Datum textne(PG_FUNCTION_ARGS) { Datum arg1 = PG_GETARG_DATUM(0); Datum arg2 = PG_GETARG_DATUM(1); bool result; Size len1, len2; /* See comment in texteq() */ len1 = toast_raw_datum_size(arg1); len2 = toast_raw_datum_size(arg2); if (len1 != len2) result = true; else { text *targ1 = DatumGetTextPP(arg1); text *targ2 = DatumGetTextPP(arg2); result = (memcmp(VARDATA_ANY(targ1), VARDATA_ANY(targ2), len1 - VARHDRSZ) != 0); PG_FREE_IF_COPY(targ1, 0); PG_FREE_IF_COPY(targ2, 1); } PG_RETURN_BOOL(result); }
Datum texteq(PG_FUNCTION_ARGS) { Datum arg1 = PG_GETARG_DATUM(0); Datum arg2 = PG_GETARG_DATUM(1); bool result; Size len1, len2; /* * Since we only care about equality or not-equality, we can avoid all the * expense of strcoll() here, and just do bitwise comparison. In fact, we * don't even have to do a bitwise comparison if we can show the lengths * of the strings are unequal; which might save us from having to detoast * one or both values. */ len1 = toast_raw_datum_size(arg1); len2 = toast_raw_datum_size(arg2); if (len1 != len2) result = false; else { text *targ1 = DatumGetTextPP(arg1); text *targ2 = DatumGetTextPP(arg2); result = (memcmp(VARDATA_ANY(targ1), VARDATA_ANY(targ2), len1 - VARHDRSZ) == 0); PG_FREE_IF_COPY(targ1, 0); PG_FREE_IF_COPY(targ2, 1); } PG_RETURN_BOOL(result); }
/* * record_image_eq : * compares two records for identical contents, based on byte images * result : * returns true if the records are identical, false otherwise. * * Note: we do not use record_image_cmp here, since we can avoid * de-toasting for unequal lengths this way. */ Datum record_image_eq(PG_FUNCTION_ARGS) { HeapTupleHeader record1 = PG_GETARG_HEAPTUPLEHEADER(0); HeapTupleHeader record2 = PG_GETARG_HEAPTUPLEHEADER(1); bool result = true; Oid tupType1; Oid tupType2; int32 tupTypmod1; int32 tupTypmod2; TupleDesc tupdesc1; TupleDesc tupdesc2; HeapTupleData tuple1; HeapTupleData tuple2; int ncolumns1; int ncolumns2; RecordCompareData *my_extra; int ncols; Datum *values1; Datum *values2; bool *nulls1; bool *nulls2; int i1; int i2; int j; /* Extract type info from the tuples */ tupType1 = HeapTupleHeaderGetTypeId(record1); tupTypmod1 = HeapTupleHeaderGetTypMod(record1); tupdesc1 = lookup_rowtype_tupdesc(tupType1, tupTypmod1); ncolumns1 = tupdesc1->natts; tupType2 = HeapTupleHeaderGetTypeId(record2); tupTypmod2 = HeapTupleHeaderGetTypMod(record2); tupdesc2 = lookup_rowtype_tupdesc(tupType2, tupTypmod2); ncolumns2 = tupdesc2->natts; /* Build temporary HeapTuple control structures */ tuple1.t_len = HeapTupleHeaderGetDatumLength(record1); ItemPointerSetInvalid(&(tuple1.t_self)); tuple1.t_tableOid = InvalidOid; tuple1.t_data = record1; tuple2.t_len = HeapTupleHeaderGetDatumLength(record2); ItemPointerSetInvalid(&(tuple2.t_self)); tuple2.t_tableOid = InvalidOid; tuple2.t_data = record2; /* * We arrange to look up the needed comparison info just once per series * of calls, assuming the record types don't change underneath us. */ ncols = Max(ncolumns1, ncolumns2); my_extra = (RecordCompareData *) fcinfo->flinfo->fn_extra; if (my_extra == NULL || my_extra->ncolumns < ncols) { fcinfo->flinfo->fn_extra = MemoryContextAlloc(fcinfo->flinfo->fn_mcxt, offsetof(RecordCompareData, columns) + ncols * sizeof(ColumnCompareData)); my_extra = (RecordCompareData *) fcinfo->flinfo->fn_extra; my_extra->ncolumns = ncols; my_extra->record1_type = InvalidOid; my_extra->record1_typmod = 0; my_extra->record2_type = InvalidOid; my_extra->record2_typmod = 0; } if (my_extra->record1_type != tupType1 || my_extra->record1_typmod != tupTypmod1 || my_extra->record2_type != tupType2 || my_extra->record2_typmod != tupTypmod2) { MemSet(my_extra->columns, 0, ncols * sizeof(ColumnCompareData)); my_extra->record1_type = tupType1; my_extra->record1_typmod = tupTypmod1; my_extra->record2_type = tupType2; my_extra->record2_typmod = tupTypmod2; } /* Break down the tuples into fields */ values1 = (Datum *) palloc(ncolumns1 * sizeof(Datum)); nulls1 = (bool *) palloc(ncolumns1 * sizeof(bool)); heap_deform_tuple(&tuple1, tupdesc1, values1, nulls1); values2 = (Datum *) palloc(ncolumns2 * sizeof(Datum)); nulls2 = (bool *) palloc(ncolumns2 * sizeof(bool)); heap_deform_tuple(&tuple2, tupdesc2, values2, nulls2); /* * Scan corresponding columns, allowing for dropped columns in different * places in the two rows. i1 and i2 are physical column indexes, j is * the logical column index. */ i1 = i2 = j = 0; while (i1 < ncolumns1 || i2 < ncolumns2) { /* * Skip dropped columns */ if (i1 < ncolumns1 && tupdesc1->attrs[i1]->attisdropped) { i1++; continue; } if (i2 < ncolumns2 && tupdesc2->attrs[i2]->attisdropped) { i2++; continue; } if (i1 >= ncolumns1 || i2 >= ncolumns2) break; /* we'll deal with mismatch below loop */ /* * Have two matching columns, they must be same type */ if (tupdesc1->attrs[i1]->atttypid != tupdesc2->attrs[i2]->atttypid) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("cannot compare dissimilar column types %s and %s at record column %d", format_type_be(tupdesc1->attrs[i1]->atttypid), format_type_be(tupdesc2->attrs[i2]->atttypid), j + 1))); /* * We consider two NULLs equal; NULL > not-NULL. */ if (!nulls1[i1] || !nulls2[i2]) { if (nulls1[i1] || nulls2[i2]) { result = false; break; } /* Compare the pair of elements */ if (tupdesc1->attrs[i1]->attlen == -1) { Size len1, len2; len1 = toast_raw_datum_size(values1[i1]); len2 = toast_raw_datum_size(values2[i2]); /* No need to de-toast if lengths don't match. */ if (len1 != len2) result = false; else { struct varlena *arg1val; struct varlena *arg2val; arg1val = PG_DETOAST_DATUM_PACKED(values1[i1]); arg2val = PG_DETOAST_DATUM_PACKED(values2[i2]); result = (memcmp(VARDATA_ANY(arg1val), VARDATA_ANY(arg2val), len1 - VARHDRSZ) == 0); /* Only free memory if it's a copy made here. */ if ((Pointer) arg1val != (Pointer) values1[i1]) pfree(arg1val); if ((Pointer) arg2val != (Pointer) values2[i2]) pfree(arg2val); } } else if (tupdesc1->attrs[i1]->attbyval) { switch (tupdesc1->attrs[i1]->attlen) { case 1: result = (GET_1_BYTE(values1[i1]) == GET_1_BYTE(values2[i2])); break; case 2: result = (GET_2_BYTES(values1[i1]) == GET_2_BYTES(values2[i2])); break; case 4: result = (GET_4_BYTES(values1[i1]) == GET_4_BYTES(values2[i2])); break; #if SIZEOF_DATUM == 8 case 8: result = (GET_8_BYTES(values1[i1]) == GET_8_BYTES(values2[i2])); break; #endif default: Assert(false); /* cannot happen */ } } else { result = (memcmp(DatumGetPointer(values1[i1]), DatumGetPointer(values2[i2]), tupdesc1->attrs[i1]->attlen) == 0); } if (!result) break; } /* equal, so continue to next column */ i1++, i2++, j++; } /* * If we didn't break out of the loop early, check for column count * mismatch. (We do not report such mismatch if we found unequal column * values; is that a feature or a bug?) */ if (result) { if (i1 != ncolumns1 || i2 != ncolumns2) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("cannot compare record types with different numbers of columns"))); } pfree(values1); pfree(nulls1); pfree(values2); pfree(nulls2); ReleaseTupleDesc(tupdesc1); ReleaseTupleDesc(tupdesc2); /* Avoid leaking memory when handed toasted input. */ PG_FREE_IF_COPY(record1, 0); PG_FREE_IF_COPY(record2, 1); PG_RETURN_BOOL(result); }
/* * compute_array_stats() -- compute statistics for an array column * * This function computes statistics useful for determining selectivity of * the array operators <@, &&, and @>. It is invoked by ANALYZE via the * compute_stats hook after sample rows have been collected. * * We also invoke the standard compute_stats function, which will compute * "scalar" statistics relevant to the btree-style array comparison operators. * However, exact duplicates of an entire array may be rare despite many * arrays sharing individual elements. This especially afflicts long arrays, * which are also liable to lack all scalar statistics due to the low * WIDTH_THRESHOLD used in analyze.c. So, in addition to the standard stats, * we