr_plan", true);
if (ext_schema == InvalidOid)
return InvalidOid; /* exit if sr_plan does not exist */
#if PG_VERSION_NUM >= 120000
ScanKeyInit(&entry[0],
Anum_pg_extension_oid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(ext_schema));
#else
ScanKeyInit(&entry[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(ext_schema));
#endif
rel = heap_open(ExtensionRelationId, heap_lock);
scandesc = systable_beginscan(rel, ExtensionOidIndexId, true,
NULL, 1, entry);
tuple = systable_getnext(scandesc);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(tuple))
result = ((Form_pg_extension) GETSTRUCT(tuple))->extnamespace;
else
result = InvalidOid;
systable_endscan(scandesc);
heap_close(rel, heap_lock);
return result;
}
/*
* Return Oid of relation in sr_plan extension schema or
* InvalidOid if that's not possible.
*/
static Oid
sr_get_relname_oid(Oid schema_oid, const char *relname)
{
if (schema_oid == InvalidOid)
schema_oid = get_sr_plan_schema();
if (schema_oid == InvalidOid)
return InvalidOid;
return get_relname_relid(relname, schema_oid);
}
static void
params_restore_visitor(Plan *plan, void *context)
{
expression_tree_walker((Node *) plan->qual, sr_query_expr_walker, context);
expression_tree_walker((Node *) plan->targetlist, sr_query_expr_walker, context);
}
static void
restore_params(void *context, Plan *plan)
{
plan_tree_visitor(plan, params_restore_visitor, context);
}
static void
collect_indexid_visitor(Plan *plan, void *context)
{
struct IndexIds *index_ids = context;
if (plan == NULL)
return;
if (IsA(plan, IndexScan))
{
IndexScan *scan = (IndexScan *) plan;
index_ids->ids = lappend_oid(index_ids->ids, scan->indexid);
}
if (IsA(plan, IndexOnlyScan))
{
IndexOnlyScan *scan = (IndexOnlyScan *) plan;
index_ids->ids = lappend_oid(index_ids->ids, scan->indexid);
}
if (IsA(plan, BitmapIndexScan))
{
BitmapIndexScan *scan = (BitmapIndexScan *) plan;
index_ids->ids = lappend_oid(index_ids->ids, scan->indexid);
}
}
static void
collect_indexid(void *context, Plan *plan)
{
plan_tree_visitor(plan, collect_indexid_visitor, context);
}
static PlannedStmt *
lookup_plan_by_query_hash(Snapshot snapshot, Relation sr_index_rel,
Relation sr_plans_heap, ScanKey key,
void *context,
int index,
char **queryString)
{
int counter = 0;
PlannedStmt *pl_stmt = NULL;
HeapTuple htup;
IndexScanDesc query_index_scan;
query_index_scan = index_beginscan(sr_plans_heap, sr_index_rel, snapshot, 1, 0);
index_rescan(query_index_scan, key, 1, NULL, 0);
while ((htup = index_getnext(query_index_scan, ForwardScanDirection)) != NULL)
{
Datum search_values[Anum_sr_attcount];
bool search_nulls[Anum_sr_attcount];
heap_deform_tuple(htup, sr_plans_heap->rd_att,
search_values, search_nulls);
/* Check enabled field or index */
counter++;
if ((index > 0 && index == counter) ||
(index == 0 && DatumGetBool(search_values[Anum_sr_enable - 1])))
{
char *out = TextDatumGetCString(DatumGetTextP((search_values[Anum_sr_plan - 1])));
pl_stmt = stringToNode(out);
if (queryString)
