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Move pg_stat_statements query jumbling to core.

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Add compute_query_id GUC to control whether a query identifier should be
computed by the core (off by default).  It's thefore now possible to
disable core queryid computation and use pg_stat_statements with a
different algorithm to compute the query identifier by using a
third-party module.

To ensure that a single source of query identifier can be used and is
well defined, modules that calculate a query identifier should throw an
error if compute_query_id specified to compute a query id and if a query
idenfitier was already calculated.

Discussion: https://postgr.es/m/20210407125726.tkvjdbw76hxnpwfi@nol

Author: Julien Rouhaud

Reviewed-by: Alvaro Herrera, Nitin Jadhav, Zhihong Yu
This commit is contained in:
Bruce Momjian
2021-04-07 13:06:47 -04:00
parent a282ee68a0
commit 5fd9dfa5f5
13 changed files with 995 additions and 785 deletions
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805
contrib/pg_stat_statements/pg_stat_statements.c
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@ -8,24 +8,9 @@
* a shared hashtable. (We track only as many distinct queries as will fit * a shared hashtable. (We track only as many distinct queries as will fit
* in the designated amount of shared memory.) * in the designated amount of shared memory.)
* *
* As of Postgres 9.2, this module normalizes query entries. Normalization * Starting in Postgres 9.2, this module normalized query entries. As of
* is a process whereby similar queries, typically differing only in their * Postgres 14, the normalization is done by the core if compute_query_id is
* constants (though the exact rules are somewhat more subtle than that) are * enabled, or optionally by third-party modules.
* recognized as equivalent, and are tracked as a single entry. This is
* particularly useful for non-prepared queries.
*
* Normalization is implemented by fingerprinting queries, selectively
* serializing those fields of each query tree's nodes that are judged to be
* essential to the query. This is referred to as a query jumble. This is
* distinct from a regular serialization in that various extraneous
* information is ignored as irrelevant or not essential to the query, such
* as the collations of Vars and, most notably, the values of constants.
*
* This jumble is acquired at the end of parse analysis of each query, and
* a 64-bit hash of it is stored into the query's Query.queryId field.
* The server then copies this value around, making it available in plan
* tree(s) generated from the query. The executor can then use this value
* to blame query costs on the proper queryId.
* *
* To facilitate presenting entries to users, we create "representative" query * To facilitate presenting entries to users, we create "representative" query
* strings in which constants are replaced with parameter symbols ($n), to * strings in which constants are replaced with parameter symbols ($n), to
@ -116,8 +101,6 @@ static const uint32 PGSS_PG_MAJOR_VERSION = PG_VERSION_NUM / 100;
#define USAGE_DEALLOC_PERCENT 5 /* free this % of entries at once */ #define USAGE_DEALLOC_PERCENT 5 /* free this % of entries at once */
#define IS_STICKY(c) ((c.calls[PGSS_PLAN] + c.calls[PGSS_EXEC]) == 0) #define IS_STICKY(c) ((c.calls[PGSS_PLAN] + c.calls[PGSS_EXEC]) == 0)
#define JUMBLE_SIZE 1024 /* query serialization buffer size */
/* /*
* Extension version number, for supporting older extension versions' objects * Extension version number, for supporting older extension versions' objects
*/ */
@ -237,40 +220,6 @@ typedef struct pgssSharedState
pgssGlobalStats stats; /* global statistics for pgss */ pgssGlobalStats stats; /* global statistics for pgss */
} pgssSharedState; } pgssSharedState;
/*
* Struct for tracking locations/lengths of constants during normalization
*/
typedef struct pgssLocationLen
{
int location; /* start offset in query text */
int length; /* length in bytes, or -1 to ignore */
} pgssLocationLen;
/*
* Working state for computing a query jumble and producing a normalized
* query string
*/
typedef struct pgssJumbleState
{
/* Jumble of current query tree */
unsigned char *jumble;
/* Number of bytes used in jumble[] */
Size jumble_len;
/* Array of locations of constants that should be removed */
pgssLocationLen *clocations;
/* Allocated length of clocations array */
int clocations_buf_size;
/* Current number of valid entries in clocations array */
int clocations_count;
/* highest Param id we've seen, in order to start normalization correctly */
int highest_extern_param_id;
} pgssJumbleState;
/*---- Local variables ----*/ /*---- Local variables ----*/
/* Current nesting depth of ExecutorRun+ProcessUtility calls */ /* Current nesting depth of ExecutorRun+ProcessUtility calls */
@ -344,7 +293,8 @@ PG_FUNCTION_INFO_V1(pg_stat_statements_info);
static void pgss_shmem_startup(void); static void pgss_shmem_startup(void);
static void pgss_shmem_shutdown(int code, Datum arg); static void pgss_shmem_shutdown(int code, Datum arg);
static void pgss_post_parse_analyze(ParseState *pstate, Query *query); static void pgss_post_parse_analyze(ParseState *pstate, Query *query,
JumbleState *jstate);
static PlannedStmt *pgss_planner(Query *parse, static PlannedStmt *pgss_planner(Query *parse,
const char *query_string, const char *query_string,
int cursorOptions, int cursorOptions,
@ -366,7 +316,7 @@ static void pgss_store(const char *query, uint64 queryId,
double total_time, uint64 rows, double total_time, uint64 rows,
const BufferUsage *bufusage, const BufferUsage *bufusage,
const WalUsage *walusage, const WalUsage *walusage,
pgssJumbleState *jstate); JumbleState *jstate);
static void pg_stat_statements_internal(FunctionCallInfo fcinfo, static void pg_stat_statements_internal(FunctionCallInfo fcinfo,
pgssVersion api_version, pgssVersion api_version,
bool showtext); bool showtext);
@ -382,16 +332,9 @@ static char *qtext_fetch(Size query_offset, int query_len,
static bool need_gc_qtexts(void); static bool need_gc_qtexts(void);
static void gc_qtexts(void); static void gc_qtexts(void);
static void entry_reset(Oid userid, Oid dbid, uint64 queryid); static void entry_reset(Oid userid, Oid dbid, uint64 queryid);
static void AppendJumble(pgssJumbleState *jstate, static char *generate_normalized_query(JumbleState *jstate, const char *query,
const unsigned char *item, Size size);
static void JumbleQuery(pgssJumbleState *jstate, Query *query);
static void JumbleRangeTable(pgssJumbleState *jstate, List *rtable);
static void JumbleRowMarks(pgssJumbleState *jstate, List *rowMarks);
static void JumbleExpr(pgssJumbleState *jstate, Node *node);
static void RecordConstLocation(pgssJumbleState *jstate, int location);
static char *generate_normalized_query(pgssJumbleState *jstate, const char *query,
int query_loc, int *query_len_p); int query_loc, int *query_len_p);
static void fill_in_constant_lengths(pgssJumbleState *jstate, const char *query, static void fill_in_constant_lengths(JumbleState *jstate, const char *query,
int query_loc); int query_loc);
static int comp_location(const void *a, const void *b); static int comp_location(const void *a, const void *b);
@ -853,15 +796,10 @@ error:
* Post-parse-analysis hook: mark query with a queryId * Post-parse-analysis hook: mark query with a queryId
*/ */
static void static void
pgss_post_parse_analyze(ParseState *pstate, Query *query) pgss_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
{ {
pgssJumbleState jstate;
if (prev_post_parse_analyze_hook) if (prev_post_parse_analyze_hook)
prev_post_parse_analyze_hook(pstate, query); prev_post_parse_analyze_hook(pstate, query, jstate);
/* Assert we didn't do this already */
Assert(query->queryId == UINT64CONST(0));
/* Safety check... */ /* Safety check... */
if (!pgss || !pgss_hash || !pgss_enabled(exec_nested_level)) if (!pgss || !pgss_hash || !pgss_enabled(exec_nested_level))
@ -881,35 +819,14 @@ pgss_post_parse_analyze(ParseState *pstate, Query *query)
return; return;
} }
/* Set up workspace for query jumbling */
jstate.jumble = (unsigned char *) palloc(JUMBLE_SIZE);
jstate.jumble_len = 0;
jstate.clocations_buf_size = 32;
jstate.clocations = (pgssLocationLen *)
palloc(jstate.clocations_buf_size * sizeof(pgssLocationLen));
jstate.clocations_count = 0;
jstate.highest_extern_param_id = 0;
/* Compute query ID and mark the Query node with it */
JumbleQuery(&jstate, query);
query->queryId =
DatumGetUInt64(hash_any_extended(jstate.jumble, jstate.jumble_len, 0));
/* /*
* If we are unlucky enough to get a hash of zero, use 1 instead, to * If query jumbling were able to identify any ignorable constants, we
* prevent confusion with the utility-statement case. * immediately create a hash table entry for the query, so that we can
* record the normalized form of the query string. If there were no such
* constants, the normalized string would be the same as the query text
* anyway, so there's no need for an early entry.
*/ */
if (query->queryId == UINT64CONST(0)) if (jstate && jstate->clocations_count > 0)