find the most common array elements and compute a histogram of distinct * element counts. * * The algorithm used is Lossy Counting, as proposed in the paper "Approximate * frequency counts over data streams" by G. S. Manku and R. Motwani, in * Proceedings of the 28th International Conference on Very Large Data Bases, * Hong Kong, China, August 2002, section 4.2. The paper is available at * http://www.vldb.org/conf/2002/S10P03.pdf * * The Lossy Counting (aka LC) algorithm goes like this: * Let s be the threshold frequency for an item (the minimum frequency we * are interested in) and epsilon the error margin for the frequency. Let D * be a set of triples (e, f, delta), where e is an element value, f is that * element's frequency (actually, its current occurrence count) and delta is * the maximum error in f. We start with D empty and process the elements in * batches of size w. (The batch size is also known as "bucket size" and is * equal to 1/epsilon.) Let the current batch number be b_current, starting * with 1. For each element e we either increment its f count, if it's * already in D, or insert a new___ triple into D with values (e, 1, b_current * - 1). After processing each batch we prune D, by removing from it all * elements with f + delta <= b_current. After the algorithm finishes we * suppress all elements from D that do not satisfy f >= (s - epsilon) * N, * where N is the total number of elements in the input. We emit the * remaining elements with estimated frequency f/N. The LC paper proves * that this algorithm finds all elements with true frequency at least s, * and that no frequency is overestimated or is underestimated by more than * epsilon. Furthermore, given reasonable assumptions about the input * distribution, the required table size is no more than about 7 times w. * * In the absence of a principled basis for other particular values, we * follow ts_typanalyze() and use parameters s = 0.07/K, epsilon = s/10. * But we leave out the correction for stopwords, which do not apply to * arrays. These parameters give bucket width w = K/0.007 and maximum * expected hashtable size of about 1000 * K. * * Elements may repeat within an array. Since duplicates do not change the * behavior of <@, && or @>, we want to count each element only once per * array. Therefore, we store in the finished pg_statistic entry each * element's frequency as the fraction of all non-null rows that contain it. * We divide the raw counts by nonnull_cnt to get those figures. */ static void compute_array_stats(VacAttrStats *stats, AnalyzeAttrFetchFunc fetchfunc, int samplerows, double totalrows) { ArrayAnalyzeExtraData *extra_data; int num_mcelem; int null_cnt = 0; int null_elem_cnt = 0; int analyzed_rows = 0; /* This is D from the LC algorithm. */ HTAB *elements_tab; HASHCTL elem_hash_ctl; HASH_SEQ_STATUS scan_status; /* This is the current bucket number from the LC algorithm */ int b_current; /* This is 'w' from the LC algorithm */ int bucket_width; int array_no; int64 element_no; TrackItem *item; int slot_idx; HTAB *count_tab; HASHCTL count_hash_ctl; DECountItem *count_item; extra_data = (ArrayAnalyzeExtraData *) stats->extra_data; /* * Invoke analyze.c's standard analysis function to create scalar-style * stats for the column. It will expect its own extra_data pointer, so * temporarily install that. */ stats->extra_data = extra_data->std_extra_data; (*extra_data->std_compute_stats) (stats, fetchfunc, samplerows, totalrows); stats->extra_data = extra_data; /* * Set up static pointer for use by subroutines. We wait till here in * case std_compute_stats somehow recursively invokes us (probably not * possible, but ...) */ array_extra_data = extra_data; /* * We want statistics_target * 10 elements in the MCELEM array. This * multiplier is pretty arbitrary, but is meant to reflect the fact that * the number of individual elements tracked in pg_statistic ought to be * more than the number of values for a simple