aggregatecmds.c

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/*-------------------------------------------------------------------------
 *
 * aggregatecmds.c
 *
 *    Routines for aggregate-manipulation commands
 *
 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/commands/aggregatecmds.c
 *
 * DESCRIPTION
 *    The "DefineFoo" routines take the parse tree and pick out the
 *    appropriate arguments/flags, passing the results to the
 *    corresponding "FooDefine" routines (in src/catalog) that do
 *    the actual catalog-munging.  These routines also verify permission
 *    of the user to execute the command.
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/htup_details.h"
#include "catalog/dependency.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/alter.h"
#include "commands/defrem.h"
#include "miscadmin.h"
#include "parser/parse_func.h"
#include "parser/parse_type.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"


static char extractModify(DefElem *defel);


/*
 *  DefineAggregate
 *
 * "oldstyle" signals the old (pre-8.2) style where the aggregate input type
 * is specified by a BASETYPE element in the parameters.  Otherwise,
 * "args" is a pair, whose first element is a list of FunctionParameter structs
 * defining the agg's arguments (both direct and aggregated), and whose second
 * element is an Integer node with the number of direct args, or -1 if this
 * isn't an ordered-set aggregate.
 * "parameters" is a list of DefElem representing the agg's definition clauses.
 */
ObjectAddress
DefineAggregate(ParseState *pstate,
                List *name,
                List *args,
                bool oldstyle,
                List *parameters,
                bool replace)
{
    char       *aggName;
    Oid         aggNamespace;
    AclResult   aclresult;
    char        aggKind = AGGKIND_NORMAL;
    List       *transfuncName = NIL;
    List       *finalfuncName = NIL;
    List       *combinefuncName = NIL;
    List       *serialfuncName = NIL;
    List       *deserialfuncName = NIL;
    List       *mtransfuncName = NIL;
    List       *minvtransfuncName = NIL;
    List       *mfinalfuncName = NIL;
    bool        finalfuncExtraArgs = false;
    bool        mfinalfuncExtraArgs = false;
    char        finalfuncModify = 0;
    char        mfinalfuncModify = 0;
    List       *sortoperatorName = NIL;
    TypeName   *baseType = NULL;
    TypeName   *transType = NULL;
    TypeName   *mtransType = NULL;
    int32       transSpace = 0;
    int32       mtransSpace = 0;
    char       *initval = NULL;
    char       *minitval = NULL;
    char       *parallel = NULL;
    int         numArgs;
    int         numDirectArgs = 0;
    oidvector  *parameterTypes;
    ArrayType  *allParameterTypes;
    ArrayType  *parameterModes;
    ArrayType  *parameterNames;
    List       *parameterDefaults;
    Oid         variadicArgType;
    Oid         transTypeId;
    Oid         mtransTypeId = InvalidOid;
    char        transTypeType;
    char        mtransTypeType = 0;
    char        proparallel = PROPARALLEL_UNSAFE;
    ListCell   *pl;

    /* Convert list of names to a name and namespace */
    aggNamespace = QualifiedNameGetCreationNamespace(name, &aggName);

    /* Check we have creation rights in target namespace */
    aclresult = pg_namespace_aclcheck(aggNamespace, GetUserId(), ACL_CREATE);
    if (aclresult != ACLCHECK_OK)
        aclcheck_error(aclresult, OBJECT_SCHEMA,
                       get_namespace_name(aggNamespace));

    /* Deconstruct the output of the aggr_args grammar production */
    if (!oldstyle)
    {
        Assert(list_length(args) == 2);
        numDirectArgs = intVal(lsecond(args));
        if (numDirectArgs >= 0)
            aggKind = AGGKIND_ORDERED_SET;
        else
            numDirectArgs = 0;
        args = linitial_node(List, args);
    }

    /* Examine aggregate's definition clauses */
    foreach(pl, parameters)
    {
        DefElem    *defel = lfirst_node(DefElem, pl);