*queryString = TextDatumGetCString(
DatumGetTextP((search_values[Anum_sr_query - 1])));
if (context)
execute_for_plantree(pl_stmt, restore_params, context);
break;
}
}
index_endscan(query_index_scan);
return pl_stmt;
}
static PlannedStmt *
sr_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
{
Datum query_hash;
Relation sr_plans_heap,
sr_index_rel;
HeapTuple tuple;
char *plan_text;
Snapshot snapshot;
ScanKeyData key;
bool found;
Datum plan_hash;
IndexScanDesc query_index_scan;
PlannedStmt *pl_stmt = NULL;
LOCKMODE heap_lock = AccessShareLock;
struct QueryParamsContext qp_context = {true, NULL};
static int level = 0;
level++;
#define call_standard_planner() \
(srplan_planner_hook_next ? \
srplan_planner_hook_next(parse, cursorOptions, boundParams) : \
standard_planner(parse, cursorOptions, boundParams))
/* Only save plans for SELECT commands */
if (parse->commandType != CMD_SELECT || !cachedInfo.enabled
|| cachedInfo.explain_query)
{
pl_stmt = call_standard_planner();
level--;
return pl_stmt;
}
/* Set extension Oid if needed */
if (cachedInfo.schema_oid == InvalidOid)
init_sr_plan();
if (cachedInfo.schema_oid == InvalidOid)
{
/* Just call standard_planner() if schema doesn't exist. */
pl_stmt = call_standard_planner();
level--;
return pl_stmt;
}
/* Make list with all _p functions and his position */
sr_query_walker((Query *) parse, &qp_context);
query_hash = get_query_hash(parse);
ScanKeyInit(&key, 1, BTEqualStrategyNumber, F_INT4EQ, query_hash);
/* Try to find already planned statement */
heap_lock = AccessShareLock;
sr_plans_heap = heap_open(cachedInfo.sr_plans_oid, heap_lock);
sr_index_rel = index_open(cachedInfo.sr_index_oid, heap_lock);
qp_context.collect = false;
snapshot = RegisterSnapshot(GetLatestSnapshot());
pl_stmt = lookup_plan_by_query_hash(snapshot, sr_index_rel, sr_plans_heap,
&key, &qp_context, 0, NULL);
if (pl_stmt != NULL)
{
level--;
if (cachedInfo.log_usage > 0)
elog(cachedInfo.log_usage, "sr_plan: cached plan was used for query: %s", cachedInfo.query_text);
goto cleanup;
}
if (!cachedInfo.write_mode || level > 1)
{
/* quick way out if not in write mode */
pl_stmt = call_standard_planner();
level--;
goto cleanup;
}
/* close and get AccessExclusiveLock */
UnregisterSnapshot(snapshot);
index_close(sr_index_rel, heap_lock);
heap_close(sr_plans_heap, heap_lock);
heap_lock = AccessExclusiveLock;
sr_plans_heap = heap_open(cachedInfo.sr_plans_oid, heap_lock);
sr_index_rel = index_open(cachedInfo.sr_index_oid, heap_lock);
/* recheck plan in index */
snapshot = RegisterSnapshot(GetLatestSnapshot());
pl_stmt = lookup_plan_by_query_hash(snapshot, sr_index_rel, sr_plans_heap,
&key, &qp_context, 0, NULL);
if (pl_stmt != NULL)
{
level--;
goto cleanup;
}
/* from now on we use this new plan */
pl_stmt = call_standard_planner();
level--;
plan_text = nodeToString(pl_stmt);
plan_hash = hash_any((unsigned char *) plan_text, strlen(plan_text));
/*
* Try to find existing plan for this query and skip addding it
* to prevent duplicates.