query->queryId = UINT64CONST(1);
/*
* If we were able to identify any ignorable constants, we immediately
* create a hash table entry for the query, so that we can record the
* normalized form of the query string. If there were no such constants,
* the normalized string would be the same as the query text anyway, so
* there's no need for an early entry.
*/
if (jstate.clocations_count > 0)
pgss_store(pstate->p_sourcetext, pgss_store(pstate->p_sourcetext,
query->queryId, query->queryId,
query->stmt_location, query->stmt_location,
@ -919,7 +836,7 @@ pgss_post_parse_analyze(ParseState *pstate, Query *query)
0, 0,
NULL, NULL,
NULL, NULL,
&jstate); jstate);
} }
/* /*
@ -1269,7 +1186,7 @@ pgss_store(const char *query, uint64 queryId,
double total_time, uint64 rows, double total_time, uint64 rows,
const BufferUsage *bufusage, const BufferUsage *bufusage,
const WalUsage *walusage, const WalUsage *walusage,
pgssJumbleState *jstate) JumbleState *jstate)
{ {
pgssHashKey key; pgssHashKey key;
pgssEntry *entry; pgssEntry *entry;
@ -2629,678 +2546,6 @@ release_lock:
LWLockRelease(pgss->lock); LWLockRelease(pgss->lock);
} }
/*
* AppendJumble: Append a value that is substantive in a given query to
* the current jumble.
*/
static void
AppendJumble(pgssJumbleState *jstate, const unsigned char *item, Size size)
{
unsigned char *jumble = jstate->jumble;
Size jumble_len = jstate->jumble_len;
/*
* Whenever the jumble buffer is full, we hash the current contents and
* reset the buffer to contain just that hash value, thus relying on the
* hash to summarize everything so far.
*/
while (size > 0)
{
Size part_size;
if (jumble_len >= JUMBLE_SIZE)
{
uint64 start_hash;
start_hash = DatumGetUInt64(hash_any_extended(jumble,
JUMBLE_SIZE, 0));
memcpy(jumble, &start_hash, sizeof(start_hash));
jumble_len = sizeof(start_hash);
}
part_size = Min(size, JUMBLE_SIZE - jumble_len);
memcpy(jumble + jumble_len, item, part_size);
jumble_len += part_size;
item += part_size;
size -= part_size;
}
jstate->jumble_len = jumble_len;
}
/*
* Wrappers around AppendJumble to encapsulate details of serialization
* of individual local variable elements.
*/
#define APP_JUMB(item) \
AppendJumble(jstate, (const unsigned char *) &(item), sizeof(item))
#define APP_JUMB_STRING(str) \
AppendJumble(jstate, (const unsigned char *) (str), strlen(str) + 1)
/*
* JumbleQuery: Selectively serialize the query tree, appending significant
* data to the "query jumble" while ignoring nonsignificant data.
*
* Rule of thumb for what to include is that we should ignore anything not
* semantically significant (such as alias names) as well as anything that can
* be deduced from child nodes (else we'd just be double-hashing that piece
* of information).
*/
static void
JumbleQuery(pgssJumbleState *jstate, Query *query)
{
Assert(IsA(query, Query));
Assert(query->utilityStmt == NULL);
APP_JUMB(query->commandType);
/* resultRelation is usually predictable from commandType */
JumbleExpr(jstate, (Node *) query->cteList);
JumbleRangeTable(jstate, query->rtable);
JumbleExpr(jstate, (Node *) query->jointree);
JumbleExpr(jstate, (Node *) query->targetList);
JumbleExpr(jstate, (Node *) query->onConflict);
JumbleExpr(jstate, (Node *) query->returningList);
JumbleExpr(jstate, (Node *) query->groupClause);
JumbleExpr(jstate, (Node *) query->groupingSets);
JumbleExpr(jstate, query->havingQual);
JumbleExpr(jstate, (Node *) query->windowClause);
JumbleExpr(jstate, (Node *) query->distinctClause);
JumbleExpr(jstate, (Node *) query->sortClause);
JumbleExpr(jstate, query->limitOffset);
JumbleExpr(jstate, query->limitCount);
JumbleRowMarks(jstate, query->rowMarks);
JumbleExpr(jstate, query->setOperations);
}
/*
* Jumble a range table
*/
static void
JumbleRangeTable(pgssJumbleState *jstate, List *rtable)
{
ListCell *lc;
foreach(lc, rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc);
APP_JUMB(rte->rtekind);
switch (rte->rtekind)
{
case RTE_RELATION:
APP_JUMB(rte->relid);
JumbleExpr(jstate, (Node *) rte->tablesample);
break;
case RTE_SUBQUERY:
JumbleQuery(jstate, rte->subquery);
break;
case RTE_JOIN:
APP_JUMB(rte->jointype);
break;
case RTE_FUNCTION:
JumbleExpr(jstate, (Node *) rte->functions);
break;
case RTE_TABLEFUNC:
JumbleExpr(jstate, (Node *) rte->tablefunc);
break;
case RTE_VALUES:
JumbleExpr(jstate, (Node *) rte->values_lists);
break;
case RTE_CTE:
/*
* Depending on the CTE name here isn't ideal, but it's the
* only info we have to identify the referenced WITH item.
*/
APP_JUMB_STRING(rte->ctename);
APP_JUMB(rte->ctelevelsup);
break;
case RTE_NAMEDTUPLESTORE:
APP_JUMB_STRING(rte->enrname);
break;
case RTE_RESULT:
break;
default:
elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
break;
}
}
}
/*
* Jumble a rowMarks list
*/
static void
JumbleRowMarks(pgssJumbleState *jstate, List *rowMarks)
{
ListCell *lc;
foreach(lc, rowMarks)
{
RowMarkClause *rowmark = lfirst_node(RowMarkClause, lc);
if (!rowmark->pushedDown)
{
APP_JUMB(rowmark->rti);
APP_JUMB(rowmark->strength);
APP_JUMB(rowmark->waitPolicy);
}
}
}
/*
* Jumble an expression tree
*
* In general this function should handle all the same node types that
* expression_tree_walker() does, and therefore it's coded to be as parallel
* to that function as possible. However, since we are only invoked on
* queries immediately post-parse-analysis, we need not handle node types
* that only appear in planning.
*
* Note: the reason we don't simply use expression_tree_walker() is that the
* point of that function is to support tree walkers that don't care about
* most tree node types, but here we care about all types. We should complain
* about any unrecognized node type.
*/
static void
JumbleExpr(pgssJumbleState *jstate, Node *node)
{
ListCell *temp;
if (node == NULL)
return;
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
/*
* We always emit the node's NodeTag, then any additional fields that are
* considered significant, and then we recurse to any child nodes.
*/
APP_JUMB(node->type);
switch (nodeTag(node))
{
case T_Var:
{
Var *var = (Var *) node;
APP_JUMB(var->varno);
APP_JUMB(var->varattno);
APP_JUMB(var->varlevelsup);
}
break;
case T_Const:
{
Const *c = (Const *) node;
/* We jumble only the constant's type, not its value */
APP_JUMB(c->consttype);
/* Also, record its parse location for query normalization */
RecordConstLocation(jstate, c->location);
}
break;
case T_Param:
{
Param *p = (Param *) node;
APP_JUMB(p->paramkind);
APP_JUMB(p->paramid);
APP_JUMB(p->paramtype);
/* Also, track the highest external Param id */
if (p->paramkind == PARAM_EXTERN &&
p->paramid > jstate->highest_extern_param_id)
jstate->highest_extern_param_id = p->paramid;
}
break;
case T_Aggref:
{
Aggref *expr = (Aggref *) node;
APP_JUMB(expr->aggfnoid);
JumbleExpr(jstate, (Node *) expr->aggdirectargs);
JumbleExpr(jstate, (Node *) expr->args);
JumbleExpr(jstate, (Node *) expr->aggorder);
JumbleExpr(jstate, (Node *) expr->aggdistinct);
JumbleExpr(jstate, (Node *) expr->aggfilter);
}
break;
case T_GroupingFunc:
{
GroupingFunc *grpnode = (GroupingFunc *) node;
JumbleExpr(jstate, (Node *) grpnode->refs);
}
break;
case T_WindowFunc:
{
WindowFunc *expr = (WindowFunc *) node;
APP_JUMB(expr->winfnoid);
APP_JUMB(expr->winref);
JumbleExpr(jstate, (Node *) expr->args);
JumbleExpr(jstate, (Node *) expr->aggfilter);
}
break;
case T_SubscriptingRef:
{
SubscriptingRef *sbsref = (SubscriptingRef *) node;
JumbleExpr(jstate, (Node *) sbsref->refupperindexpr);
JumbleExpr(jstate, (Node *) sbsref->reflowerindexpr);
JumbleExpr(jstate, (Node *) sbsref->refexpr);
JumbleExpr(jstate, (Node *) sbsref->refassgnexpr);
}
break;
case T_FuncExpr:
{
FuncExpr *expr = (FuncExpr *) node;
APP_JUMB(expr->funcid);
JumbleExpr(jstate, (Node *) expr->args);
}
break;
case T_NamedArgExpr:
{
NamedArgExpr *nae = (NamedArgExpr *) node;
APP_JUMB(nae->argnumber);
JumbleExpr(jstate, (Node *) nae->arg);
}
break;
case T_OpExpr:
case T_DistinctExpr: /* struct-equivalent to OpExpr */
case T_NullIfExpr: /* struct-equivalent to OpExpr */
{
OpExpr *expr = (OpExpr *) node;
APP_JUMB(expr->opno);
JumbleExpr(jstate, (Node *) expr->args);
}
break;
case T_ScalarArrayOpExpr:
{
ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) node;
APP_JUMB(expr->opno);
APP_JUMB(expr->useOr);
JumbleExpr(jstate, (Node *) expr->args);
}
break;
case T_BoolExpr:
{
BoolExpr *expr = (BoolExpr *) node;
APP_JUMB(expr->boolop);
JumbleExpr(jstate, (Node *) expr->args);
}
break;
case T_SubLink:
{
SubLink *sublink = (SubLink *) node;
APP_JUMB(sublink->subLinkType);
APP_JUMB(sublink->subLinkId);
JumbleExpr(jstate, (Node *) sublink->testexpr);
JumbleQuery(jstate, castNode(Query, sublink->subselect));
}
break;
case T_FieldSelect:
{
FieldSelect *fs = (FieldSelect *) node;
APP_JUMB(fs->fieldnum);
JumbleExpr(jstate, (Node *) fs->arg);
}
break;
case T_FieldStore:
{
FieldStore *fstore = (FieldStore *) node;
JumbleExpr(jstate, (Node *) fstore->arg);
JumbleExpr(jstate, (Node *) fstore->newvals);
}
break;
case T_RelabelType:
{
RelabelType *rt = (RelabelType *) node;
APP_JUMB(rt->resulttype);
JumbleExpr(jstate, (Node *) rt->arg);
}
break;
case T_CoerceViaIO:
{
CoerceViaIO *cio = (CoerceViaIO *) node;
APP_JUMB(cio->resulttype);
JumbleExpr(jstate, (Node *) cio->arg);
}
break;
case T_ArrayCoerceExpr:
{
ArrayCoerceExpr *acexpr = (ArrayCoerceExpr *) node;
APP_JUMB(acexpr->resulttype);
JumbleExpr(jstate, (Node *) acexpr->arg);
JumbleExpr(jstate, (Node *) acexpr->elemexpr);
}
break;
case T_ConvertRowtypeExpr:
{
ConvertRowtypeExpr *crexpr = (ConvertRowtypeExpr *) node;
APP_JUMB(crexpr->resulttype);
JumbleExpr(jstate, (Node *) crexpr->arg);
}
break;
case T_CollateExpr:
{
CollateExpr *ce = (CollateExpr *) node;
APP_JUMB(ce->collOid);
JumbleExpr(jstate, (Node *) ce->arg);
}
break;
case T_CaseExpr:
{
CaseExpr *caseexpr = (CaseExpr *) node;
JumbleExpr(jstate, (Node *) caseexpr->arg);
foreach(temp, caseexpr->args)
{
CaseWhen *when = lfirst_node(CaseWhen, temp);
JumbleExpr(jstate, (Node *) when->expr);
JumbleExpr(jstate, (Node *) when->result);
}
JumbleExpr(jstate, (Node *) caseexpr->defresult);
}
break;
case T_CaseTestExpr:
{
CaseTestExpr *ct = (CaseTestExpr *) node;
APP_JUMB(ct->typeId);
}
break;
case T_ArrayExpr:
JumbleExpr(jstate, (Node *) ((ArrayExpr *) node)->elements);
break;
case T_RowExpr:
JumbleExpr(jstate, (Node *) ((RowExpr *) node)->args);
break;
case T_RowCompareExpr:
{
RowCompareExpr *rcexpr = (RowCompareExpr *) node;
APP_JUMB(rcexpr->rctype);
JumbleExpr(jstate, (Node *) rcexpr->largs);
JumbleExpr(jstate, (Node *) rcexpr->rargs);
}
break;
case T_CoalesceExpr:
JumbleExpr(jstate, (Node *) ((CoalesceExpr *) node)->args);
break;
case T_MinMaxExpr:
{
MinMaxExpr *mmexpr = (MinMaxExpr *) node;
APP_JUMB(mmexpr->op);
JumbleExpr(jstate, (Node *) mmexpr->args);
}
break;
case T_SQLValueFunction:
{
SQLValueFunction *svf = (SQLValueFunction *) node;
APP_JUMB(svf->op);
/* type is fully determined by op */
APP_JUMB(svf->typmod);
}
break;
case T_XmlExpr:
{
XmlExpr *xexpr = (XmlExpr *) node;
APP_JUMB(xexpr->op);
JumbleExpr(jstate, (Node *) xexpr->named_args);
JumbleExpr(jstate, (Node *) xexpr->args);
}
break;
case T_NullTest:
{
NullTest *nt = (NullTest *) node;
APP_JUMB(nt->nulltesttype);
JumbleExpr(jstate, (Node *) nt->arg);
}
break;
case T_BooleanTest:
{
BooleanTest *bt = (BooleanTest *) node;
APP_JUMB(bt->booltesttype);
JumbleExpr(jstate, (Node *) bt->arg);
}
break;
case T_CoerceToDomain:
{
CoerceToDomain *cd = (CoerceToDomain *) node;
APP_JUMB(cd->resulttype);
JumbleExpr(jstate, (Node *) cd->arg);
}
break;
case T_CoerceToDomainValue:
{
CoerceToDomainValue *cdv = (CoerceToDomainValue *) node;
APP_JUMB(cdv->typeId);
}
break;
case T_SetToDefault:
{
SetToDefault *sd = (SetToDefault *) node;
APP_JUMB(sd->typeId);
}
break;
case T_CurrentOfExpr:
{
CurrentOfExpr *ce = (CurrentOfExpr *) node;
APP_JUMB(ce->cvarno);
if (ce->cursor_name)
APP_JUMB_STRING(ce->cursor_name);
APP_JUMB(ce->cursor_param);
}
break;
case T_NextValueExpr:
{
NextValueExpr *nve = (NextValueExpr *) node;
APP_JUMB(nve->seqid);
APP_JUMB(nve->typeId);
}
break;
case T_InferenceElem:
{
InferenceElem *ie = (InferenceElem *) node;
APP_JUMB(ie->infercollid);
APP_JUMB(ie->inferopclass);
JumbleExpr(jstate, ie->expr);
}
break;
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *) node;
APP_JUMB(tle->resno);
APP_JUMB(tle->ressortgroupref);
JumbleExpr(jstate, (Node *) tle->expr);
}
break;
case T_RangeTblRef:
{
RangeTblRef *rtr = (RangeTblRef *) node;
APP_JUMB(rtr->rtindex);
}
break;
case T_JoinExpr:
{
JoinExpr *join = (JoinExpr *) node;
APP_JUMB(join->jointype);
APP_JUMB(join->isNatural);
APP_JUMB(join->rtindex);
JumbleExpr(jstate, join->larg);
JumbleExpr(jstate, join->rarg);
JumbleExpr(jstate, join->quals);
}
break;
case T_FromExpr:
{
FromExpr *from = (FromExpr *) node;
JumbleExpr(jstate, (Node *) from->fromlist);
JumbleExpr(jstate, from->quals);
}
break;
case T_OnConflictExpr:
{
OnConflictExpr *conf = (OnConflictExpr *) node;
APP_JUMB(conf->action);
JumbleExpr(jstate, (Node *) conf->arbiterElems);
JumbleExpr(jstate, conf->arbiterWhere);
JumbleExpr(jstate, (Node *) conf->onConflictSet);
JumbleExpr(jstate, conf->onConflictWhere);
APP_JUMB(conf->constraint);
APP_JUMB(conf->exclRelIndex);
JumbleExpr(jstate, (Node *) conf->exclRelTlist);
}
break;
case T_List:
foreach(temp, (List *) node)
{
JumbleExpr(jstate, (Node *) lfirst(temp));
}
break;
case T_IntList:
foreach(temp, (List *) node)
{
APP_JUMB(lfirst_int(temp));
}
break;
case T_SortGroupClause:
{
SortGroupClause *sgc = (SortGroupClause *) node;
APP_JUMB(sgc->tleSortGroupRef);
APP_JUMB(sgc->eqop);
APP_JUMB(sgc->sortop);
APP_JUMB(sgc->nulls_first);
}
break;
case T_GroupingSet:
{
GroupingSet *gsnode = (GroupingSet *) node;
JumbleExpr(jstate, (Node *) gsnode->content);
}
break;
case T_WindowClause:
{
WindowClause *wc = (WindowClause *) node;
APP_JUMB(wc->winref);
APP_JUMB(wc->frameOptions);
JumbleExpr(jstate, (Node *) wc->partitionClause);
JumbleExpr(jstate, (Node *) wc->orderClause);
JumbleExpr(jstate, wc->startOffset);
JumbleExpr(jstate, wc->endOffset);
}
break;
case T_CommonTableExpr:
{
CommonTableExpr *cte = (CommonTableExpr *) node;
/* we store the string name because RTE_CTE RTEs need it */
APP_JUMB_STRING(cte->ctename);
APP_JUMB(cte->ctematerialized);
JumbleQuery(jstate, castNode(Query, cte->ctequery));
}
break;
case T_SetOperationStmt:
{
SetOperationStmt *setop = (SetOperationStmt *) node;
APP_JUMB(setop->op);
APP_JUMB(setop->all);
JumbleExpr(jstate, setop->larg);
JumbleExpr(jstate, setop->rarg);
}
break;
case T_RangeTblFunction:
{
RangeTblFunction *rtfunc = (RangeTblFunction *) node;
JumbleExpr(jstate, rtfunc->funcexpr);
}
break;
case T_TableFunc:
{
TableFunc *tablefunc = (TableFunc *) node;
JumbleExpr(jstate, tablefunc->docexpr);
JumbleExpr(jstate, tablefunc->rowexpr);
JumbleExpr(jstate, (Node *) tablefunc->colexprs);
}
break;
case T_TableSampleClause:
{
TableSampleClause *tsc = (TableSampleClause *) node;
APP_JUMB(tsc->tsmhandler);
JumbleExpr(jstate, (Node *) tsc->args);
JumbleExpr(jstate, (Node *) tsc->repeatable);
}
break;
default:
/* Only a warning, since we can stumble along anyway */
elog(WARNING, "unrecognized node type: %d",
(int) nodeTag(node));
break;
}
}
/*
* Record location of constant within query string of query tree
* that is currently being walked.
*/
static void
RecordConstLocation(pgssJumbleState *jstate, int location)
{
/* -1 indicates unknown or undefined location */
if (location >= 0)
{
/* enlarge array if needed */
if (jstate->clocations_count >= jstate->clocations_buf_size)
{
jstate->clocations_buf_size *= 2;
jstate->clocations = (pgssLocationLen *)
repalloc(jstate->clocations,
jstate->clocations_buf_size *
sizeof(pgssLocationLen));
}
jstate->clocations[jstate->clocations_count].location = location;
/* initialize lengths to -1 to simplify fill_in_constant_lengths */
jstate->clocations[jstate->clocations_count].length = -1;
jstate->clocations_count++;
}
}
/* /*
* Generate a normalized version of the query string that will be used to * Generate a normalized version of the query string that will be used to
* represent all similar queries. * represent all similar queries.
@ -3321,7 +2566,7 @@ RecordConstLocation(pgssJumbleState *jstate, int location)
* Returns a palloc'd string. * Returns a palloc'd string.
*/ */
static char * static char *
generate_normalized_query(pgssJumbleState *jstate, const char *query, generate_normalized_query(JumbleState *jstate, const char *query,
int query_loc, int *query_len_p) int query_loc, int *query_len_p)
{ {
char *norm_query; char *norm_query;
@ -3428,10 +2673,10 @@ generate_normalized_query(pgssJumbleState *jstate, const char *query,
* reason for a constant to start with a '-'. * reason for a constant to start with a '-'.
*/ */
static void static void
fill_in_constant_lengths(pgssJumbleState *jstate, const char *query, fill_in_constant_lengths(JumbleState *jstate, const char *query,
int query_loc) int query_loc)
{ {
pgssLocationLen *locs; LocationLen *locs;
core_yyscan_t yyscanner; core_yyscan_t yyscanner;
core_yy_extra_type yyextra; core_yy_extra_type yyextra;
core_YYSTYPE yylval; core_YYSTYPE yylval;
@ -3445,7 +2690,7 @@ fill_in_constant_lengths(pgssJumbleState *jstate, const char *query,
*/ */
if (jstate->clocations_count > 1) if (jstate->clocations_count > 1)
qsort(jstate->clocations, jstate->clocations_count, qsort(jstate->clocations, jstate->clocations_count,
sizeof(pgssLocationLen), comp_location); sizeof(LocationLen), comp_location);
locs = jstate->clocations; locs = jstate->clocations;
/* initialize the flex scanner --- should match raw_parser() */ /* initialize the flex scanner --- should match raw_parser() */
@ -3525,13 +2770,13 @@ fill_in_constant_lengths(pgssJumbleState *jstate, const char *query,
} }
/* /*
* comp_location: comparator for qsorting pgssLocationLen structs by location * comp_location: comparator for qsorting LocationLen structs by location
*/ */
static int static int
comp_location(const void *a, const void *b) comp_location(const void *a, const void *b)
{ {
int l = ((const pgssLocationLen *) a)->location; int l = ((const LocationLen *) a)->location;
int r = ((const pgssLocationLen *) b)->location; int r = ((const LocationLen *) b)->location;
if (l < r) if (l < r)
return -1; return -1;

