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Diffstat (limited to 'contrib/tablefunc/tablefunc.c')
| -rw-r--r-- | contrib/tablefunc/tablefunc.c | 1592 |
1 files changed, 1592 insertions, 0 deletions
diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c new file mode 100644 index 0000000..779bd44 --- /dev/null +++ b/contrib/tablefunc/tablefunc.c @@ -0,0 +1,1592 @@ +/* + * contrib/tablefunc/tablefunc.c + * + * + * tablefunc + * + * Sample to demonstrate C functions which return setof scalar + * and setof composite. + * Joe Conway <mail@joeconway.com> + * And contributors: + * Nabil Sayegh <postgresql@e-trolley.de> + * + * Copyright (c) 2002-2021, PostgreSQL Global Development Group + * + * Permission to use, copy, modify, and distribute this software and its + * documentation for any purpose, without fee, and without a written agreement + * is hereby granted, provided that the above copyright notice and this + * paragraph and the following two paragraphs appear in all copies. + * + * IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR + * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING + * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS + * DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + * THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES, + * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS + * ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO + * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + * + */ +#include "postgres.h" + +#include <math.h> + +#include "access/htup_details.h" +#include "catalog/pg_type.h" +#include "executor/spi.h" +#include "funcapi.h" +#include "lib/stringinfo.h" +#include "miscadmin.h" +#include "tablefunc.h" +#include "utils/builtins.h" + +PG_MODULE_MAGIC; + +static HTAB *load_categories_hash(char *cats_sql, MemoryContext per_query_ctx); +static Tuplestorestate *get_crosstab_tuplestore(char *sql, + HTAB *crosstab_hash, + TupleDesc tupdesc, + bool randomAccess); +static void validateConnectbyTupleDesc(TupleDesc tupdesc, bool show_branch, bool show_serial); +static bool compatCrosstabTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2); +static void compatConnectbyTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2); +static void get_normal_pair(float8 *x1, float8 *x2); +static Tuplestorestate *connectby(char *relname, + char *key_fld, + char *parent_key_fld, + char *orderby_fld, + char *branch_delim, + char *start_with, + int max_depth, + bool show_branch, + bool show_serial, + MemoryContext per_query_ctx, + bool randomAccess, + AttInMetadata *attinmeta); +static void build_tuplestore_recursively(char *key_fld, + char *parent_key_fld, + char *relname, + char *orderby_fld, + char *branch_delim, + char *start_with, + char *branch, + int level, + int *serial, + int max_depth, + bool show_branch, + bool show_serial, + MemoryContext per_query_ctx, + AttInMetadata *attinmeta, + Tuplestorestate *tupstore); + +typedef struct +{ + float8 mean; /* mean of the distribution */ + float8 stddev; /* stddev of the distribution */ + float8 carry_val; /* hold second generated value */ + bool use_carry; /* use second generated value */ +} normal_rand_fctx; + +#define xpfree(var_) \ + do { \ + if (var_ != NULL) \ + { \ + pfree(var_); \ + var_ = NULL; \ + } \ + } while (0) + +#define xpstrdup(tgtvar_, srcvar_) \ + do { \ + if (srcvar_) \ + tgtvar_ = pstrdup(srcvar_); \ + else \ + tgtvar_ = NULL; \ + } while (0) + +#define xstreq(tgtvar_, srcvar_) \ + (((tgtvar_ == NULL) && (srcvar_ == NULL)) || \ + ((tgtvar_ != NULL) && (srcvar_ != NULL) && (strcmp(tgtvar_, srcvar_) == 0))) + +/* sign, 10 digits, '\0' */ +#define INT32_STRLEN 12 + +/* stored info for a crosstab category */ +typedef struct crosstab_cat_desc +{ + char *catname; /* full category name */ + uint64 attidx; /* zero based */ +} crosstab_cat_desc; + +#define MAX_CATNAME_LEN NAMEDATALEN +#define INIT_CATS 64 + +#define crosstab_HashTableLookup(HASHTAB, CATNAME, CATDESC) \ +do { \ + crosstab_HashEnt *hentry; char key[MAX_CATNAME_LEN]; \ + \ + MemSet(key, 0, MAX_CATNAME_LEN); \ + snprintf(key, MAX_CATNAME_LEN - 1, "%s", CATNAME); \ + hentry = (crosstab_HashEnt*) hash_search(HASHTAB, \ + key, HASH_FIND, NULL); \ + if (hentry) \ + CATDESC = hentry->catdesc; \ + else \ + CATDESC = NULL; \ +} while(0) + +#define crosstab_HashTableInsert(HASHTAB, CATDESC) \ +do { \ + crosstab_HashEnt *hentry; bool found; char key[MAX_CATNAME_LEN]; \ + \ + MemSet(key, 0, MAX_CATNAME_LEN); \ + snprintf(key, MAX_CATNAME_LEN - 1, "%s", CATDESC->catname); \ + hentry = (crosstab_HashEnt*) hash_search(HASHTAB, \ + key, HASH_ENTER, &found); \ + if (found) \ + ereport(ERROR, \ + (errcode(ERRCODE_DUPLICATE_OBJECT), \ + errmsg("duplicate category name"))); \ + hentry->catdesc = CATDESC; \ +} while(0) + +/* hash table */ +typedef struct crosstab_hashent +{ + char internal_catname[MAX_CATNAME_LEN]; + crosstab_cat_desc *catdesc; +} crosstab_HashEnt; + +/* + * normal_rand - return requested number of random values + * with a Gaussian (Normal) distribution. + * + * inputs are int numvals, float8 mean, and float8 stddev + * returns setof float8 + */ +PG_FUNCTION_INFO_V1(normal_rand); +Datum +normal_rand(PG_FUNCTION_ARGS) +{ + FuncCallContext *funcctx; + uint64 call_cntr; + uint64 max_calls; + normal_rand_fctx *fctx; + float8 mean; + float8 