*/
query_index_scan = index_beginscan(sr_plans_heap, sr_index_rel,
snapshot, 1, 0);
index_rescan(query_index_scan, &key, 1, NULL, 0);
found = false;
for (;;)
{
HeapTuple htup;
Datum search_values[Anum_sr_attcount];
bool search_nulls[Anum_sr_attcount];
ItemPointer tid = index_getnext_tid(query_index_scan, ForwardScanDirection);
if (tid == NULL)
break;
htup = index_fetch_heap(query_index_scan);
heap_deform_tuple(htup, sr_plans_heap->rd_att,
search_values, search_nulls);
/* Detect full plan duplicate */
if (DatumGetInt32(search_values[Anum_sr_plan_hash - 1]) == DatumGetInt32(plan_hash))
{
found = true;
break;
}
}
index_endscan(query_index_scan);
if (!found)
{
struct IndexIds index_ids = {NIL};
Relation reloids_index_rel;
Relation index_reloids_index_rel;
ArrayType *reloids = NULL;
ArrayType *index_reloids = NULL;
Datum values[Anum_sr_attcount];
bool nulls[Anum_sr_attcount];
int reloids_len = list_length(pl_stmt->relationOids);
/* prepare indexes */
reloids_index_rel = index_open(cachedInfo.reloids_index_oid, heap_lock);
index_reloids_index_rel = index_open(cachedInfo.index_reloids_index_oid, heap_lock);
MemSet(nulls, 0, sizeof(nulls));
values[Anum_sr_query_hash - 1] = query_hash;
values[Anum_sr_query_id - 1] = Int64GetDatum(parse->queryId);
values[Anum_sr_plan_hash - 1] = plan_hash;
values[Anum_sr_query - 1] = CStringGetTextDatum(cachedInfo.query_text);
values[Anum_sr_plan - 1] = CStringGetTextDatum(plan_text);
values[Anum_sr_enable - 1] = BoolGetDatum(false);
values[Anum_sr_reloids - 1] = (Datum) 0;
values[Anum_sr_index_reloids - 1] = (Datum) 0;
/* save related oids */
if (reloids_len)
{
int pos;
ListCell *lc;
Datum *reloids_arr = palloc(sizeof(Datum) * reloids_len);
pos = 0;
foreach(lc, pl_stmt->relationOids)
{
reloids_arr[pos] = ObjectIdGetDatum(lfirst_oid(lc));
pos++;
}
reloids = construct_array(reloids_arr, reloids_len, OIDOID,
sizeof(Oid), true, 'i');
values[Anum_sr_reloids - 1] = PointerGetDatum(reloids);
pfree(reloids_arr);
}
else nulls[Anum_sr_reloids - 1] = true;
/* saved related index oids */
execute_for_plantree(pl_stmt, collect_indexid, (void *) &index_ids);
if (list_length(index_ids.ids))
{
int len = list_length(index_ids.ids);
int pos;
ListCell *lc;
Datum *ids_arr = palloc(sizeof(Datum) * len);
pos = 0;
foreach(lc, index_ids.ids)
{
ids_arr[pos] = ObjectIdGetDatum(lfirst_oid(lc));
pos++;
}
index_reloids = construct_array(ids_arr, len, OIDOID,
sizeof(Oid), true, 'i');
values[Anum_sr_index_reloids - 1] = PointerGetDatum(index_reloids);
pfree(ids_arr);
}
else nulls[Anum_sr_index_reloids - 1] = true;
tuple = heap_form_tuple(sr_plans_heap->rd_att, values, nulls);
simple_heap_insert(sr_plans_heap, tuple);
if (cachedInfo.log_usage)
elog(cachedInfo.log_usage, "sr_plan: saved plan for %s", cachedInfo.query_text);
index_insert_compat(sr_index_rel,
values, nulls,
&(tuple->t_self),
sr_plans_heap,
UNIQUE_CHECK_NO);
if (reloids)
{
index_insert_compat(reloids_index_rel,
&values[Anum_sr_reloids - 1],
&nulls[Anum_sr_reloids-1],
&(tuple->t_self),
sr_plans_heap,
UNIQUE_CHECK_NO);
}
if (index_reloids)
{
index_insert_compat(index_reloids_index_rel,
&values[Anum_sr_index_reloids - 1],
&nulls[Anum_sr_index_reloids-1],
&(tuple->t_self),
sr_plans_heap,
UNIQUE_CHECK_NO);
}
index_close(reloids_index_rel, heap_lock);
index_close(index_reloids_index_rel, heap_lock);
/* Make changes visible */
CommandCounterIncrement();
}
cleanup:
UnregisterSnapshot(snapshot);