1
contrib/pg_stat_statements/pg_stat_statements.conf
View File

@ -1 +1,2 @@
shared_preload_libraries = 'pg_stat_statements' shared_preload_libraries = 'pg_stat_statements'
compute_query_id = on

25
doc/src/sgml/config.sgml
View File

@ -7622,6 +7622,31 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
<title>Statistics Monitoring</title> <title>Statistics Monitoring</title>
<variablelist> <variablelist>
<varlistentry id="guc-compute-query-id" xreflabel="compute_query_id">
<term><varname>compute_query_id</varname> (<type>boolean</type>)
<indexterm>
<primary><varname>compute_query_id</varname> configuration parameter</primary>
</indexterm>
</term>
<listitem>
<para>
Enables in-core computation of a query identifier. The <xref
linkend="pgstatstatements"/> extension requires a query identifier
to be computed. Note that an external module can alternatively
be used if the in-core query identifier computation method
isn't acceptable. In this case, in-core computation should
remain disabled. The default is <literal>off</literal>.
</para>
<note>
<para>
To ensure that a only one query identifier is calculated and
displayed, extensions that calculate query identifiers should
throw an error if a query identifier has already been computed.
</para>
</note>
</listitem>
</varlistentry>
<varlistentry> <varlistentry>
<term><varname>log_statement_stats</varname> (<type>boolean</type>) <term><varname>log_statement_stats</varname> (<type>boolean</type>)
<indexterm> <indexterm>