stddev; + float8 carry_val; + bool use_carry; + MemoryContext oldcontext; + + /* stuff done only on the first call of the function */ + if (SRF_IS_FIRSTCALL()) + { + int32 num_tuples; + + /* create a function context for cross-call persistence */ + funcctx = SRF_FIRSTCALL_INIT(); + + /* + * switch to memory context appropriate for multiple function calls + */ + oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx); + + /* total number of tuples to be returned */ + num_tuples = PG_GETARG_INT32(0); + if (num_tuples < 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("number of rows cannot be negative"))); + funcctx->max_calls = num_tuples; + + /* allocate memory for user context */ + fctx = (normal_rand_fctx *) palloc(sizeof(normal_rand_fctx)); + + /* + * Use fctx to keep track of upper and lower bounds from call to call. + * It will also be used to carry over the spare value we get from the + * Box-Muller algorithm so that we only actually calculate a new value + * every other call. + */ + fctx->mean = PG_GETARG_FLOAT8(1); + fctx->stddev = PG_GETARG_FLOAT8(2); + fctx->carry_val = 0; + fctx->use_carry = false; + + funcctx->user_fctx = fctx; + + MemoryContextSwitchTo(oldcontext); + } + + /* stuff done on every call of the function */ + funcctx = SRF_PERCALL_SETUP(); + + call_cntr = funcctx->call_cntr; + max_calls = funcctx->max_calls; + fctx = funcctx->user_fctx; + mean = fctx->mean; + stddev = fctx->stddev; + carry_val = fctx->carry_val; + use_carry = fctx->use_carry; + + if (call_cntr < max_calls) /* do when there is more left to send */ + { + float8 result; + + if (use_carry) + { + /* + * reset use_carry and use second value obtained on last pass + */ + fctx->use_carry = false; + result = carry_val; + } + else + { + float8 normval_1; + float8 normval_2; + + /* Get the next two normal values */ + get_normal_pair(&normval_1, &normval_2); + + /* use the first */ + result = mean + (stddev * normval_1); + + /* and save the second */ + fctx->carry_val = mean + (stddev * normval_2); + fctx->use_carry = true; + } + + /* send the result */ + SRF_RETURN_NEXT(funcctx, Float8GetDatum(result)); + } + else + /* do when there is no more left */ + SRF_RETURN_DONE(funcctx); +} + +/* + * get_normal_pair() + * Assigns normally distributed (Gaussian) values to a pair of provided + * parameters, with mean 0, standard deviation 1. + * + * This routine implements Algorithm P (Polar method for normal deviates) + * from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages + * 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E. + * Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611. + * + */ +static void +get_normal_pair(float8 *x1, float8 *x2) +{ + float8 u1, + u2, + v1, + v2, + s; + + do + { + u1 = (float8) random() / (float8) MAX_RANDOM_VALUE; + u2 = (float8) random() / (float8) MAX_RANDOM_VALUE; + + v1 = (2.0 * u1) - 1.0; + v2 = (2.0 * u2) - 1.0; + + s = v1 * v1 + v2 * v2; + } while (s >= 1.0); + + if (s == 0) + { + *x1 = 0; + *x2 = 0; + } + else + { + s = sqrt((-2.0 * log(s)) / s); + *x1 = v1 * s; + *x2 = v2 * s; + } +} + +/* + * crosstab - create a crosstab of rowids and values columns from a + * SQL statement returning one rowid column, one category column, + * and one value column. + * + * e.g. given sql which produces: + * + * rowid cat value + * ------+-------+------- + * row1 cat1 val1 + * row1 cat2 val2 + * row1 cat3 val3 + * row1 cat4 val4 + * row2 cat1 val5 + * row2 cat2 val6 + * row2 cat3 val7 + * row2 cat4 val8 + * + * crosstab returns: + * <===== values columns =====> + * rowid cat1 cat2 cat3 cat4 + * ------+-------+-------+-------+------- + * row1 val1 val2 val3 val4 + * row2 val5 val6 val7 val8 + * + * NOTES: + * 1. SQL result must be ordered by 1,2. + * 2. The number of values columns depends on the tuple description + * of the function's declared return type. The return type's columns + * must match the datatypes of the SQL query's result. The datatype + * of the category column can be anything, however. + * 3. Missing values (i.e. not enough adjacent rows of same rowid to + * fill the number of result values columns) are filled in with nulls. + * 4. Extra values (i.e. too many adjacent rows of same rowid to fill + * the number of result values columns) are skipped. + * 5. Rows with all nulls in the values columns are skipped. + */ +PG_FUNCTION_INFO_V1(crosstab); +Datum +crosstab(PG_FUNCTION_ARGS) +{ + char *sql = text_to_cstring(PG_GETARG_TEXT_PP(0)); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + Tuplestorestate *tupstore; + TupleDesc tupdesc; + uint64 call_cntr; + uint64 max_calls; + AttInMetadata *attinmeta; + SPITupleTable *spi_tuptable; + TupleDesc spi_tupdesc; + bool firstpass; + char *lastrowid; + int i; + int num_categories; + MemoryContext per_query_ctx; + MemoryContext oldcontext; + int ret; + uint64 proc; + + /* check to see if caller supports us returning a tuplestore */ + if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("set-valued function called in context that cannot accept a set"))); + if (!