        /*
         * sfunc1, stype1, and initcond1 are accepted as obsolete spellings
         * for sfunc, stype, initcond.
         */
        if (strcmp(defel->defname, "sfunc") == 0)
            transfuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "sfunc1") == 0)
            transfuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "finalfunc") == 0)
            finalfuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "combinefunc") == 0)
            combinefuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "serialfunc") == 0)
            serialfuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "deserialfunc") == 0)
            deserialfuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "msfunc") == 0)
            mtransfuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "minvfunc") == 0)
            minvtransfuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "mfinalfunc") == 0)
            mfinalfuncName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "finalfunc_extra") == 0)
            finalfuncExtraArgs = defGetBoolean(defel);
        else if (strcmp(defel->defname, "mfinalfunc_extra") == 0)
            mfinalfuncExtraArgs = defGetBoolean(defel);
        else if (strcmp(defel->defname, "finalfunc_modify") == 0)
            finalfuncModify = extractModify(defel);
        else if (strcmp(defel->defname, "mfinalfunc_modify") == 0)
            mfinalfuncModify = extractModify(defel);
        else if (strcmp(defel->defname, "sortop") == 0)
            sortoperatorName = defGetQualifiedName(defel);
        else if (strcmp(defel->defname, "basetype") == 0)
            baseType = defGetTypeName(defel);
        else if (strcmp(defel->defname, "hypothetical") == 0)
        {
            if (defGetBoolean(defel))
            {
                if (aggKind == AGGKIND_NORMAL)
                    ereport(ERROR,
                            (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                             errmsg("only ordered-set aggregates can be hypothetical")));
                aggKind = AGGKIND_HYPOTHETICAL;
            }
        }
        else if (strcmp(defel->defname, "stype") == 0)
            transType = defGetTypeName(defel);
        else if (strcmp(defel->defname, "stype1") == 0)
            transType = defGetTypeName(defel);
        else if (strcmp(defel->defname, "sspace") == 0)
            transSpace = defGetInt32(defel);
        else if (strcmp(defel->defname, "mstype") == 0)
            mtransType = defGetTypeName(defel);
        else if (strcmp(defel->defname, "msspace") == 0)
            mtransSpace = defGetInt32(defel);
        else if (strcmp(defel->defname, "initcond") == 0)
            initval = defGetString(defel);
        else if (strcmp(defel->defname, "initcond1") == 0)
            initval = defGetString(defel);
        else if (strcmp(defel->defname, "minitcond") == 0)
            minitval = defGetString(defel);
        else if (strcmp(defel->defname, "parallel") == 0)
            parallel = defGetString(defel);
        else
            ereport(WARNING,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("aggregate attribute \"%s\" not recognized",
                            defel->defname)));
    }

    /*
     * make sure we have our required definitions
     */
    if (transType == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                 errmsg("aggregate stype must be specified")));
    if (transfuncName == NIL)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                 errmsg("aggregate sfunc must be specified")));

    /*
     * if mtransType is given, mtransfuncName and minvtransfuncName must be as
     * well; if not, then none of the moving-aggregate options should have
     * been given.
     */
    if (mtransType != NULL)
    {
        if (mtransfuncName == NIL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate msfunc must be specified when mstype is specified")));
        if (minvtransfuncName == NIL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate minvfunc must be specified when mstype is specified")));
    }
    else
    {
        if (mtransfuncName != NIL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate msfunc must not be specified without mstype")));
        if (minvtransfuncName != NIL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate minvfunc must not be specified without mstype")));
        if (mfinalfuncName != NIL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate mfinalfunc must not be specified without mstype")));
        if (mtransSpace != 0)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate msspace must not be specified without mstype")));
        if (minitval != NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate minitcond must not be specified without mstype")));
    }