20
doc/src/sgml/pgstatstatements.sgml
View File

@ -20,6 +20,14 @@
This means that a server restart is needed to add or remove the module. This means that a server restart is needed to add or remove the module.
</para> </para>
<para>
The module will not track statistics unless query
identifiers are calculated. This can be done by enabling <xref
linkend="guc-compute-query-id"/> or using a third-party module that
computes its own query identifiers. Note that all statistics tracked
by this module must be reset if the query identifier method is changed.
</para>
<para> <para>
When <filename>pg_stat_statements</filename> is loaded, it tracks When <filename>pg_stat_statements</filename> is loaded, it tracks
statistics across all databases of the server. To access and manipulate statistics across all databases of the server. To access and manipulate
@ -84,7 +92,7 @@
<structfield>queryid</structfield> <type>bigint</type> <structfield>queryid</structfield> <type>bigint</type>
</para> </para>
<para> <para>
Internal hash code, computed from the statement's parse tree Hash code to identify identical normalized queries.
</para></entry> </para></entry>
</row> </row>
@ -386,6 +394,16 @@
are compared strictly on the basis of their textual query strings, however. are compared strictly on the basis of their textual query strings, however.
</para> </para>
<note>
<para>
The following details about constant replacement and
<structfield>queryid</structfield> only applies when <xref
linkend="guc-compute-query-id"/> is enabled. If you use an external
module instead to compute <structfield>queryid</structfield>, you
should refer to its documentation for details.
</para>
</note>
<para> <para>
When a constant's value has been ignored for purposes of matching the query When a constant's value has been ignored for purposes of matching the query
to other queries, the constant is replaced by a parameter symbol, such to other queries, the constant is replaced by a parameter symbol, such

14
src/backend/parser/analyze.c
View File

@ -46,6 +46,8 @@
#include "parser/parsetree.h" #include "parser/parsetree.h"
#include "rewrite/rewriteManip.h" #include "rewrite/rewriteManip.h"
#include "utils/builtins.h" #include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/queryjumble.h"
#include "utils/rel.h" #include "utils/rel.h"
@ -107,6 +109,7 @@ parse_analyze(RawStmt *parseTree, const char *sourceText,
{ {
ParseState *pstate = make_parsestate(NULL); ParseState *pstate = make_parsestate(NULL);
Query *query; Query *query;
JumbleState *jstate = NULL;
Assert(sourceText != NULL); /* required as of 8.4 */ Assert(sourceText != NULL); /* required as of 8.4 */
@ -119,8 +122,11 @@ parse_analyze(RawStmt *parseTree, const char *sourceText,
query = transformTopLevelStmt(pstate, parseTree); query = transformTopLevelStmt(pstate, parseTree);
if (compute_query_id)
jstate = JumbleQuery(query, sourceText);
if (post_parse_analyze_hook) if (post_parse_analyze_hook)
(*post_parse_analyze_hook) (pstate, query); (*post_parse_analyze_hook) (pstate, query, jstate);
free_parsestate(pstate); free_parsestate(pstate);
@ -140,6 +146,7 @@ parse_analyze_varparams(RawStmt *parseTree, const char *sourceText,
{ {
ParseState *pstate = make_parsestate(NULL); ParseState *pstate = make_parsestate(NULL);
Query *query; Query *query;
JumbleState *jstate = NULL;
Assert(sourceText != NULL); /* required as of 8.4 */ Assert(sourceText != NULL); /* required as of 8.4 */
@ -152,8 +159,11 @@ parse_analyze_varparams(RawStmt *parseTree, const char *sourceText,
/* make sure all is well with parameter types */ /* make sure all is well with parameter types */
check_variable_parameters(pstate, query); check_variable_parameters(pstate, query);
if (compute_query_id)
jstate = JumbleQuery(query, sourceText);
if (post_parse_analyze_hook) if (post_parse_analyze_hook)
(*post_parse_analyze_hook) (pstate, query); (*post_parse_analyze_hook) (pstate, query, jstate);
free_parsestate(pstate); free_parsestate(pstate);

6
src/backend/tcop/postgres.c
View File

@ -668,6 +668,7 @@ pg_analyze_and_rewrite_params(RawStmt *parsetree,
ParseState *pstate; ParseState *pstate;
Query *query; Query *query;
List *querytree_list; List *querytree_list;
JumbleState *jstate = NULL;
Assert(query_string != NULL); /* required as of 8.4 */ Assert(query_string != NULL); /* required as of 8.4 */
@ -686,8 +687,11 @@ pg_analyze_and_rewrite_params(RawStmt *parsetree,
query = transformTopLevelStmt(pstate, parsetree); query = transformTopLevelStmt(pstate, parsetree);
if (compute_query_id)
jstate = JumbleQuery(query, query_string);
if (post_parse_analyze_hook) if (post_parse_analyze_hook)
(*post_parse_analyze_hook) (pstate, query); (*post_parse_analyze_hook) (pstate, query, jstate);
free_parsestate(pstate); free_parsestate(pstate);

1
src/backend/utils/misc/Makefile
View File

@ -22,6 +22,7 @@ OBJS = \
pg_rusage.o \ pg_rusage.o \
ps_status.o \ ps_status.o \
queryenvironment.o \ queryenvironment.o \
queryjumble.o \
rls.o \ rls.o \
sampling.o \ sampling.o \
superuser.o \ superuser.o \

10
src/backend/utils/misc/guc.c
View File

@ -534,6 +534,7 @@ extern const struct config_enum_entry dynamic_shared_memory_options[];
/* /*
* GUC option variables that are exported from this module * GUC option variables that are exported from this module
*/ */
bool compute_query_id = false;
bool log_duration = false; bool log_duration = false;
bool Debug_print_plan = false; bool Debug_print_plan = false;
bool Debug_print_parse = false; bool Debug_print_parse = false;
@ -1458,6 +1459,15 @@ static struct config_bool ConfigureNamesBool[] =
true, true,
NULL, NULL, NULL NULL, NULL, NULL
}, },
{
{"compute_query_id", PGC_SUSET, STATS_MONITORING,
gettext_noop("Compute query identifiers."),
NULL
},
&compute_query_id,
false,
NULL, NULL, NULL
},
{ {
{"log_parser_stats", PGC_SUSET, STATS_MONITORING, {"log_parser_stats", PGC_SUSET, STATS_MONITORING,
gettext_noop("Writes parser performance statistics to the server log."), gettext_noop("Writes parser performance statistics to the server log."),

1
src/backend/utils/misc/postgresql.conf.sample
View File

@ -596,6 +596,7 @@
# - Monitoring - # - Monitoring -
#compute_query_id = off
#log_parser_stats = off #log_parser_stats = off
#log_planner_stats = off #log_planner_stats = off
#log_executor_stats = off #log_executor_stats = off