(rsinfo->allowedModes & SFRM_Materialize)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("materialize mode required, but it is not allowed in this context"))); + + per_query_ctx = rsinfo->econtext->ecxt_per_query_memory; + + /* Connect to SPI manager */ + if ((ret = SPI_connect()) < 0) + /* internal error */ + elog(ERROR, "crosstab: SPI_connect returned %d", ret); + + /* Retrieve the desired rows */ + ret = SPI_execute(sql, true, 0); + proc = SPI_processed; + + /* If no qualifying tuples, fall out early */ + if (ret != SPI_OK_SELECT || proc == 0) + { + SPI_finish(); + rsinfo->isDone = ExprEndResult; + PG_RETURN_NULL(); + } + + spi_tuptable = SPI_tuptable; + spi_tupdesc = spi_tuptable->tupdesc; + + /*---------- + * The provided SQL query must always return three columns. + * + * 1. rowname + * the label or identifier for each row in the final result + * 2. category + * the label or identifier for each column in the final result + * 3. values + * the value for each column in the final result + *---------- + */ + if (spi_tupdesc->natts != 3) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("invalid source data SQL statement"), + errdetail("The provided SQL must return 3 " + "columns: rowid, category, and values."))); + + /* get a tuple descriptor for our result type */ + switch (get_call_result_type(fcinfo, NULL, &tupdesc)) + { + case TYPEFUNC_COMPOSITE: + /* success */ + break; + case TYPEFUNC_RECORD: + /* failed to determine actual type of RECORD */ + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("function returning record called in context " + "that cannot accept type record"))); + break; + default: + /* result type isn't composite */ + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("return type must be a row type"))); + break; + } + + /* + * Check that return tupdesc is compatible with the data we got from SPI, + * at least based on number and type of attributes + */ + if (!compatCrosstabTupleDescs(tupdesc, spi_tupdesc)) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("return and sql tuple descriptions are " \ + "incompatible"))); + + /* + * switch to long-lived memory context + */ + oldcontext = MemoryContextSwitchTo(per_query_ctx); + + /* make sure we have a persistent copy of the result tupdesc */ + tupdesc = CreateTupleDescCopy(tupdesc); + + /* initialize our tuplestore in long-lived context */ + tupstore = + tuplestore_begin_heap(rsinfo->allowedModes & SFRM_Materialize_Random, + false, work_mem); + + MemoryContextSwitchTo(oldcontext); + + /* + * Generate attribute metadata needed later to produce tuples from raw C + * strings + */ + attinmeta = TupleDescGetAttInMetadata(tupdesc); + + /* total number of tuples to be examined */ + max_calls = proc; + + /* the return tuple always must have 1 rowid + num_categories columns */ + num_categories = tupdesc->natts - 1; + + firstpass = true; + lastrowid = NULL; + + for (call_cntr = 0; call_cntr < max_calls; call_cntr++) + { + bool skip_tuple = false; + char **values; + + /* allocate and zero space */ + values = (char **) palloc0((1 + num_categories) * sizeof(char *)); + + /* + * now loop through the sql results and assign each value in sequence + * to the next category + */ + for (i = 0; i < num_categories; i++) + { + HeapTuple spi_tuple; + char *rowid; + + /* see if we've gone too far already */ + if (call_cntr >= max_calls) + break; + + /* get the next sql result tuple */ + spi_tuple = spi_tuptable->vals[call_cntr]; + + /* get the rowid from the current sql result tuple */ + rowid = SPI_getvalue(spi_tuple, spi_tupdesc, 1); + + /* + * If this is the first pass through the values for this rowid, + * set the first column to rowid + */ + if (i == 0) + { + xpstrdup(values[0], rowid); + + /* + * Check to see if the rowid is the same as that of the last + * tuple sent -- if so, skip this tuple entirely + */ + if (!firstpass && xstreq(lastrowid, rowid)) + { + xpfree(rowid); + skip_tuple = true; + break; + } + } + + /* + * If rowid hasn't changed on us, continue building the output + * tuple. + */ + if (xstreq(rowid, values[0])) + { + /* + * Get the next category item value, which is always attribute + * number three. + * + * Be careful to assign the value to the array index based on + * which category we are presently processing. + */ + values[1 + i] = SPI_getvalue(spi_tuple, spi_tupdesc, 3); + + /* + * increment the counter since we consume a row for each + * category, but not for last pass because the outer loop will + * do that for us + */ + if (i < (num_categories - 1)) + call_cntr++; + xpfree(rowid); + } + else + { + /* + * We'll fill in NULLs for the missing values, but we need to + * decrement the counter since this sql result row doesn't + * belong to the current output tuple. + */ + call_cntr--; + xpfree(rowid); + break; + } + } + + if (!skip_tuple) + { + HeapTuple tuple; + + /* build the tuple and store it */ + tuple = BuildTupleFromCStrings(attinmeta, values); + tuplestore_puttuple(tupstore, tuple); + heap_freetuple(tuple); + } + + /* Remember current rowid */ + xpfree(lastrowid); + xpstrdup(lastrowid, values[0]); + firstpass = false; + + /* Clean up */ + for (i = 0; i < num_categories + 1; i++) + if (values[i] != NULL) + pfree(values[i]); + pfree(values); + } + + /* let the caller know we're sending back a tuplestore */ + rsinfo->returnMode = SFRM_Materialize; + rsinfo->setResult = tupstore; + rsinfo->setDesc = tupdesc; + + /* release SPI related resources (and return to caller's context) */ + SPI_finish(); + + return (Datum) 0; +} + +/* + * crosstab_hash - reimplement crosstab as materialized function and + * properly deal with missing values (i.e. don't pack