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Fix incorrect logic for hashed IN / NOT IN with non-strict operators
ExecEvalHashedScalarArrayOp(), when using a strict equality function, performs a short-circuit when looking up NULL values. When the function is non-strict, the code incorrectly looked up the hash table for a zero-valued Datum, which could have resulted in an accidental true return if the hash table contained zero valued Datum, or could result in a crash for non-byval types. Here we fix this by adding an extra step when we build the hash table to check what the result of a NULL lookup would be. This requires looping over the array and checking what the non-hashed version of the code would do. We cache the results of that in the expression so that we can reuse the result any time we're asked to search for a NULL value. It's important to note that non-strict equality functions are free to treat any NULL value as equal to any non-NULL value. For example, someone may wish to design a type that treats an empty string and NULL as equal. All built-in types have strict equality functions, so this could affect custom / user-defined types. Author: Chengpeng Yan <chengpeng_yan@outlook.com> Author: David Rowley <dgrowleyml@gmail.com> Reviewed-by: ChangAo Chen <cca5507@qq.com> Discussion: https://postgr.es/m/A16187AE-2359-4265-9F5E-71D015EC2B2D@outlook.com Backpatch-through: 14
This commit is contained in:
David Rowley
parent
d7241c156d
commit
622f8b5301
4 changed files with 365 additions and 63 deletions
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@ -167,6 +167,14 @@ static Datum ExecJustAssignOuterVarVirt(ExprState *state, ExprContext *econtext,
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static Datum ExecJustAssignScanVarVirt(ExprState *state, ExprContext *econtext, bool *isnull);
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/* execution helper functions */
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static pg_attribute_always_inline void ExecEvalArrayCompareInternal(FunctionCallInfo fcinfo,
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ArrayType *arr,
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int16 typlen,
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bool typbyval,
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char typalign,
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bool useOr,
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Datum *result,
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bool *resultnull);
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static pg_attribute_always_inline void ExecAggPlainTransByVal(AggState *aggstate,
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AggStatePerTrans pertrans,
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AggStatePerGroup pergroup,
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@ -3319,12 +3327,6 @@ ExecEvalScalarArrayOp(ExprState *state, ExprEvalStep *op)
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int nitems;
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Datum result;
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bool resultnull;
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int16 typlen;
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bool typbyval;
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char typalign;
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char *s;
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bits8 *bitmap;
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int bitmask;
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/*
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* If the array is NULL then we return NULL --- it's not very meaningful
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@ -3373,13 +3375,42 @@ ExecEvalScalarArrayOp(ExprState *state, ExprEvalStep *op)
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op->d.scalararrayop.element_type = ARR_ELEMTYPE(arr);
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}
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typlen = op->d.scalararrayop.typlen;
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typbyval = op->d.scalararrayop.typbyval;
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typalign = op->d.scalararrayop.typalign;
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ExecEvalArrayCompareInternal(fcinfo,
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arr,
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op->d.scalararrayop.typlen,
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op->d.scalararrayop.typbyval,
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op->d.scalararrayop.typalign,
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useOr,
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&result,
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&resultnull);
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*op->resvalue = result;
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*op->resnull = resultnull;
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}
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/*
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* Shared helper for ExecEvalScalarArrayOp() and the NULL-LHS fallback for
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* non-strict ExecEvalHashedScalarArrayOp().
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*
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* Callers must handle the strict LHS-is-NULL; return NULL fast path prior to
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* calling this.
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*/
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static pg_attribute_always_inline void
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ExecEvalArrayCompareInternal(FunctionCallInfo fcinfo, ArrayType *arr,
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int16 typlen, bool typbyval, char typalign,
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bool useOr, Datum *result, bool *resultnull)
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{
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int nitems;
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char *s;
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bits8 *bitmap;
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int bitmask;
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bool strictfunc = fcinfo->flinfo->fn_strict;
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nitems = ArrayGetNItems(ARR_NDIM(arr), ARR_DIMS(arr));
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/* Initialize result appropriately depending on useOr */
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result = BoolGetDatum(!useOr);
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resultnull = false;
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*result = BoolGetDatum(!useOr);
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*resultnull = false;
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/* Loop over the array elements */
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s = (char *) ARR_DATA_PTR(arr);
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@ -3415,18 +3446,18 @@ ExecEvalScalarArrayOp(ExprState *state, ExprEvalStep *op)
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else
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{
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fcinfo->isnull = false;
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thisresult = op->d.scalararrayop.fn_addr(fcinfo);
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thisresult = fcinfo->flinfo->fn_addr(fcinfo);
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}
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/* Combine results per OR or AND semantics */
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if (fcinfo->isnull)
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resultnull = true;
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*resultnull = true;
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else if (useOr)
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{
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if (DatumGetBool(thisresult))
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{
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result = BoolGetDatum(true);
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resultnull = false;
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*result = BoolGetDatum(true);
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*resultnull = false;
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break; /* needn't look at any more elements */
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}
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}
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@ -3434,8 +3465,8 @@ ExecEvalScalarArrayOp(ExprState *state, ExprEvalStep *op)
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{
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if (!DatumGetBool(thisresult))
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{
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result = BoolGetDatum(false);
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resultnull = false;
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*result = BoolGetDatum(false);
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*resultnull = false;
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break; /* needn't look at any more elements */
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}
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}
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@ -3451,9 +3482,6 @@ ExecEvalScalarArrayOp(ExprState *state, ExprEvalStep *op)
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}
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}
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}
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*op->resvalue = result;
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*op->resnull = resultnull;
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}
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/*
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@ -3532,7 +3560,7 @@ ExecEvalHashedScalarArrayOp(ExprState *state, ExprEvalStep *op, ExprContext *eco
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* If the scalar is NULL, and the function is strict, return NULL; no
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* point in executing the search.