index_close(sr_index_rel, heap_lock);
heap_close(sr_plans_heap, heap_lock);
return pl_stmt;
}
static bool
sr_query_walker(Query *node, void *context)
{
if (node == NULL)
return false;
// check for nodes that special work is required for, eg:
if (IsA(node, FromExpr))
return sr_query_expr_walker((Node *)node, context);
// for any node type not specially processed, do:
if (IsA(node, Query))
return query_tree_walker(node, sr_query_walker, context, 0);
return false;
}
static bool
sr_query_expr_walker(Node *node, void *context)
{
struct QueryParamsContext *qp_context = context;
FuncExpr *fexpr = (FuncExpr *) node;
if (node == NULL)
return false;
if (IsA(node, FuncExpr) && fexpr->funcid == cachedInfo.fake_func)
{
if (qp_context->collect)
{
struct QueryParam *param = (struct QueryParam *) palloc(sizeof(struct QueryParam));
param->location = fexpr->location;
param->node = fexpr->args->head->data.ptr_value;
param->funccollid = fexpr->funccollid;
/* HACK: location could lost after planning */
fexpr->funccollid = fexpr->location;
if (cachedInfo.log_usage)
elog(cachedInfo.log_usage, "sr_plan: collected parameter on %d", param->location);
qp_context->params = lappend(qp_context->params, param);
}
else
{
ListCell *lc;
foreach(lc, qp_context->params)
{
struct QueryParam *param = lfirst(lc);
if (param->location == fexpr->funccollid)
{
fexpr->funccollid = param->funccollid;
fexpr->args->head->data.ptr_value = param->node;
if (cachedInfo.log_usage)
elog(cachedInfo.log_usage, "sr_plan: restored parameter on %d", param->location);
break;
}
}
}
return false;
}
return expression_tree_walker(node, sr_query_expr_walker, context);
}
static bool
sr_query_fake_const_expr_walker(Node *node, void *context)
{
FuncExpr *fexpr = (FuncExpr *) node;
if (node == NULL)
return false;
if (IsA(node, FuncExpr) && fexpr->funcid == cachedInfo.fake_func)
{
Const *fakeconst;
fakeconst = makeConst(23, -1, 0, 4, (Datum) 0, false, true);
fexpr->args = list_make1(fakeconst);
}
return expression_tree_walker(node, sr_query_fake_const_expr_walker, context);
}
static bool
sr_query_fake_const_walker(Node *node, void *context)
{
if (node == NULL)
return false;
// check for nodes that special work is required for, eg:
if (IsA(node, FromExpr))
return sr_query_fake_const_expr_walker(node, context);
// for any node type not specially processed, do:
if (IsA(node, Query))
{
Query *q = (Query *) node;
return query_tree_walker(q, sr_query_fake_const_walker, context, 0);
}
return false;
}
static Datum
get_query_hash(Query *node)
{
Datum result;
Node *copy;
MemoryContext tmpctx,
oldctx;
char *temp;
tmpctx = AllocSetContextCreate(CurrentMemoryContext,
"temporary context",
ALLOCSET_DEFAULT_SIZES);
oldctx = MemoryContextSwitchTo(tmpctx);
copy = copyObject((Node *) node);
sr_query_fake_const_walker(copy, NULL);
temp = nodeToString(copy);
result = hash_any((unsigned char *) temp, strlen(temp));
MemoryContextSwitchTo(oldctx);
MemoryContextDelete(tmpctx);
return result;
}
static const struct config_enum_entry log_usage_options[] = {
{"none", 0, true},
{"debug", DEBUG2, true},
{"debug5", DEBUG5, false},
{"debug4", DEBUG4, false},
{"debug3", DEBUG3, false},
{"debug2", DEBUG2, false},
{"debug1", DEBUG1, false},
{"log", LOG, false},
{"info", INFO, true},
{"notice", NOTICE, false},
{"warning", WARNING, false},
{NULL, 0, false}
};
void
_PG_init(void)
{
DefineCustomBoolVariable("sr_plan.write_mode",
"Save all plans for all queries.",
NULL,