remaining + * values to the left) + * + * crosstab - create a crosstab of rowids and values columns from a + * SQL statement returning one rowid column, one category column, + * and one value column. + * + * e.g. given sql which produces: + * + * rowid cat value + * ------+-------+------- + * row1 cat1 val1 + * row1 cat2 val2 + * row1 cat4 val4 + * row2 cat1 val5 + * row2 cat2 val6 + * row2 cat3 val7 + * row2 cat4 val8 + * + * crosstab returns: + * <===== values columns =====> + * rowid cat1 cat2 cat3 cat4 + * ------+-------+-------+-------+------- + * row1 val1 val2 null val4 + * row2 val5 val6 val7 val8 + * + * NOTES: + * 1. SQL result must be ordered by 1. + * 2. The number of values columns depends on the tuple description + * of the function's declared return type. + * 3. Missing values (i.e. missing category) are filled in with nulls. + * 4. Extra values (i.e. not in category results) are skipped. + */ +PG_FUNCTION_INFO_V1(crosstab_hash); +Datum +crosstab_hash(PG_FUNCTION_ARGS) +{ + char *sql = text_to_cstring(PG_GETARG_TEXT_PP(0)); + char *cats_sql = text_to_cstring(PG_GETARG_TEXT_PP(1)); + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + TupleDesc tupdesc; + MemoryContext per_query_ctx; + MemoryContext oldcontext; + HTAB *crosstab_hash; + + /* check to see if caller supports us returning a tuplestore */ + if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("set-valued function called in context that cannot accept a set"))); + if (!(rsinfo->allowedModes & SFRM_Materialize) || + rsinfo->expectedDesc == NULL) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("materialize mode required, but it is not allowed in this context"))); + + per_query_ctx = rsinfo->econtext->ecxt_per_query_memory; + oldcontext = MemoryContextSwitchTo(per_query_ctx); + + /* get the requested return tuple description */ + tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc); + + /* + * Check to make sure we have a reasonable tuple descriptor + * + * Note we will attempt to coerce the values into whatever the return + * attribute type is and depend on the "in" function to complain if + * needed. + */ + if (tupdesc->natts < 2) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("query-specified return tuple and " \ + "crosstab function are not compatible"))); + + /* load up the categories hash table */ + crosstab_hash = load_categories_hash(cats_sql, per_query_ctx); + + /* let the caller know we're sending back a tuplestore */ + rsinfo->returnMode = SFRM_Materialize; + + /* now go build it */ + rsinfo->setResult = get_crosstab_tuplestore(sql, + crosstab_hash, + tupdesc, + rsinfo->allowedModes & SFRM_Materialize_Random); + + /* + * SFRM_Materialize mode expects us to return a NULL Datum. The actual + * tuples are in our tuplestore and passed back through rsinfo->setResult. + * rsinfo->setDesc is set to the tuple description that we actually used + * to build our tuples with, so the caller can verify we did what it was + * expecting. + */ + rsinfo->setDesc = tupdesc; + MemoryContextSwitchTo(oldcontext); + + return (Datum) 0; +} + +/* + * load up the categories hash table + */ +static HTAB * +load_categories_hash(char *cats_sql, MemoryContext per_query_ctx) +{ + HTAB *crosstab_hash; + HASHCTL ctl; + int ret; + uint64 proc; + MemoryContext SPIcontext; + + /* initialize the category hash table */ + ctl.keysize = MAX_CATNAME_LEN; + ctl.entrysize = sizeof(crosstab_HashEnt); + ctl.hcxt = per_query_ctx; + + /* + * use INIT_CATS, defined above as a guess of how many hash table entries + * to create, initially + */ + crosstab_hash = hash_create("crosstab hash", + INIT_CATS, + &ctl, + HASH_ELEM | HASH_STRINGS | HASH_CONTEXT); + + /* Connect to SPI manager */ + if ((ret = SPI_connect()) < 0) + /* internal error */ + elog(ERROR, "load_categories_hash: SPI_connect returned %d", ret); + + /* Retrieve the category name rows */ + ret = SPI_execute(cats_sql, true, 0); + proc = SPI_processed; + + /* Check for qualifying tuples */ + if ((ret == SPI_OK_SELECT) && (proc > 0)) + { + SPITupleTable *spi_tuptable = SPI_tuptable; + TupleDesc spi_tupdesc = spi_tuptable->tupdesc; + uint64 i; + + /* + * The provided categories SQL query must always return one column: + * category - the label or identifier for each column + */ + if (spi_tupdesc->natts != 1) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("provided \"categories\" SQL must " \ + "return 1 column of at least one row"))); + + for (i = 0; i < proc; i++) + { + crosstab_cat_desc *catdesc; + char *catname; + HeapTuple spi_tuple; + + /* get the next sql result tuple */ + spi_tuple = spi_tuptable->vals[i]; + + /* get the category from the current sql result tuple */ + catname = SPI_getvalue(spi_tuple, spi_tupdesc, 1); + if (catname == NULL) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("provided \"categories\" SQL must " \ + "not return NULL values"))); + + SPIcontext = MemoryContextSwitchTo(per_query_ctx); + + catdesc = (crosstab_cat_desc *) palloc(sizeof(crosstab_cat_desc)); + catdesc->catname = catname; + catdesc->attidx = i; + + /* Add the proc description block to the hashtable */ + crosstab_HashTableInsert(crosstab_hash, catdesc); + + MemoryContextSwitchTo(SPIcontext); + } + } + + if (SPI_finish() != SPI_OK_FINISH) + /* internal error */ + elog(ERROR, "load_categories_hash: SPI_finish() failed"); + + return