scalar column. */ num_mcelem = stats->attr->attstattarget * 10; /* * We set bucket width equal to num_mcelem / 0.007 as per the comment * above. */ bucket_width = num_mcelem * 1000 / 7; /* * Create the hashtable. It will be in local memory, so we don't need to * worry about overflowing the initial size. Also we don't need to pay any * attention to locking and memory management. */ MemSet(&elem_hash_ctl, 0, sizeof(elem_hash_ctl)); elem_hash_ctl.keysize = sizeof(Datum); elem_hash_ctl.entrysize = sizeof(TrackItem); elem_hash_ctl.hash = element_hash; elem_hash_ctl.match = element_match; elem_hash_ctl.hcxt = CurrentMemoryContext; elements_tab = hash_create("Analyzed elements table", num_mcelem, &elem_hash_ctl, HASH_ELEM | HASH_FUNCTION | HASH_COMPARE | HASH_CONTEXT); /* hashtable for array distinct elements counts */ MemSet(&count_hash_ctl, 0, sizeof(count_hash_ctl)); count_hash_ctl.keysize = sizeof(int); count_hash_ctl.entrysize = sizeof(DECountItem); count_hash_ctl.hcxt = CurrentMemoryContext; count_tab = hash_create("Array distinct element count table", 64, &count_hash_ctl, HASH_ELEM | HASH_BLOBS | HASH_CONTEXT); /* Initialize counters. */ b_current = 1; element_no = 0; /* Loop over the arrays. */ for (array_no = 0; array_no < samplerows; array_no++) { Datum value; bool isnull; ArrayType *array; int num_elems; Datum *elem_values; bool *elem_nulls; bool null_present; int j; int64 prev_element_no = element_no; int distinct_count; bool count_item_found; vacuum_delay_point(); value = fetchfunc(stats, array_no, &isnull); if (isnull) { /* array is null, just count that */ null_cnt++; continue; } /* Skip too-large values. */ if (toast_raw_datum_size(value) > ARRAY_WIDTH_THRESHOLD) continue; else analyzed_rows++; /* * Now detoast the array if needed, and deconstruct into datums. */ array = DatumGetArrayTypeP(value); Assert(ARR_ELEMTYPE(array) == extra_data->type_id); deconstruct_array(array, extra_data->type_id, extra_data->typlen, extra_data->typbyval, extra_data->typalign, &elem_values, &elem_nulls, &num_elems); /* * We loop through the elements in the array and add them to our * tracking hashtable. */ null_present = false; for (j = 0; j < num_elems; j++) { Datum elem_value; bool found; /* No null element processing other than flag setting here */ if (elem_nulls[j]) { null_present = true; continue; } /* Lookup current element in hashtable, adding it if new___ */ elem_value = elem_values[j]; item = (TrackItem *) hash_search(elements_tab, (const void *) &elem_value, HASH_ENTER, &found); if (found) { /* The element value is already on the tracking list */ /* * The operators we assist ignore duplicate array elements, so * count a given distinct element only once per array. */ if (item->last_container == array_no) continue; item->frequency++; item->last_container = array_no; } else { /* Initialize new___ tracking list element */ /* * If element type is pass-by-reference, we must copy it into * palloc'd space, so that we can release the array below. (We * do this so that the space needed for element values is * limited by the size of the hashtable; if we kept all the * array values around, it could be much more.) */ item->key = datumCopy(elem_value, extra_data->typbyval, extra_data->typlen); item->frequency = 1; item->delta = b_current - 1; item->last_container = array_no; } /* element_no is the number of elements processed (ie N) */ element_no++; /* We prune the D structure after processing each bucket */ if (element_no % bucket_width == 0) { prune_element_hashtable(elements_tab, b_current); b_current++; } } /* Count null element presence once per array. */ if (null_present) null_elem_cnt++; /* Update frequency of the particular array distinct element count. */ distinct_count = (int) (element_no - prev_element_no); count_item = (DECountItem *) hash_search(count_tab, &distinct_count, HASH_ENTER, &count_item_found); if (count_item_found) count_item->frequency++; else count_item->frequency = 1; /* Free