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*/
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if (fcinfo->args[0].isnull && strictfunc)
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if (scalar_isnull && strictfunc)
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{
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*op->resnull = true;
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return;
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@ -3630,8 +3658,51 @@ ExecEvalHashedScalarArrayOp(ExprState *state, ExprEvalStep *op, ExprContext *eco
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* non-strict functions with a null lhs value if no match is found.
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*/
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op->d.hashedscalararrayop.has_nulls = has_nulls;
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/*
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* When we have a non-strict equality function, check and cache the
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* result from looking up a NULL. Non-strict functions are free to
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* treat a NULL as equal to any other value, e.g. a 0 or an empty
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* string. Here we perform a linear search over the array and cache
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* the outcome so that we can use that result any time we receive a
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* NULL.
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*/
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if (!strictfunc)
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{
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bool null_lhs_result;
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fcinfo->args[0].value = (Datum) 0;
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fcinfo->args[0].isnull = true;
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ExecEvalArrayCompareInternal(fcinfo, arr, typlen, typbyval,
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typalign, true, &result,
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&resultnull);
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null_lhs_result = DatumGetBool(result);
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/* invert non-NULL results for NOT IN */
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if (!resultnull && !inclause)
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null_lhs_result = !null_lhs_result;
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op->d.hashedscalararrayop.null_lhs_isnull = resultnull;
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op->d.hashedscalararrayop.null_lhs_result = null_lhs_result;
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}
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}
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/*
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* When looking up an SQL NULL value with non-strict functions, we defer
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* to the value we cached when building the hash table.
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*/
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if (scalar_isnull)
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{
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Assert(!strictfunc);
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*op->resnull = op->d.hashedscalararrayop.null_lhs_isnull;
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*op->resvalue = BoolGetDatum(op->d.hashedscalararrayop.null_lhs_result);
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return;
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}
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/* Check the hash to see if we have a match. */
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hashfound = NULL != saophash_lookup(elements_tab->hashtab, scalar);
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@ -576,6 +576,10 @@ typedef struct ExprEvalStep
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{
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bool has_nulls;
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bool inclause; /* true for IN and false for NOT IN */
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bool null_lhs_result; /* for non-strict lookups, we
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* cache what looking up NULL
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* returns. */
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bool null_lhs_isnull;
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struct ScalarArrayOpExprHashTable *elements_tab;
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FmgrInfo *finfo; /* function's lookup data */
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FunctionCallInfo fcinfo_data; /* arguments etc */
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@ -353,42 +353,177 @@ default for type myint using hash as
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operator 1 = (myint, myint),
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function 1 myinthash(myint);
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create table inttest (a myint);
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insert into inttest values(1::myint),(null);
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-- try an array with enough elements to cause hashing
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select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
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a
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---
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1
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(2 rows)
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insert into inttest values (null), (0::myint), (1::myint);
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-- Test EEOP_HASHED_SCALARARRAYOP against EEOP_SCALARARRAYOP. Ensure the
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-- result of non-hashed vs hashed is the same.
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select
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a,
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a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
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a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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0 | f | f
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1 | t | t
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(3 rows)
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select * from inttest where a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
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a
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---
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(0 rows)
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select
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a,
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a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
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a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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| t | t
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0 | |
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1 | t | t
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(3 rows)
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select * from inttest where a not in (0::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
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a
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---
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(0 rows)
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select
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a,
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a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
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a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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| |
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0 | t | t
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1 | f | f
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(3 rows)
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-- ensure the result matched with the non-hashed version. We simply remove
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-- some array elements so that we don't reach the hashing threshold.
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select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint, null);
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a
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---
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1
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(2 rows)
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select
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a,
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a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
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a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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| f | f
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0 | |
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1 | f | f
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(3 rows)
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select * from inttest where a not in (1::myint,2::myint,3::myint,4::myint,5::myint, null);
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a
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---
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(0 rows)
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-- Now make the equal function return false when given two NULLs
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create or replace function myinteq(myint, myint) returns bool as $$
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begin
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if $1 is null and $2 is null then
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return false;
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else
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return $1::int = $2::int;
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end if;
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end;
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$$ language plpgsql immutable;
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-- And try the same again to ensure EEOP_HASHED_SCALARARRAYOP does the same
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-- thing as EEOP_SCALARARRAYOP.