crosstab_hash; +} + +/* + * create and populate the crosstab tuplestore using the provided source query + */ +static Tuplestorestate * +get_crosstab_tuplestore(char *sql, + HTAB *crosstab_hash, + TupleDesc tupdesc, + bool randomAccess) +{ + Tuplestorestate *tupstore; + int num_categories = hash_get_num_entries(crosstab_hash); + AttInMetadata *attinmeta = TupleDescGetAttInMetadata(tupdesc); + char **values; + HeapTuple tuple; + int ret; + uint64 proc; + + /* initialize our tuplestore (while still in query context!) */ + tupstore = tuplestore_begin_heap(randomAccess, false, work_mem); + + /* Connect to SPI manager */ + if ((ret = SPI_connect()) < 0) + /* internal error */ + elog(ERROR, "get_crosstab_tuplestore: SPI_connect returned %d", ret); + + /* Now retrieve the crosstab source rows */ + ret = SPI_execute(sql, true, 0); + proc = SPI_processed; + + /* Check for qualifying tuples */ + if ((ret == SPI_OK_SELECT) && (proc > 0)) + { + SPITupleTable *spi_tuptable = SPI_tuptable; + TupleDesc spi_tupdesc = spi_tuptable->tupdesc; + int ncols = spi_tupdesc->natts; + char *rowid; + char *lastrowid = NULL; + bool firstpass = true; + uint64 i; + int j; + int result_ncols; + + if (num_categories == 0) + { + /* no qualifying category tuples */ + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("provided \"categories\" SQL must " \ + "return 1 column of at least one row"))); + } + + /* + * The provided SQL query must always return at least three columns: + * + * 1. rowname the label for each row - column 1 in the final result + * 2. category the label for each value-column in the final result 3. + * value the values used to populate the value-columns + * + * If there are more than three columns, the last two are taken as + * "category" and "values". The first column is taken as "rowname". + * Additional columns (2 thru N-2) are assumed the same for the same + * "rowname", and are copied into the result tuple from the first time + * we encounter a particular rowname. + */ + if (ncols < 3) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("invalid source data SQL statement"), + errdetail("The provided SQL must return 3 " \ + " columns; rowid, category, and values."))); + + result_ncols = (ncols - 2) + num_categories; + + /* Recheck to make sure we tuple descriptor still looks reasonable */ + if (tupdesc->natts != result_ncols) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("invalid return type"), + errdetail("Query-specified return " \ + "tuple has %d columns but crosstab " \ + "returns %d.", tupdesc->natts, result_ncols))); + + /* allocate space and make sure it's clear */ + values = (char **) palloc0(result_ncols * sizeof(char *)); + + for (i = 0; i < proc; i++) + { + HeapTuple spi_tuple; + crosstab_cat_desc *catdesc; + char *catname; + + /* get the next sql result tuple */ + spi_tuple = spi_tuptable->vals[i]; + + /* get the rowid from the current sql result tuple */ + rowid = SPI_getvalue(spi_tuple, spi_tupdesc, 1); + + /* + * if we're on a new output row, grab the column values up to + * column N-2 now + */ + if (firstpass || !xstreq(lastrowid, rowid)) + { + /* + * a new row means we need to flush the old one first, unless + * we're on the very first row + */ + if (!firstpass) + { + /* rowid changed, flush the previous output row */ + tuple = BuildTupleFromCStrings(attinmeta, values); + + tuplestore_puttuple(tupstore, tuple); + + for (j = 0; j < result_ncols; j++) + xpfree(values[j]); + } + + values[0] = rowid; + for (j = 1; j < ncols - 2; j++) + values[j] = SPI_getvalue(spi_tuple, spi_tupdesc, j + 1); + + /* we're no longer on the first pass */ + firstpass = false; + } + + /* look up the category and fill in the appropriate column */ + catname = SPI_getvalue(spi_tuple, spi_tupdesc, ncols - 1); + + if (catname != NULL) + { + crosstab_HashTableLookup(crosstab_hash, catname, catdesc); + + if (catdesc) + values[catdesc->attidx + ncols - 2] = + SPI_getvalue(spi_tuple, spi_tupdesc, ncols); + } + + xpfree(lastrowid); + xpstrdup(lastrowid, rowid); + } + + /* flush the last output row */ + tuple = BuildTupleFromCStrings(attinmeta, values); + + tuplestore_puttuple(tupstore, tuple); + } + + if (SPI_finish() != SPI_OK_FINISH) + /* internal error */ + elog(ERROR, "get_crosstab_tuplestore: SPI_finish() failed"); + + tuplestore_donestoring(tupstore); + + return tupstore; +} + +/* + * connectby_text - produce a result set from a hierarchical (parent/child) + * table. + * + * e.g. given table foo: + * + * keyid parent_keyid pos + * ------+------------+-- + * row1 NULL 0 + * row2 row1 0 + * row3 row1 0 + * row4 row2 1 + * row5 row2 0 + * row6 row4 0 + * row7 row3 0 + * row8 row6 0 + * row9 row5 0 + * + * + * connectby(text relname, text keyid_fld, text parent_keyid_fld + * [, text orderby_fld], text start_with, int max_depth + * [, text branch_delim]) + * connectby('foo', 'keyid', 'parent_keyid', 'pos', 'row2', 0, '~') returns: + * + * keyid parent_id level branch serial + * ------+-----------+--------+----------------------- + * row2 NULL 0 row2 1 + * row5 row2 1 row2~row5 2 + * row9 row5 2 row2~row5~row9 3 + * row4 row2 1 row2~row4 4 + * row6 row4 2 row2~row4~row6 5 + * row8 row6 3 row2~row4~row6~row8 6 + * + */ +PG_FUNCTION_INFO_V1(connectby_text); + +#define CONNECTBY_NCOLS 4 +#define CONNECTBY_NCOLS_NOBRANCH 3 + +Datum +connectby_text(PG_FUNCTION_ARGS) +{ + char *relname = text_to_cstring(PG_GETARG_TEXT_PP(0)); + char *key_fld = text_to_cstring(PG_GETARG_TEXT_PP(1)); + char *parent_key_fld = text_to_cstring(PG_GETARG_TEXT_PP(2)); + char *start_with = text_to_cstring(PG_GETARG_TEXT_PP(3)); + int max_depth = PG_GETARG_INT32(4); + char *branch_delim = NULL; + bool show_branch = false; + bool show_serial = false; + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + TupleDesc tupdesc; + AttInMetadata *attinmeta; + MemoryContext per_query_ctx; + MemoryContext oldcontext; + + /* check to see if caller supports us returning a tuplestore */ + if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("set-valued function called in context that cannot accept a set"))); + if (!