834
src/backend/utils/misc/queryjumble.c Normal file
View File

@ -0,0 +1,834 @@
/*-------------------------------------------------------------------------
*
* queryjumble.c
* Query normalization and fingerprinting.
*
* Normalization is a process whereby similar queries, typically differing only
* in their constants (though the exact rules are somewhat more subtle than
* that) are recognized as equivalent, and are tracked as a single entry. This
* is particularly useful for non-prepared queries.
*
* Normalization is implemented by fingerprinting queries, selectively
* serializing those fields of each query tree's nodes that are judged to be
* essential to the query. This is referred to as a query jumble. This is
* distinct from a regular serialization in that various extraneous
* information is ignored as irrelevant or not essential to the query, such
* as the collations of Vars and, most notably, the values of constants.
*
* This jumble is acquired at the end of parse analysis of each query, and
* a 64-bit hash of it is stored into the query's Query.queryId field.
* The server then copies this value around, making it available in plan
* tree(s) generated from the query. The executor can then use this value
* to blame query costs on the proper queryId.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/utils/misc/queryjumble.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "common/hashfn.h"
#include "miscadmin.h"
#include "parser/scansup.h"
#include "utils/queryjumble.h"
#define JUMBLE_SIZE 1024 /* query serialization buffer size */
static uint64 compute_utility_queryid(const char *str, int query_len);
static void AppendJumble(JumbleState *jstate,
const unsigned char *item, Size size);
static void JumbleQueryInternal(JumbleState *jstate, Query *query);
static void JumbleRangeTable(JumbleState *jstate, List *rtable);
static void JumbleRowMarks(JumbleState *jstate, List *rowMarks);
static void JumbleExpr(JumbleState *jstate, Node *node);
static void RecordConstLocation(JumbleState *jstate, int location);
/*
* Given a possibly multi-statement source string, confine our attention to the
* relevant part of the string.
*/
const char *
CleanQuerytext(const char *query, int *location, int *len)
{
int query_location = *location;
int query_len = *len;
/* First apply starting offset, unless it's -1 (unknown). */
if (query_location >= 0)
{
Assert(query_location <= strlen(query));
query += query_location;
/* Length of 0 (or -1) means "rest of string" */
if (query_len <= 0)
query_len = strlen(query);
else
Assert(query_len <= strlen(query));
}
else
{
/* If query location is unknown, distrust query_len as well */
query_location = 0;
query_len = strlen(query);
}
/*
* Discard leading and trailing whitespace, too. Use scanner_isspace()
* not libc's isspace(), because we want to match the lexer's behavior.
*/
while (query_len > 0 && scanner_isspace(query[0]))
query++, query_location++, query_len--;
while (query_len > 0 && scanner_isspace(query[query_len - 1]))
query_len--;
*location = query_location;
*len = query_len;
return query;
}
JumbleState *
JumbleQuery(Query *query, const char *querytext)
{
JumbleState *jstate = NULL;
if (query->utilityStmt)
{
const char *sql;
int query_location = query->stmt_location;
int query_len = query->stmt_len;
/*
* Confine our attention to the relevant part of the string, if the
* query is a portion of a multi-statement source string.
*/
sql = CleanQuerytext(querytext, &query_location, &query_len);
query->queryId = compute_utility_queryid(sql, query_len);
}
else
{
jstate = (JumbleState *) palloc(sizeof(JumbleState));
/* Set up workspace for query jumbling */
jstate->jumble = (unsigned char *) palloc(JUMBLE_SIZE);
jstate->jumble_len = 0;
jstate->clocations_buf_size = 32;
jstate->clocations = (LocationLen *)
palloc(jstate->clocations_buf_size * sizeof(LocationLen));
jstate->clocations_count = 0;
jstate->highest_extern_param_id = 0;
/* Compute query ID and mark the Query node with it */
JumbleQueryInternal(jstate, query);
query->queryId = DatumGetUInt64(hash_any_extended(jstate->jumble,
jstate->jumble_len,
0));
/*
* If we are unlucky enough to get a hash of zero, use 1 instead, to
* prevent confusion with the utility-statement case.
*/
if (query->queryId == UINT64CONST(0))
query->queryId = UINT64CONST(1);
}
return jstate;
}
/*
* Compute a query identifier for the given utility query string.
*/
static uint64
compute_utility_queryid(const char *str, int query_len)
{
uint64 queryId;
queryId = DatumGetUInt64(hash_any_extended((const unsigned char *) str,
query_len, 0));
/*
* If we are unlucky enough to get a hash of zero(invalid), use
* queryID as 2 instead, queryID 1 is already in use for normal
* statements.
*/
if (queryId == UINT64CONST(0))
queryId = UINT64CONST(2);
return queryId;
}
/*
* AppendJumble: Append a value that is substantive in a given query to
* the current jumble.
*/
static void
AppendJumble(JumbleState *jstate, const unsigned char *item, Size size)
{
unsigned char *jumble = jstate->jumble;
Size jumble_len = jstate->jumble_len;
/*
* Whenever the jumble buffer is full, we hash the current contents and
* reset the buffer to contain just that hash value, thus relying on the
* hash to summarize everything so far.
*/
while (size > 0)
{
Size part_size;
if (jumble_len >= JUMBLE_SIZE)
{
uint64 start_hash;
start_hash = DatumGetUInt64(hash_any_extended(jumble,
JUMBLE_SIZE, 0));
memcpy(jumble, &start_hash, sizeof(start_hash));
jumble_len = sizeof(start_hash);
}
part_size = Min(size, JUMBLE_SIZE - jumble_len);
memcpy(jumble + jumble_len, item, part_size);
jumble_len += part_size;
item += part_size;
size -= part_size;
}
jstate->jumble_len = jumble_len;
}
/*
* Wrappers around AppendJumble to encapsulate details of serialization
* of individual local variable elements.
*/
#define APP_JUMB(item) \
AppendJumble(jstate, (const unsigned char *) &(item), sizeof(item))
#define APP_JUMB_STRING(str) \
AppendJumble(jstate, (const unsigned char *) (str), strlen(str) + 1)
/*
* JumbleQueryInternal: Selectively serialize the query tree, appending
* significant data to the "query jumble" while ignoring nonsignificant data.
*
* Rule of thumb for what to include is that we should ignore anything not
* semantically significant (such as alias names) as well as anything that can
* be deduced from child nodes (else we'd just be double-hashing that piece
* of information).
*/
static void
JumbleQueryInternal(JumbleState *jstate, Query *query)
{
Assert(IsA(query, Query));
Assert(query->utilityStmt == NULL);
APP_JUMB(query->commandType);
/* resultRelation is usually predictable from commandType */
JumbleExpr(jstate, (Node *) query->cteList);
JumbleRangeTable(jstate, query->rtable);
JumbleExpr(jstate, (Node *) query->jointree);
JumbleExpr(jstate, (Node *) query->targetList);
JumbleExpr(jstate, (Node *) query->onConflict);
JumbleExpr(jstate, (Node *) query->returningList);
JumbleExpr(jstate, (Node *) query->groupClause);
JumbleExpr(jstate, (Node *) query->groupingSets);
JumbleExpr(jstate, query->havingQual);
JumbleExpr(jstate, (Node *) query->windowClause);
JumbleExpr(jstate, (Node *) query->distinctClause);
JumbleExpr(jstate, (Node *) query->sortClause);
JumbleExpr(jstate, query->limitOffset);
JumbleExpr(jstate, query->limitCount);
JumbleRowMarks(jstate, query->rowMarks);
JumbleExpr(jstate, query->setOperations);
}
/*
* Jumble a range table
*/
static void
JumbleRangeTable(JumbleState *jstate, List *rtable)
{
ListCell *lc;
foreach(lc, rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc);
APP_JUMB(rte->rtekind);
switch (rte->rtekind)
{
case RTE_RELATION:
APP_JUMB(rte->relid);
JumbleExpr(jstate, (Node *) rte->tablesample);
break;
case RTE_SUBQUERY:
JumbleQueryInternal(jstate, rte->subquery);
break;
case RTE_JOIN:
APP_JUMB(rte->jointype);
break;
case RTE_FUNCTION:
JumbleExpr(jstate, (Node *) rte->functions);
break;
case RTE_TABLEFUNC:
JumbleExpr(jstate, (Node *) rte->tablefunc);
break;
case RTE_VALUES:
JumbleExpr(jstate, (Node *) rte->values_lists);
break;
case RTE_CTE:
/*
* Depending on the CTE name here isn't ideal, but it's the
* only info we have to identify the referenced WITH item.
*/
APP_JUMB_STRING(rte->ctename);
APP_JUMB(rte->ctelevelsup);
break;
case RTE_NAMEDTUPLESTORE:
APP_JUMB_STRING(rte->enrname);
break;
case RTE_RESULT:
break;
default:
elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
break;
}
}
}
/*
* Jumble a rowMarks list
*/
static void
JumbleRowMarks(JumbleState *jstate, List *rowMarks)
{
ListCell *lc;
foreach(lc, rowMarks)
{
RowMarkClause *rowmark = lfirst_node(RowMarkClause, lc);
if (!rowmark->pushedDown)
{
APP_JUMB(rowmark->rti);
APP_JUMB(rowmark->strength);
APP_JUMB(rowmark->waitPolicy);
}
}
}
/*
* Jumble an expression tree
*
* In general this function should handle all the same node types that
* expression_tree_walker() does, and therefore it's coded to be as parallel
* to that function as possible. However, since we are only invoked on
* queries immediately post-parse-analysis, we need not handle node types
* that only appear in planning.
*
* Note: the reason we don't simply use expression_tree_walker() is that the
* point of that function is to support tree walkers that don't care about
* most tree node types, but here we care about all types. We should complain
* about any unrecognized node type.
*/
static void
JumbleExpr(JumbleState *jstate, Node *node)
{
ListCell *temp;
if (node == NULL)
return;
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
/*
* We always emit the node's NodeTag, then any additional fields that are
* considered significant, and then we recurse to any child nodes.
*/
APP_JUMB(node->type);
switch (nodeTag(node))
{
case T_Var:
{
Var *var = (Var *) node;
APP_JUMB(var->varno);
APP_JUMB(var->varattno);