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select
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a,
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a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
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a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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| |
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0 | f | f
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1 | t | t
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(3 rows)
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select * from inttest where a not in (0::myint,2::myint,3::myint,4::myint,5::myint, null);
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a
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---
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(0 rows)
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select
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a,
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a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
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a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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| |
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0 | |
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1 | t | t
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(3 rows)
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select
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a,
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a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
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a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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| |
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0 | t | t
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1 | f | f
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(3 rows)
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select
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a,
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a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
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a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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| |
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0 | |
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1 | f | f
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(3 rows)
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-- Try again with an equality function that treats NULLs as equal to 0.
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create or replace function myinteq(myint, myint) returns bool as $$
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begin
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if $1 is null and $2 is null then
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return false;
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else
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return coalesce($1::int,0) = coalesce($2::int, 0);
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end if;
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end;
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$$ language plpgsql immutable;
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select
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a,
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a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
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a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed,
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a in (0::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed_zero,
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a in (0::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed_zero
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from inttest;
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a | not_hashed | hashed | not_hashed_zero | hashed_zero
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---+------------+--------+-----------------+-------------
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| f | f | t | t
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0 | f | f | t | t
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1 | t | t | t | t
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(3 rows)
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select
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a,
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a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
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a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
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from inttest;
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a | not_hashed | hashed
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---+------------+--------
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| f | f
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0 | t | t
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1 | t | t
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(3 rows)
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select
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a,
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a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
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a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed,
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a not in (0::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed_zero,
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a not in (0::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed_zero
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from inttest;
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a | not_hashed | hashed | not_hashed_zero | hashed_zero
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---+------------+--------+-----------------+-------------
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| t | t | f | f
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0 | t | t | f | f
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1 | f | f | f | f
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(3 rows)
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select
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a,
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a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
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a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
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from inttest;
|
||||
a | not_hashed | hashed
|
||||
---+------------+--------
|
||||
| t | t
|
||||
0 | f | f
|
||||
1 | f | f
|
||||
(3 rows)
|
||||
|
||||
rollback;
|
||||
|
|
|
|||
|
|
@ -191,16 +191,108 @@ default for type myint using hash as
|
|||
function 1 myinthash(myint);
|
||||
|
||||
create table inttest (a myint);
|
||||
insert into inttest values(1::myint),(null);
|
||||
insert into inttest values (null), (0::myint), (1::myint);
|
||||
|
||||
-- try an array with enough elements to cause hashing
|
||||
select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
|
||||
select * from inttest where a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
|
||||
select * from inttest where a not in (0::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
|
||||
-- ensure the result matched with the non-hashed version. We simply remove
|
||||
-- some array elements so that we don't reach the hashing threshold.
|
||||
select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint, null);
|
||||
select * from inttest where a not in (1::myint,2::myint,3::myint,4::myint,5::myint, null);
|
||||
select * from inttest where a not in (0::myint,2::myint,3::myint,4::myint,5::myint, null);
|
||||
-- Test EEOP_HASHED_SCALARARRAYOP against EEOP_SCALARARRAYOP. Ensure the
|
||||
-- result of non-hashed vs hashed is the same.
|
||||
select
|
||||
a,
|
||||
a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
|
||||
a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
|
||||
a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
|
||||
a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
|
||||
a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
-- Now make the equal function return false when given two NULLs
|
||||
create or replace function myinteq(myint, myint) returns bool as $$
|
||||
begin
|
||||
if $1 is null and $2 is null then
|
||||
return false;
|
||||
else
|
||||
return $1::int = $2::int;
|
||||
end if;
|
||||
end;
|
||||
$$ language plpgsql immutable;
|
||||
|
||||
-- And try the same again to ensure EEOP_HASHED_SCALARARRAYOP does the same
|
||||
-- thing as EEOP_SCALARARRAYOP.
|
||||
select
|
||||
a,
|
||||
a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
|
||||
a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
|
||||
a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
|
||||
a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
|
||||
a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
-- Try again with an equality function that treats NULLs as equal to 0.
|
||||
create or replace function myinteq(myint, myint) returns bool as $$
|
||||
begin
|
||||
if $1 is null and $2 is null then
|
||||
return false;
|
||||
else
|
||||
return coalesce($1::int,0) = coalesce($2::int, 0);
|
||||
end if;
|
||||
end;
|
||||
$$ language plpgsql immutable;
|
||||
|
||||
select
|
||||
a,
|
||||
a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
|
||||
a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed,
|
||||
a in (0::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed_zero,
|
||||
a in (0::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed_zero
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
|
||||
a in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as not_hashed,
|
||||
a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint) as hashed,
|
||||
a not in (0::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed_zero,
|
||||
a not in (0::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed_zero
|
||||
from inttest;
|
||||
|
||||
select
|
||||
a,
|
||||
a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint) as not_hashed,
|
||||
a not in (null::myint,1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint) as hashed
|
||||
from inttest;
|
||||
|
||||
rollback;
|
||||
|
|
|
|||
Loading…
Reference in a new issue