(rsinfo->allowedModes & SFRM_Materialize) || + rsinfo->expectedDesc == NULL) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("materialize mode required, but it is not allowed in this context"))); + + if (fcinfo->nargs == 6) + { + branch_delim = text_to_cstring(PG_GETARG_TEXT_PP(5)); + show_branch = true; + } + else + /* default is no show, tilde for the delimiter */ + branch_delim = pstrdup("~"); + + per_query_ctx = rsinfo->econtext->ecxt_per_query_memory; + oldcontext = MemoryContextSwitchTo(per_query_ctx); + + /* get the requested return tuple description */ + tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc); + + /* does it meet our needs */ + validateConnectbyTupleDesc(tupdesc, show_branch, show_serial); + + /* OK, use it then */ + attinmeta = TupleDescGetAttInMetadata(tupdesc); + + /* OK, go to work */ + rsinfo->returnMode = SFRM_Materialize; + rsinfo->setResult = connectby(relname, + key_fld, + parent_key_fld, + NULL, + branch_delim, + start_with, + max_depth, + show_branch, + show_serial, + per_query_ctx, + rsinfo->allowedModes & SFRM_Materialize_Random, + attinmeta); + rsinfo->setDesc = tupdesc; + + MemoryContextSwitchTo(oldcontext); + + /* + * SFRM_Materialize mode expects us to return a NULL Datum. The actual + * tuples are in our tuplestore and passed back through rsinfo->setResult. + * rsinfo->setDesc is set to the tuple description that we actually used + * to build our tuples with, so the caller can verify we did what it was + * expecting. + */ + return (Datum) 0; +} + +PG_FUNCTION_INFO_V1(connectby_text_serial); +Datum +connectby_text_serial(PG_FUNCTION_ARGS) +{ + char *relname = text_to_cstring(PG_GETARG_TEXT_PP(0)); + char *key_fld = text_to_cstring(PG_GETARG_TEXT_PP(1)); + char *parent_key_fld = text_to_cstring(PG_GETARG_TEXT_PP(2)); + char *orderby_fld = text_to_cstring(PG_GETARG_TEXT_PP(3)); + char *start_with = text_to_cstring(PG_GETARG_TEXT_PP(4)); + int max_depth = PG_GETARG_INT32(5); + char *branch_delim = NULL; + bool show_branch = false; + bool show_serial = true; + ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; + TupleDesc tupdesc; + AttInMetadata *attinmeta; + MemoryContext per_query_ctx; + MemoryContext oldcontext; + + /* check to see if caller supports us returning a tuplestore */ + if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("set-valued function called in context that cannot accept a set"))); + if (!(rsinfo->allowedModes & SFRM_Materialize) || + rsinfo->expectedDesc == NULL) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("materialize mode required, but it is not allowed in this context"))); + + if (fcinfo->nargs == 7) + { + branch_delim = text_to_cstring(PG_GETARG_TEXT_PP(6)); + show_branch = true; + } + else + /* default is no show, tilde for the delimiter */ + branch_delim = pstrdup("~"); + + per_query_ctx = rsinfo->econtext->ecxt_per_query_memory; + oldcontext = MemoryContextSwitchTo(per_query_ctx); + + /* get the requested return tuple description */ + tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc); + + /* does it meet our needs */ + validateConnectbyTupleDesc(tupdesc, show_branch, show_serial); + + /* OK, use it then */ + attinmeta = TupleDescGetAttInMetadata(tupdesc); + + /* OK, go to work */ + rsinfo->returnMode = SFRM_Materialize; + rsinfo->setResult = connectby(relname, + key_fld, + parent_key_fld, + orderby_fld, + branch_delim, + start_with, + max_depth, + show_branch, + show_serial, + per_query_ctx, + rsinfo->allowedModes & SFRM_Materialize_Random, + attinmeta); + rsinfo->setDesc = tupdesc; + + MemoryContextSwitchTo(oldcontext); + + /* + * SFRM_Materialize mode expects us to return a NULL Datum. The actual + * tuples are in our tuplestore and passed back through rsinfo->setResult. + * rsinfo->setDesc is set to the tuple description that we actually used + * to build our tuples with, so the caller can verify we did what it was + * expecting. + */ + return (Datum) 0; +} + + +/* + * connectby - does the real work for connectby_text() + */ +static Tuplestorestate * +connectby(char *relname, + char *key_fld, + char *parent_key_fld, + char *orderby_fld, + char *branch_delim, + char *start_with, + int max_depth, + bool show_branch, + bool show_serial, + MemoryContext per_query_ctx, + bool randomAccess, + AttInMetadata *attinmeta) +{ + Tuplestorestate *tupstore = NULL; + int ret; + MemoryContext oldcontext; + + int serial = 1; + + /* Connect to SPI manager */ + if ((ret = SPI_connect()) < 0) + /* internal error */ + elog(ERROR, "connectby: SPI_connect returned %d", ret); + + /* switch to longer term context to create the