memory allocated while detoasting. */ if (PointerGetDatum(array) != value) pfree(array); pfree(elem_values); pfree(elem_nulls); } /* Skip pg_statistic slots occupied by standard statistics */ slot_idx = 0; while (slot_idx < STATISTIC_NUM_SLOTS && stats->stakind[slot_idx] != 0) slot_idx++; if (slot_idx > STATISTIC_NUM_SLOTS - 2) elog(ERROR, "insufficient pg_statistic slots for array stats"); /* We can only compute real stats if we found some non-null values. */ if (analyzed_rows > 0) { int nonnull_cnt = analyzed_rows; int count_items_count; int i; TrackItem **sort_table; int track_len; int64 cutoff_freq; int64 minfreq, maxfreq; /* * We assume the standard stats code already took care of setting * stats_valid, stanullfrac, stawidth, stadistinct. We'd have to * re-compute those values if we wanted to not store the standard * stats. */ /* * Construct an array of the interesting hashtable items, that is, * those meeting the cutoff frequency (s - epsilon)*N. Also identify * the minimum and maximum frequencies among these items. * * Since epsilon = s/10 and bucket_width = 1/epsilon, the cutoff * frequency is 9*N / bucket_width. */ cutoff_freq = 9 * element_no / bucket_width; i = hash_get_num_entries(elements_tab); /* surely enough space */ sort_table = (TrackItem **) palloc(sizeof(TrackItem *) * i); hash_seq_init(&scan_status, elements_tab); track_len = 0; minfreq = element_no; maxfreq = 0; while ((item = (TrackItem *) hash_seq_search(&scan_status)) != NULL) { if (item->frequency > cutoff_freq) { sort_table[track_len++] = item; minfreq = Min(minfreq, item->frequency); maxfreq = Max(maxfreq, item->frequency); } } Assert(track_len <= i); /* emit some statistics for debug purposes */ elog(DEBUG3, "compute_array_stats: target # mces = %d, " "bucket width = %d, " "# elements = " INT64_FORMAT ", hashtable size = %d, " "usable entries = %d", num_mcelem, bucket_width, element_no, i, track_len); /* * If we obtained more elements than we really want, get rid of those * with least frequencies. The easiest way is to qsort the array into * descending frequency order and truncate the array. */ if (num_mcelem < track_len) { qsort(sort_table, track_len, sizeof(TrackItem *), trackitem_compare_frequencies_desc); /* reset minfreq to the smallest frequency we're keeping */ minfreq = sort_table[num_mcelem - 1]->frequency; } else num_mcelem = track_len; /* Generate MCELEM slot entry */ if (num_mcelem > 0) { MemoryContext old_context; Datum *mcelem_values; float4 *mcelem_freqs; /* * We want to store statistics sorted on the element value using * the element type's default comparison function. This permits * fast binary searches in selectivity estimation functions. */ qsort(sort_table, num_mcelem, sizeof(TrackItem *), trackitem_compare_element); /* Must copy the target values into anl_context */ old_context = MemoryContextSwitchTo(stats->anl_context); /* * We sorted statistics on the element value, but we want to be * able to find the minimal and maximal frequencies without going * through all the values. We also want the frequency of null * elements. Store these three values at the end of mcelem_freqs. */ mcelem_values = (Datum *) palloc(num_mcelem * sizeof(Datum)); mcelem_freqs = (float4 *) palloc((num_mcelem + 3) * sizeof(float4)); /* * See comments above about use of nonnull_cnt as the divisor for * the final frequency estimates. */ for (i = 0; i < num_mcelem; i++) { TrackItem *item = sort_table[i]; mcelem_values[i] = datumCopy(item->key, extra_data->typbyval, extra_data->typlen); mcelem_freqs[i] = (double) item->frequency / (double) nonnull_cnt; } mcelem_freqs[i++] = (double) minfreq / (double) nonnull_cnt; mcelem_freqs[i++] = (double) maxfreq / (double) nonnull_cnt; mcelem_freqs[i++] = (double) null_elem_cnt / (double) nonnull_cnt; MemoryContextSwitchTo(old_context); stats->stakind[slot_idx] = STATISTIC_KIND_MCELEM; stats->staop[slot_idx] = extra_data->eq_opr; stats->stanumbers[slot_idx] = mcelem_freqs; /* See above