&cachedInfo.write_mode,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("sr_plan.enabled",
"Enable sr_plan.",
NULL,
&cachedInfo.enabled,
true,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomEnumVariable("sr_plan.log_usage",
"Log cached plan usage with specified level",
NULL,
&cachedInfo.log_usage,
0,
log_usage_options,
PGC_USERSET,
0,
NULL,
NULL,
NULL);
srplan_planner_hook_next = planner_hook;
planner_hook = &sr_planner;
srplan_post_parse_analyze_hook_next = post_parse_analyze_hook;
post_parse_analyze_hook = &sr_analyze;
}
void
_PG_fini(void)
{
/* nothing to do */
}
Datum
do_nothing(PG_FUNCTION_ARGS)
{
PG_RETURN_DATUM(PG_GETARG_DATUM(0));
}
/*
* Construct the result tupledesc for an EXPLAIN
*/
static TupleDesc
make_tupledesc(ExplainState *es)
{
TupleDesc tupdesc;
Oid result_type;
/* Check for XML format option */
switch (es->format)
{
case EXPLAIN_FORMAT_XML:
result_type = XMLOID;
break;
case EXPLAIN_FORMAT_JSON:
result_type = JSONOID;
break;
default:
result_type = TEXTOID;
}
/* Need a tuple descriptor representing a single TEXT or XML column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "QUERY PLAN", result_type, -1, 0);
return tupdesc;
}
Datum
show_plan(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
show_plan_funcctx *ctx;
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcxt;
PlannedStmt *pl_stmt = NULL;
LOCKMODE heap_lock = AccessShareLock;
Relation sr_plans_heap,
sr_index_rel;
Snapshot snapshot;
ScanKeyData key;
char *queryString;
ExplainState *es = NewExplainState();
uint32 index,
query_hash = PG_GETARG_INT32(0);
funcctx = SRF_FIRSTCALL_INIT();
if (!PG_ARGISNULL(1))
index = PG_GETARG_INT32(1); /* show by index or enabled (if 0) */
else
index = 0; /* show enabled one */
es->analyze = false;
es->costs = false;
es->verbose = true;
es->buffers = false;
es->timing = false;
es->summary = false;
es->format = EXPLAIN_FORMAT_TEXT;
if (!PG_ARGISNULL(2))
{
char *p = PG_GETARG_CSTRING(2);
if (strcmp(p, "text") == 0)
es->format = EXPLAIN_FORMAT_TEXT;
else if (strcmp(p, "xml") == 0)
es->format = EXPLAIN_FORMAT_XML;
else if (strcmp(p, "json") == 0)
es->format = EXPLAIN_FORMAT_JSON;
else if (strcmp(p, "yaml") == 0)
es->format = EXPLAIN_FORMAT_YAML;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("unrecognized value for output format \"%s\"", p),
errhint("supported formats: 'text', 'xml', 'json', 'yaml'")));
}
/* Try to find already planned statement */
sr_plans_heap = heap_open(cachedInfo.sr_plans_oid, heap_lock);
sr_index_rel = index_open(cachedInfo.sr_index_oid, heap_lock);
snapshot = RegisterSnapshot(GetLatestSnapshot());
ScanKeyInit(&key, 1, BTEqualStrategyNumber, F_INT4EQ, query_hash);
pl_stmt = lookup_plan_by_query_hash(snapshot, sr_index_rel, sr_plans_heap,
&key, NULL, index, &queryString);
if (pl_stmt == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not find saved plan")));
ExplainBeginOutput(es);
#if PG_VERSION_NUM >= 100000
ExplainOnePlan(pl_stmt, NULL, es, queryString, NULL, NULL, NULL);
#else
ExplainOnePlan(pl_stmt, NULL, es, queryString, NULL, NULL);
#endif
ExplainEndOutput(es);
Assert(es->indent == 0);
UnregisterSnapshot(snapshot);
index_close(sr_index_rel, heap_lock);
heap_close(sr_plans_heap, heap_lock);
oldcxt = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
funcctx->tuple_desc = BlessTupleDesc(make_tupledesc(es));
funcctx->user_fctx = palloc(sizeof(show_plan_funcctx));
ctx = (show_plan_funcctx *) funcctx->user_fctx;