tuple store */ + oldcontext = MemoryContextSwitchTo(per_query_ctx); + + /* initialize our tuplestore */ + tupstore = tuplestore_begin_heap(randomAccess, false, work_mem); + + MemoryContextSwitchTo(oldcontext); + + /* now go get the whole tree */ + build_tuplestore_recursively(key_fld, + parent_key_fld, + relname, + orderby_fld, + branch_delim, + start_with, + start_with, /* current_branch */ + 0, /* initial level is 0 */ + &serial, /* initial serial is 1 */ + max_depth, + show_branch, + show_serial, + per_query_ctx, + attinmeta, + tupstore); + + SPI_finish(); + + return tupstore; +} + +static void +build_tuplestore_recursively(char *key_fld, + char *parent_key_fld, + char *relname, + char *orderby_fld, + char *branch_delim, + char *start_with, + char *branch, + int level, + int *serial, + int max_depth, + bool show_branch, + bool show_serial, + MemoryContext per_query_ctx, + AttInMetadata *attinmeta, + Tuplestorestate *tupstore) +{ + TupleDesc tupdesc = attinmeta->tupdesc; + int ret; + uint64 proc; + int serial_column; + StringInfoData sql; + char **values; + char *current_key; + char *current_key_parent; + char current_level[INT32_STRLEN]; + char serial_str[INT32_STRLEN]; + char *current_branch; + HeapTuple tuple; + + if (max_depth > 0 && level > max_depth) + return; + + initStringInfo(&sql); + + /* Build initial sql statement */ + if (!show_serial) + { + appendStringInfo(&sql, "SELECT %s, %s FROM %s WHERE %s = %s AND %s IS NOT NULL AND %s <> %s", + key_fld, + parent_key_fld, + relname, + parent_key_fld, + quote_literal_cstr(start_with), + key_fld, key_fld, parent_key_fld); + serial_column = 0; + } + else + { + appendStringInfo(&sql, "SELECT %s, %s FROM %s WHERE %s = %s AND %s IS NOT NULL AND %s <> %s ORDER BY %s", + key_fld, + parent_key_fld, + relname, + parent_key_fld, + quote_literal_cstr(start_with), + key_fld, key_fld, parent_key_fld, + orderby_fld); + serial_column = 1; + } + + if (show_branch) + values = (char **) palloc((CONNECTBY_NCOLS + serial_column) * sizeof(char *)); + else + values = (char **) palloc((CONNECTBY_NCOLS_NOBRANCH + serial_column) * sizeof(char *)); + + /* First time through, do a little setup */ + if (level == 0) + { + /* root value is the one we initially start with */ + values[0] = start_with; + + /* root value has no parent */ + values[1] = NULL; + + /* root level is 0 */ + sprintf(current_level, "%d", level); + values[2] = current_level; + + /* root branch is just starting root value */ + if (show_branch) + values[3] = start_with; + + /* root starts the serial with 1 */ + if (show_serial) + { + sprintf(serial_str, "%d", (*serial)++); + if (show_branch) + values[4] = serial_str; + else + values[3] = serial_str; + } + + /* construct the tuple */ + tuple = BuildTupleFromCStrings(attinmeta, values); + + /* now store it */ + tuplestore_puttuple(tupstore, tuple); + + /* increment level */ + level++; + } + + /* Retrieve the desired rows */ + ret = SPI_execute(sql.data, true, 0); + proc = SPI_processed; + + /* Check for qualifying tuples */ + if ((ret == SPI_OK_SELECT) && (proc > 0)) + { + HeapTuple spi_tuple; + SPITupleTable *tuptable = SPI_tuptable; + TupleDesc spi_tupdesc = tuptable->tupdesc; + uint64 i; + StringInfoData branchstr; + StringInfoData chk_branchstr; + StringInfoData chk_current_key; + + /* + * Check that return tupdesc is compatible with the one we got from + * the query. + */ + compatConnectbyTupleDescs(tupdesc, spi_tupdesc); + + initStringInfo(&branchstr); + initStringInfo(&chk_branchstr); + initStringInfo(&chk_current_key); + + for (i = 0; i < proc; i++) + { + /* initialize branch for this pass */ + appendStringInfoString(&branchstr, branch); + appendStringInfo(&chk_branchstr, "%s%s%s", branch_delim, branch, branch_delim); + + /* get the next sql result tuple */ + spi_tuple = tuptable->vals[i]; + + /* get the current key (might be NULL) */ + current_key = SPI_getvalue(spi_tuple, spi_tupdesc, 1); + + /* get the parent key (might be NULL) */ + current_key_parent = SPI_getvalue(spi_tuple, spi_tupdesc, 2); + + /* get the current level */ + sprintf(current_level, "%d", level); + + /* check to see if this key is also an ancestor */ + if (current_key) + { + appendStringInfo(&chk_current_key, "%s%s%s", + branch_delim, current_key, branch_delim); + if (strstr(chk_branchstr.data, chk_current_key.data)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_RECURSION), + errmsg("infinite recursion detected"))); + } + + /* OK, extend the branch */ + if (current_key) + appendStringInfo(&branchstr, "%s%s", branch_delim, current_key); + current_branch = branchstr.data; + + /* build a tuple */ + values[0] = current_key; + values[1] = current_key_parent; + values[2] = current_level; + if (show_branch) + values[3] = current_branch; + if (show_serial) + { + sprintf(serial_str, "%d", (*serial)++); + if (show_branch) + values[4] = serial_str; + else + values[3] = serial_str; + } + + tuple = BuildTupleFromCStrings(attinmeta, values); + + /* store the tuple for later use */ + tuplestore_puttuple(tupstore, tuple); + + heap_freetuple(tuple); + + /* recurse using current_key as the new start_with */ + if (current_key) + build_tuplestore_recursively(key_fld, + parent_key_fld, + relname, + orderby_fld, + branch_delim, + current_key, + current_branch, + level + 