APP_JUMB(var->varlevelsup);
}
break;
case T_Const:
{
Const *c = (Const *) node;
/* We jumble only the constant's type, not its value */
APP_JUMB(c->consttype);
/* Also, record its parse location for query normalization */
RecordConstLocation(jstate, c->location);
}
break;
case T_Param:
{
Param *p = (Param *) node;
APP_JUMB(p->paramkind);
APP_JUMB(p->paramid);
APP_JUMB(p->paramtype);
/* Also, track the highest external Param id */
if (p->paramkind == PARAM_EXTERN &&
p->paramid > jstate->highest_extern_param_id)
jstate->highest_extern_param_id = p->paramid;
}
break;
case T_Aggref:
{
Aggref *expr = (Aggref *) node;
APP_JUMB(expr->aggfnoid);
JumbleExpr(jstate, (Node *) expr->aggdirectargs);
JumbleExpr(jstate, (Node *) expr->args);
JumbleExpr(jstate, (Node *) expr->aggorder);
JumbleExpr(jstate, (Node *) expr->aggdistinct);
JumbleExpr(jstate, (Node *) expr->aggfilter);
}
break;
case T_GroupingFunc:
{
GroupingFunc *grpnode = (GroupingFunc *) node;
JumbleExpr(jstate, (Node *) grpnode->refs);
}
break;
case T_WindowFunc:
{
WindowFunc *expr = (WindowFunc *) node;
APP_JUMB(expr->winfnoid);
APP_JUMB(expr->winref);
JumbleExpr(jstate, (Node *) expr->args);
JumbleExpr(jstate, (Node *) expr->aggfilter);
}
break;
case T_SubscriptingRef:
{
SubscriptingRef *sbsref = (SubscriptingRef *) node;
JumbleExpr(jstate, (Node *) sbsref->refupperindexpr);
JumbleExpr(jstate, (Node *) sbsref->reflowerindexpr);
JumbleExpr(jstate, (Node *) sbsref->refexpr);
JumbleExpr(jstate, (Node *) sbsref->refassgnexpr);
}
break;
case T_FuncExpr:
{
FuncExpr *expr = (FuncExpr *) node;
APP_JUMB(expr->funcid);
JumbleExpr(jstate, (Node *) expr->args);
}
break;
case T_NamedArgExpr:
{
NamedArgExpr *nae = (NamedArgExpr *) node;
APP_JUMB(nae->argnumber);
JumbleExpr(jstate, (Node *) nae->arg);
}
break;
case T_OpExpr:
case T_DistinctExpr: /* struct-equivalent to OpExpr */
case T_NullIfExpr: /* struct-equivalent to OpExpr */
{
OpExpr *expr = (OpExpr *) node;
APP_JUMB(expr->opno);
JumbleExpr(jstate, (Node *) expr->args);
}
break;
case T_ScalarArrayOpExpr:
{
ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) node;
APP_JUMB(expr->opno);
APP_JUMB(expr->useOr);
JumbleExpr(jstate, (Node *) expr->args);
}
break;
case T_BoolExpr:
{
BoolExpr *expr = (BoolExpr *) node;
APP_JUMB(expr->boolop);
JumbleExpr(jstate, (Node *) expr->args);
}
break;
case T_SubLink:
{
SubLink *sublink = (SubLink *) node;
APP_JUMB(sublink->subLinkType);
APP_JUMB(sublink->subLinkId);
JumbleExpr(jstate, (Node *) sublink->testexpr);
JumbleQueryInternal(jstate, castNode(Query, sublink->subselect));
}
break;
case T_FieldSelect:
{
FieldSelect *fs = (FieldSelect *) node;
APP_JUMB(fs->fieldnum);
JumbleExpr(jstate, (Node *) fs->arg);
}
break;
case T_FieldStore:
{
FieldStore *fstore = (FieldStore *) node;
JumbleExpr(jstate, (Node *) fstore->arg);
JumbleExpr(jstate, (Node *) fstore->newvals);
}
break;
case T_RelabelType:
{
RelabelType *rt = (RelabelType *) node;
APP_JUMB(rt->resulttype);
JumbleExpr(jstate, (Node *) rt->arg);
}
break;
case T_CoerceViaIO:
{
CoerceViaIO *cio = (CoerceViaIO *) node;
APP_JUMB(cio->resulttype);
JumbleExpr(jstate, (Node *) cio->arg);
}
break;
case T_ArrayCoerceExpr:
{
ArrayCoerceExpr *acexpr = (ArrayCoerceExpr *) node;
APP_JUMB(acexpr->resulttype);
JumbleExpr(jstate, (Node *) acexpr->arg);
JumbleExpr(jstate, (Node *) acexpr->elemexpr);
}
break;
case T_ConvertRowtypeExpr:
{
ConvertRowtypeExpr *crexpr = (ConvertRowtypeExpr *) node;
APP_JUMB(crexpr->resulttype);
JumbleExpr(jstate, (Node *) crexpr->arg);
}
break;
case T_CollateExpr:
{
CollateExpr *ce = (CollateExpr *) node;
APP_JUMB(ce->collOid);
JumbleExpr(jstate, (Node *) ce->arg);
}
break;
case T_CaseExpr:
{
CaseExpr *caseexpr = (CaseExpr *) node;
JumbleExpr(jstate, (Node *) caseexpr->arg);
foreach(temp, caseexpr->args)
{
CaseWhen *when = lfirst_node(CaseWhen, temp);
JumbleExpr(jstate, (Node *) when->expr);
JumbleExpr(jstate, (Node *) when->result);
}
JumbleExpr(jstate, (Node *) caseexpr->defresult);
}
break;
case T_CaseTestExpr:
{
CaseTestExpr *ct = (CaseTestExpr *) node;
APP_JUMB(ct->typeId);
}
break;
case T_ArrayExpr:
JumbleExpr(jstate, (Node *) ((ArrayExpr *) node)->elements);
break;
case T_RowExpr:
JumbleExpr(jstate, (Node *) ((RowExpr *) node)->args);
break;
case T_RowCompareExpr:
{
RowCompareExpr *rcexpr = (RowCompareExpr *) node;
APP_JUMB(rcexpr->rctype);
JumbleExpr(jstate, (Node *) rcexpr->largs);
JumbleExpr(jstate, (Node *) rcexpr->rargs);
}
break;
case T_CoalesceExpr:
JumbleExpr(jstate, (Node *) ((CoalesceExpr *) node)->args);
break;
case T_MinMaxExpr:
{
MinMaxExpr *mmexpr = (MinMaxExpr *) node;
APP_JUMB(mmexpr->op);
JumbleExpr(jstate, (Node *) mmexpr->args);
}
break;
case T_SQLValueFunction:
{
SQLValueFunction *svf = (SQLValueFunction *) node;
APP_JUMB(svf->op);
/* type is fully determined by op */
APP_JUMB(svf->typmod);
}
break;
case T_XmlExpr:
{
XmlExpr *xexpr = (XmlExpr *) node;
APP_JUMB(xexpr->op);
JumbleExpr(jstate, (Node *) xexpr->named_args);
JumbleExpr(jstate, (Node *) xexpr->args);
}
break;
case T_NullTest:
{
NullTest *nt = (NullTest *) node;
APP_JUMB(nt->nulltesttype);
JumbleExpr(jstate, (Node *) nt->arg);
}
break;
case T_BooleanTest:
{
BooleanTest *bt = (BooleanTest *) node;
APP_JUMB(bt->booltesttype);
JumbleExpr(jstate, (Node *) bt->arg);
}
break;
case T_CoerceToDomain:
{
CoerceToDomain *cd = (CoerceToDomain *) node;
APP_JUMB(cd->resulttype);
JumbleExpr(jstate, (Node *) cd->arg);
}
break;
case T_CoerceToDomainValue:
{
CoerceToDomainValue *cdv = (CoerceToDomainValue *) node;
APP_JUMB(cdv->typeId);
}
break;
case T_SetToDefault:
{
SetToDefault *sd = (SetToDefault *) node;
APP_JUMB(sd->typeId);
}
break;
case T_CurrentOfExpr:
{
CurrentOfExpr *ce = (CurrentOfExpr *) node;
APP_JUMB(ce->cvarno);
if (ce->cursor_name)
APP_JUMB_STRING(ce->cursor_name);
APP_JUMB(ce->cursor_param);
}
break;
case T_NextValueExpr:
{
NextValueExpr *nve = (NextValueExpr *) node;
APP_JUMB(nve->seqid);
APP_JUMB(nve->typeId);
}
break;
case T_InferenceElem:
{
InferenceElem *ie = (InferenceElem *) node;
APP_JUMB(ie->infercollid);
APP_JUMB(ie->inferopclass);
JumbleExpr(jstate, ie->expr);
}
break;
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *) node;
APP_JUMB(tle->resno);
APP_JUMB(tle->ressortgroupref);
JumbleExpr(jstate, (Node *) tle->expr);
}
break;
case T_RangeTblRef:
{
RangeTblRef *rtr = (RangeTblRef *) node;
APP_JUMB(rtr->rtindex);
}
break;
case T_JoinExpr:
{
JoinExpr *join = (JoinExpr *) node;
APP_JUMB(join->jointype);
APP_JUMB(join->isNatural);
APP_JUMB(join->rtindex);
JumbleExpr(jstate, join->larg);
JumbleExpr(jstate, join->rarg);
JumbleExpr(jstate, join->quals);
}
break;
case T_FromExpr:
{
FromExpr *from = (FromExpr *) node;
JumbleExpr(jstate, (Node *) from->fromlist);
JumbleExpr(jstate, from->quals);
}
break;
case T_OnConflictExpr:
{
OnConflictExpr *conf = (OnConflictExpr *) node;
APP_JUMB(conf->action);
JumbleExpr(jstate, (Node *) conf->arbiterElems);
JumbleExpr(jstate, conf->arbiterWhere);
JumbleExpr(jstate, (Node *) conf->onConflictSet);
JumbleExpr(jstate, conf->onConflictWhere);
APP_JUMB(conf->constraint);
APP_JUMB(conf->exclRelIndex);
JumbleExpr(jstate, (Node *) conf->exclRelTlist);
}
break;
case T_List:
foreach(temp, (List *) node)
{
JumbleExpr(jstate, (Node *) lfirst(temp));
}
break;
case T_IntList:
foreach(temp, (List *) node)
{
APP_JUMB(lfirst_int(temp));
}
break;
case T_SortGroupClause:
{
SortGroupClause *sgc = (SortGroupClause *) node;
APP_JUMB(sgc->tleSortGroupRef);
APP_JUMB(sgc->eqop);
APP_JUMB(sgc->sortop);
APP_JUMB(sgc->nulls_first);
}
break;
case T_GroupingSet:
{
GroupingSet *gsnode = (GroupingSet *) node;
JumbleExpr(jstate, (Node *) gsnode->content);
}
break;
case T_WindowClause:
{
WindowClause *wc = (WindowClause *) node;
APP_JUMB(wc->winref);
APP_JUMB(wc->frameOptions);
JumbleExpr(jstate, (Node *) wc->partitionClause);
JumbleExpr(jstate, (Node *) wc->orderClause);
JumbleExpr(jstate, wc->startOffset);
JumbleExpr(jstate, wc->endOffset);
}
break;
case T_CommonTableExpr:
{
CommonTableExpr *cte = (CommonTableExpr *) node;
/* we store the string name because RTE_CTE RTEs need it */
APP_JUMB_STRING(cte->ctename);
APP_JUMB(cte->ctematerialized);
JumbleQueryInternal(jstate, castNode(Query, cte->ctequery));
}
break;
case T_SetOperationStmt:
{
SetOperationStmt *setop = (SetOperationStmt *) node;
APP_JUMB(setop->op);
APP_JUMB(setop->all);
JumbleExpr(jstate, setop->larg);
JumbleExpr(jstate, setop->rarg);
}
break;
case T_RangeTblFunction:
{
RangeTblFunction *rtfunc = (RangeTblFunction *) node;
JumbleExpr(jstate, rtfunc->funcexpr);
}
break;
case T_TableFunc:
{
TableFunc *tablefunc = (TableFunc *) node;
JumbleExpr(jstate, tablefunc->docexpr);
JumbleExpr(jstate, tablefunc->rowexpr);
JumbleExpr(jstate, (Node *) tablefunc->colexprs);
}
break;
case T_TableSampleClause:
{
TableSampleClause *tsc = (TableSampleClause *) node;
APP_JUMB(tsc->tsmhandler);
JumbleExpr(jstate, (Node *) tsc->args);
JumbleExpr(jstate, (Node *) tsc->repeatable);
}
break;
default:
/* Only a warning, since we can stumble along anyway */
elog(WARNING, "unrecognized node type: %d",
(int) nodeTag(node));
break;
}
}
/*
* Record location of constant within query string of query tree
* that is currently being walked.
*/
static void
RecordConstLocation(JumbleState *jstate, int location)
{
/* -1 indicates unknown or undefined location */
if (location >= 0)
{
/* enlarge array if needed */
if (jstate->clocations_count >= jstate->clocations_buf_size)
{
jstate->clocations_buf_size *= 2;
jstate->clocations = (LocationLen *)
repalloc(jstate->clocations,
jstate->clocations_buf_size *
sizeof(LocationLen));
}
jstate->clocations[jstate->clocations_count].location = location;
/* initialize lengths to -1 to simplify third-party module usage */
jstate->clocations[jstate->clocations_count].length = -1;
jstate->clocations_count++;
}
}