    /*
     * Default values for modify flags can only be determined once we know the
     * aggKind.
     */
    if (finalfuncModify == 0)
        finalfuncModify = (aggKind == AGGKIND_NORMAL) ? AGGMODIFY_READ_ONLY : AGGMODIFY_READ_WRITE;
    if (mfinalfuncModify == 0)
        mfinalfuncModify = (aggKind == AGGKIND_NORMAL) ? AGGMODIFY_READ_ONLY : AGGMODIFY_READ_WRITE;

    /*
     * look up the aggregate's input datatype(s).
     */
    if (oldstyle)
    {
        /*
         * Old style: use basetype parameter.  This supports aggregates of
         * zero or one input, with input type ANY meaning zero inputs.
         *
         * Historically we allowed the command to look like basetype = 'ANY'
         * so we must do a case-insensitive comparison for the name ANY. Ugh.
         */
        Oid         aggArgTypes[1];

        if (baseType == NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate input type must be specified")));

        if (pg_strcasecmp(TypeNameToString(baseType), "ANY") == 0)
        {
            numArgs = 0;
            aggArgTypes[0] = InvalidOid;
        }
        else
        {
            numArgs = 1;
            aggArgTypes[0] = typenameTypeId(NULL, baseType);
        }
        parameterTypes = buildoidvector(aggArgTypes, numArgs);
        allParameterTypes = NULL;
        parameterModes = NULL;
        parameterNames = NULL;
        parameterDefaults = NIL;
        variadicArgType = InvalidOid;
    }
    else
    {
        /*
         * New style: args is a list of FunctionParameters (possibly zero of
         * 'em).  We share functioncmds.c's code for processing them.
         */
        Oid         requiredResultType;

        if (baseType != NULL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("basetype is redundant with aggregate input type specification")));

        numArgs = list_length(args);
        interpret_function_parameter_list(pstate,
                                          args,
                                          InvalidOid,
                                          OBJECT_AGGREGATE,
                                          &parameterTypes,
                                          &allParameterTypes,
                                          &parameterModes,
                                          &parameterNames,
                                          &parameterDefaults,
                                          &variadicArgType,
                                          &requiredResultType);
        /* Parameter defaults are not currently allowed by the grammar */
        Assert(parameterDefaults == NIL);
        /* There shouldn't have been any OUT parameters, either */
        Assert(requiredResultType == InvalidOid);
    }

    /*
     * look up the aggregate's transtype.
     *
     * transtype can't be a pseudo-type, since we need to be able to store
     * values of the transtype.  However, we can allow polymorphic transtype
     * in some cases (AggregateCreate will check).  Also, we allow "internal"
     * for functions that want to pass pointers to private data structures;
     * but allow that only to superusers, since you could crash the system (or
     * worse) by connecting up incompatible internal-using functions in an
     * aggregate.
     */
    transTypeId = typenameTypeId(NULL, transType);
    transTypeType = get_typtype(transTypeId);
    if (transTypeType == TYPTYPE_PSEUDO &&
        !IsPolymorphicType(transTypeId))
    {
        if (transTypeId == INTERNALOID && superuser())
             /* okay */ ;
        else
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("aggregate transition data type cannot be %s",
                            format_type_be(transTypeId))));
    }

    if (serialfuncName && deserialfuncName)
    {
        /*
         * Serialization is only needed/allowed for transtype INTERNAL.
         */
        if (transTypeId != INTERNALOID)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                     errmsg("serialization functions may be specified only when the aggregate transition data type is %s",
                            format_type_be(INTERNALOID))));
    }
    else if (serialfuncName || deserialfuncName)
    {
        /*
         * Cannot specify one function without the other.
         */
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                 errmsg("must specify both or neither of serialization and deserialization functions")));
    }

    /*
     * If a moving-aggregate transtype is specified, look that up.  Same
     * restrictions as for transtype.
     */
    if (mtransType)
    {
        mtransTypeId = typenameTypeId(NULL, mtransType);
        mtransTypeType = get_typtype(mtransTypeId);
        if (mtransTypeType == TYPTYPE_PSEUDO &&
            !IsPolymorphicType(mtransTypeId))
        {
            if (mtransTypeId == INTERNALOID && superuser())
                 /* okay */ ;
            else
                ereport(ERROR,
                        (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                         errmsg("aggregate transition data type cannot be %s",
                                format_type_be(mtransTypeId))));
        }
    }