comment about extra stanumber entries */ stats->numnumbers[slot_idx] = num_mcelem + 3; stats->stavalues[slot_idx] = mcelem_values; stats->numvalues[slot_idx] = num_mcelem; /* We are storing values of element type */ stats->statypid[slot_idx] = extra_data->type_id; stats->statyplen[slot_idx] = extra_data->typlen; stats->statypbyval[slot_idx] = extra_data->typbyval; stats->statypalign[slot_idx] = extra_data->typalign; slot_idx++; } /* Generate DECHIST slot entry */ count_items_count = hash_get_num_entries(count_tab); if (count_items_count > 0) { int num_hist = stats->attr->attstattarget; DECountItem **sorted_count_items; int j; int delta; int64 frac; float4 *hist; /* num_hist must be at least 2 for the loop below to work */ num_hist = Max(num_hist, 2); /* * Create an array of DECountItem pointers, and sort them into * increasing count order. */ sorted_count_items = (DECountItem **) palloc(sizeof(DECountItem *) * count_items_count); hash_seq_init(&scan_status, count_tab); j = 0; while ((count_item = (DECountItem *) hash_seq_search(&scan_status)) != NULL) { sorted_count_items[j++] = count_item; } qsort(sorted_count_items, count_items_count, sizeof(DECountItem *), countitem_compare_count); /* * Prepare to fill stanumbers with the histogram, followed by the * average count. This array must be stored in anl_context. */ hist = (float4 *) MemoryContextAlloc(stats->anl_context, sizeof(float4) * (num_hist + 1)); hist[num_hist] = (double) element_no / (double) nonnull_cnt; /*---------- * Construct the histogram of distinct-element counts (DECs). * * The object of this loop is to copy the min and max DECs to * hist[0] and hist[num_hist - 1], along with evenly-spaced DECs * in between (where "evenly-spaced" is with reference to the * whole input population of arrays). If we had a complete sorted * array of DECs, one per analyzed row, the i'th hist value would * come from DECs[i * (analyzed_rows - 1) / (num_hist - 1)] * (compare the histogram-making loop in compute_scalar_stats()). * But instead of that we have the sorted_count_items[] array, * which holds unique DEC values with their frequencies (that is, * a run-length-compressed version of the full array). So we * control advancing through sorted_count_items[] with the * variable "frac", which is defined as (x - y) * (num_hist - 1), * where x is the index in the notional DECs array corresponding * to the start of the next sorted_count_items[] element's run, * and y is the index in DECs from which we should take the next * histogram value. We have to advance whenever x <= y, that is * frac <= 0. The x component is the sum of the frequencies seen * so far (up through the current sorted_count_items[] element), * and of course y * (num_hist - 1) = i * (analyzed_rows - 1), * per the subscript calculation above. (The subscript calculation * implies dropping any fractional part of y; in this formulation * that's handled by not advancing until frac reaches 1.) * * Even though frac has a bounded range, it could overflow int32 * when working with very large statistics targets, so we do that * math in int64. *---------- */ delta = analyzed_rows - 1; j = 0; /* current index in sorted_count_items */ /* Initialize frac for sorted_count_items[0]; y is initially 0 */ frac = (int64) sorted_count_items[0]->frequency * (num_hist - 1); for (i = 0; i < num_hist; i++) { while (frac <= 0) { /* Advance, and update x component of frac */ j++; frac += (int64) sorted_count_items[j]->frequency * (num_hist - 1); } hist[i] = sorted_count_items[j]->count; frac -= delta; /* update y for upcoming i increment */ } Assert(j == count_items_count - 1); stats->stakind[slot_idx] = STATISTIC_KIND_DECHIST; stats->staop[slot_idx] = extra_data->eq_opr; stats->stanumbers[slot_idx] = hist; stats->numnumbers[slot_idx] = num_hist + 1; slot_idx++; } } /* * We don't need to bother cleaning up any of our temporary palloc's. The * hashtable should also go away, as it used a child memory context. */ }