4
src/include/parser/analyze.h
View File

@ -15,10 +15,12 @@
#define ANALYZE_H #define ANALYZE_H
#include "parser/parse_node.h" #include "parser/parse_node.h"
#include "utils/queryjumble.h"
/* Hook for plugins to get control at end of parse analysis */ /* Hook for plugins to get control at end of parse analysis */
typedef void (*post_parse_analyze_hook_type) (ParseState *pstate, typedef void (*post_parse_analyze_hook_type) (ParseState *pstate,
Query *query); Query *query,
JumbleState *jstate);
extern PGDLLIMPORT post_parse_analyze_hook_type post_parse_analyze_hook; extern PGDLLIMPORT post_parse_analyze_hook_type post_parse_analyze_hook;

1
src/include/utils/guc.h
View File

@ -248,6 +248,7 @@ extern bool log_btree_build_stats;
extern PGDLLIMPORT bool check_function_bodies; extern PGDLLIMPORT bool check_function_bodies;
extern bool session_auth_is_superuser; extern bool session_auth_is_superuser;
extern bool compute_query_id;
extern bool log_duration; extern bool log_duration;
extern int log_parameter_max_length; extern int log_parameter_max_length;
extern int log_parameter_max_length_on_error; extern int log_parameter_max_length_on_error;

58
src/include/utils/queryjumble.h Normal file
View File

@ -0,0 +1,58 @@
/*-------------------------------------------------------------------------
*
* queryjumble.h
* Query normalization and fingerprinting.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/include/utils/queryjumble.h
*
*-------------------------------------------------------------------------
*/
#ifndef QUERYJUBLE_H
#define QUERYJUBLE_H
#include "nodes/parsenodes.h"
#define JUMBLE_SIZE 1024 /* query serialization buffer size */
/*
* Struct for tracking locations/lengths of constants during normalization
*/
typedef struct LocationLen
{
int location; /* start offset in query text */
int length; /* length in bytes, or -1 to ignore */
} LocationLen;
/*
* Working state for computing a query jumble and producing a normalized
* query string
*/
typedef struct JumbleState
{
/* Jumble of current query tree */
unsigned char *jumble;
/* Number of bytes used in jumble[] */
Size jumble_len;
/* Array of locations of constants that should be removed */
LocationLen *clocations;
/* Allocated length of clocations array */
int clocations_buf_size;
/* Current number of valid entries in clocations array */
int clocations_count;
/* highest Param id we've seen, in order to start normalization correctly */
int highest_extern_param_id;
} JumbleState;
const char *CleanQuerytext(const char *query, int *location, int *len);
JumbleState *JumbleQuery(Query *query, const char *querytext);
#endif /* QUERYJUMBLE_H */