    /*
     * If we have an initval, and it's not for a pseudotype (particularly a
     * polymorphic type), make sure it's acceptable to the type's input
     * function.  We will store the initval as text, because the input
     * function isn't necessarily immutable (consider "now" for timestamp),
     * and we want to use the runtime not creation-time interpretation of the
     * value.  However, if it's an incorrect value it seems much more
     * user-friendly to complain at CREATE AGGREGATE time.
     */
    if (initval && transTypeType != TYPTYPE_PSEUDO)
    {
        Oid         typinput,
                    typioparam;

        getTypeInputInfo(transTypeId, &typinput, &typioparam);
        (void) OidInputFunctionCall(typinput, initval, typioparam, -1);
    }

    /*
     * Likewise for moving-aggregate initval.
     */
    if (minitval && mtransTypeType != TYPTYPE_PSEUDO)
    {
        Oid         typinput,
                    typioparam;

        getTypeInputInfo(mtransTypeId, &typinput, &typioparam);
        (void) OidInputFunctionCall(typinput, minitval, typioparam, -1);
    }

    if (parallel)
    {
        if (strcmp(parallel, "safe") == 0)
            proparallel = PROPARALLEL_SAFE;
        else if (strcmp(parallel, "restricted") == 0)
            proparallel = PROPARALLEL_RESTRICTED;
        else if (strcmp(parallel, "unsafe") == 0)
            proparallel = PROPARALLEL_UNSAFE;
        else
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("parameter \"parallel\" must be SAFE, RESTRICTED, or UNSAFE")));
    }

    /*
     * Most of the argument-checking is done inside of AggregateCreate
     */
    return AggregateCreate(aggName, /* aggregate name */
                           aggNamespace,    /* namespace */
                           replace,
                           aggKind,
                           numArgs,
                           numDirectArgs,
                           parameterTypes,
                           PointerGetDatum(allParameterTypes),
                           PointerGetDatum(parameterModes),
                           PointerGetDatum(parameterNames),
                           parameterDefaults,
                           variadicArgType,
                           transfuncName,   /* step function name */
                           finalfuncName,   /* final function name */
                           combinefuncName, /* combine function name */
                           serialfuncName,  /* serial function name */
                           deserialfuncName,    /* deserial function name */
                           mtransfuncName,  /* fwd trans function name */
                           minvtransfuncName,   /* inv trans function name */
                           mfinalfuncName,  /* final function name */
                           finalfuncExtraArgs,
                           mfinalfuncExtraArgs,
                           finalfuncModify,
                           mfinalfuncModify,
                           sortoperatorName,    /* sort operator name */
                           transTypeId, /* transition data type */
                           transSpace,  /* transition space */
                           mtransTypeId,    /* transition data type */
                           mtransSpace, /* transition space */
                           initval, /* initial condition */
                           minitval,    /* initial condition */
                           proparallel);    /* parallel safe? */
}

/*
 * Convert the string form of [m]finalfunc_modify to the catalog representation
 */
static char
extractModify(DefElem *defel)
{
    char       *val = defGetString(defel);

    if (strcmp(val, "read_only") == 0)
        return AGGMODIFY_READ_ONLY;
    if (strcmp(val, "shareable") == 0)
        return AGGMODIFY_SHAREABLE;
    if (strcmp(val, "read_write") == 0)
        return AGGMODIFY_READ_WRITE;
    ereport(ERROR,
            (errcode(ERRCODE_SYNTAX_ERROR),
             errmsg("parameter \"%s\" must be READ_ONLY, SHAREABLE, or READ_WRITE",
                    defel->defname)));
    return 0;                   /* keep compiler quiet */
}