1, + serial, + max_depth, + show_branch, + show_serial, + per_query_ctx, + attinmeta, + tupstore); + + xpfree(current_key); + xpfree(current_key_parent); + + /* reset branch for next pass */ + resetStringInfo(&branchstr); + resetStringInfo(&chk_branchstr); + resetStringInfo(&chk_current_key); + } + + xpfree(branchstr.data); + xpfree(chk_branchstr.data); + xpfree(chk_current_key.data); + } +} + +/* + * Check expected (query runtime) tupdesc suitable for Connectby + */ +static void +validateConnectbyTupleDesc(TupleDesc td, bool show_branch, bool show_serial) +{ + int serial_column = 0; + + if (show_serial) + serial_column = 1; + + /* are there the correct number of columns */ + if (show_branch) + { + if (td->natts != (CONNECTBY_NCOLS + serial_column)) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("Query-specified return tuple has " \ + "wrong number of columns."))); + } + else + { + if (td->natts != CONNECTBY_NCOLS_NOBRANCH + serial_column) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("Query-specified return tuple has " \ + "wrong number of columns."))); + } + + /* check that the types of the first two columns match */ + if (TupleDescAttr(td, 0)->atttypid != TupleDescAttr(td, 1)->atttypid) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("First two columns must be the same type."))); + + /* check that the type of the third column is INT4 */ + if (TupleDescAttr(td, 2)->atttypid != INT4OID) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("Third column must be type %s.", + format_type_be(INT4OID)))); + + /* check that the type of the fourth column is TEXT if applicable */ + if (show_branch && TupleDescAttr(td, 3)->atttypid != TEXTOID) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("Fourth column must be type %s.", + format_type_be(TEXTOID)))); + + /* check that the type of the fifth column is INT4 */ + if (show_branch && show_serial && + TupleDescAttr(td, 4)->atttypid != INT4OID) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("query-specified return tuple not valid for Connectby: " + "fifth column must be type %s", + format_type_be(INT4OID)))); + + /* check that the type of the fifth column is INT4 */ + if (!show_branch && show_serial && + TupleDescAttr(td, 3)->atttypid != INT4OID) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("query-specified return tuple not valid for Connectby: " + "fourth column must be type %s", + format_type_be(INT4OID)))); + + /* OK, the tupdesc is valid for our purposes */ +} + +/* + * Check if spi sql tupdesc and return tupdesc are compatible + */ +static void +compatConnectbyTupleDescs(TupleDesc ret_tupdesc, TupleDesc sql_tupdesc) +{ + Oid ret_atttypid; + Oid sql_atttypid; + int32 ret_atttypmod; + int32 sql_atttypmod; + + /* + * Result must have at least 2 columns. + */ + if (sql_tupdesc->natts < 2) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("Query must return at least two columns."))); + + /* + * These columns must match the result type indicated by the calling + * query. + */ + ret_atttypid = TupleDescAttr(ret_tupdesc, 0)->atttypid; + sql_atttypid = TupleDescAttr(sql_tupdesc, 0)->atttypid; + ret_atttypmod = TupleDescAttr(ret_tupdesc, 0)->atttypmod; + sql_atttypmod = TupleDescAttr(sql_tupdesc, 0)->atttypmod; + if (ret_atttypid != sql_atttypid || + (ret_atttypmod >= 0 && ret_atttypmod != sql_atttypmod)) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("SQL key field type %s does " \ + "not match return key field type %s.", + format_type_with_typemod(ret_atttypid, ret_atttypmod), + format_type_with_typemod(sql_atttypid, sql_atttypmod)))); + + ret_atttypid = TupleDescAttr(ret_tupdesc, 1)->atttypid; + sql_atttypid = TupleDescAttr(sql_tupdesc, 1)->atttypid; + ret_atttypmod = TupleDescAttr(ret_tupdesc, 1)->atttypmod; + sql_atttypmod = TupleDescAttr(sql_tupdesc, 1)->atttypmod; + if (ret_atttypid != sql_atttypid || + (ret_atttypmod >= 0 && ret_atttypmod != sql_atttypmod)) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("SQL parent key field type %s does " \ + "not match return parent key field type %s.", + format_type_with_typemod(ret_atttypid, ret_atttypmod), + format_type_with_typemod(sql_atttypid, sql_atttypmod)))); + + /* OK, the two tupdescs are compatible for our purposes */ +} + +/* + * Check if two tupdescs match in type of attributes + */ +static bool +compatCrosstabTupleDescs(TupleDesc ret_tupdesc, TupleDesc sql_tupdesc) +{ + int i; + Form_pg_attribute ret_attr; + Oid ret_atttypid; + Form_pg_attribute sql_attr; + Oid sql_atttypid; + + if (ret_tupdesc->natts < 2 || + sql_tupdesc->natts < 3) + return false; + + /* check the rowid types match */ + ret_atttypid = TupleDescAttr(ret_tupdesc, 0)->atttypid; + sql_atttypid = TupleDescAttr(sql_tupdesc, 0)->atttypid; + if (ret_atttypid != sql_atttypid) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("invalid return type"), + errdetail("SQL rowid datatype does not match " \ + "return rowid datatype."))); + + /* + * - attribute [1] of the sql tuple is the category; no need to check it - + * attribute [2] of the sql tuple should match attributes [1] to [natts] + * of the return tuple + */ + sql_attr = TupleDescAttr(sql_tupdesc, 2); + for (i = 1; i < ret_tupdesc->natts; i++) + { + ret_attr = TupleDescAttr(ret_tupdesc, i); + + if (ret_attr->atttypid != sql_attr->atttypid) + return false; + } + + /* OK, the two tupdescs are compatible for our purposes */ + return true; +} |