aboutsummaryrefslogtreecommitdiff
path: root/src
diff options
context:
space:
mode:
Diffstat (limited to 'src')
-rw-r--r--src/backend/statistics/mcv.c116
-rw-r--r--src/include/catalog/catversion.h2
2 files changed, 78 insertions, 40 deletions
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index d1af5d84d00..2daefb26868 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -61,6 +61,16 @@
#define ITEM_FREQUENCY(item,ndims) ((double *) (ITEM_NULLS(item, ndims) + (ndims)))
#define ITEM_BASE_FREQUENCY(item,ndims) ((double *) (ITEM_FREQUENCY(item, ndims) + 1))
+/*
+ * Used to compute size of serialized MCV list representation.
+ */
+#define MinSizeOfMCVList \
+ (VARHDRSZ + sizeof(uint32) * 3 + sizeof(AttrNumber))
+
+#define SizeOfMCVList(ndims,nitems) \
+ (MAXALIGN(MinSizeOfMCVList + sizeof(Oid) * (ndims)) + \
+ MAXALIGN((ndims) * sizeof(DimensionInfo)) + \
+ MAXALIGN((nitems) * ITEM_SIZE(ndims)))
static MultiSortSupport build_mss(VacAttrStats **stats, int numattrs);
@@ -491,7 +501,6 @@ statext_mcv_serialize(MCVList * mcvlist, VacAttrStats **stats)
char *item = palloc0(itemsize);
/* serialized items (indexes into arrays, etc.) */
- bytea *output;
char *raw;
char *ptr;
@@ -625,15 +634,25 @@ statext_mcv_serialize(MCVList * mcvlist, VacAttrStats **stats)
* Now we can finally compute how much space we'll actually need for the
* whole serialized MCV list (varlena header, MCV header, dimension info
* for each attribute, deduplicated values and items).
+ *
+ * The header fields are copied one by one, so that we don't need any
+ * explicit alignment (we copy them while deserializing). All fields
+ * after this need to be properly aligned, for direct access.
*/
- total_length = offsetof(MCVList, items)
- + MAXALIGN(ndims * sizeof(DimensionInfo));
+ total_length = MAXALIGN(VARHDRSZ + (3 * sizeof(uint32))
+ + sizeof(AttrNumber) + (ndims * sizeof(Oid)));
+
+ /* dimension info */
+ total_length += MAXALIGN(ndims * sizeof(DimensionInfo));
/* add space for the arrays of deduplicated values */
for (i = 0; i < ndims; i++)
total_length += MAXALIGN(info[i].nbytes);
- /* and finally the items (no additional alignment needed) */
+ /*
+ * And finally the items (no additional alignment needed, we start
+ * at proper alignment and the itemsize formula uses MAXALIGN)
+ */
total_length += mcvlist->nitems * itemsize;
/*
@@ -641,11 +660,27 @@ statext_mcv_serialize(MCVList * mcvlist, VacAttrStats **stats)
* so we set them to zero to make the result more compressible).
*/
raw = palloc0(total_length);
- ptr = raw;
+ SET_VARSIZE(raw, total_length);
+ ptr = VARDATA(raw);
+
+ /* copy the MCV list header fields, one by one */
+ memcpy(ptr, &mcvlist->magic, sizeof(uint32));
+ ptr += sizeof(uint32);
+
+ memcpy(ptr, &mcvlist->type, sizeof(uint32));
+ ptr += sizeof(uint32);
+
+ memcpy(ptr, &mcvlist->nitems, sizeof(uint32));
+ ptr += sizeof(uint32);
+
+ memcpy(ptr, &mcvlist->ndimensions, sizeof(AttrNumber));
+ ptr += sizeof(AttrNumber);
- /* copy the MCV list header */
- memcpy(ptr, mcvlist, offsetof(MCVList, items));
- ptr += offsetof(MCVList, items);
+ memcpy(ptr, mcvlist->types, sizeof(Oid) * ndims);
+ ptr += (sizeof(Oid) * ndims);
+
+ /* the header may not be exactly aligned, so make sure it is */
+ ptr = raw + MAXALIGN(ptr - raw);
/* store information about the attributes */
memcpy(ptr, info, sizeof(DimensionInfo) * ndims);
@@ -761,14 +796,7 @@ statext_mcv_serialize(MCVList * mcvlist, VacAttrStats **stats)
pfree(values);
pfree(counts);
- output = (bytea *) palloc(VARHDRSZ + total_length);
- SET_VARSIZE(output, VARHDRSZ + total_length);
-
- memcpy(VARDATA_ANY(output), raw, total_length);
-
- pfree(raw);
-
- return output;
+ return (bytea *) raw;
}
/*
@@ -789,8 +817,7 @@ statext_mcv_deserialize(bytea *data)
char *ptr;
int ndims,
- nitems,
- itemsize;
+ nitems;
DimensionInfo *info = NULL;
/* local allocation buffer (used only for deserialization) */
@@ -810,24 +837,32 @@ statext_mcv_deserialize(bytea *data)
/*
* We can't possibly deserialize a MCV list if there's not even a complete
- * header.
+ * header. We need an explicit formula here, because we serialize the
+ * header fields one by one, so we need to ignore struct alignment.
*/
- if (VARSIZE_ANY_EXHDR(data) < offsetof(MCVList, items))
+ if (VARSIZE_ANY(data) < MinSizeOfMCVList)
elog(ERROR, "invalid MCV size %zd (expected at least %zu)",
- VARSIZE_ANY_EXHDR(data), offsetof(MCVList, items));
+ VARSIZE_ANY(data), MinSizeOfMCVList);
/* read the MCV list header */
mcvlist = (MCVList *) palloc0(offsetof(MCVList, items));
- /* initialize pointer to the data part (skip the varlena header) */
- raw = palloc(VARSIZE_ANY_EXHDR(data));
- ptr = raw;
-
- memcpy(raw, VARDATA_ANY(data), VARSIZE_ANY_EXHDR(data));
+ /* pointer to the data part (skip the varlena header) */
+ ptr = VARDATA_ANY(data);
+ raw = (char *) data;
/* get the header and perform further sanity checks */
- memcpy(mcvlist, ptr, offsetof(MCVList, items));
- ptr += offsetof(MCVList, items);
+ memcpy(&mcvlist->magic, ptr, sizeof(uint32));
+ ptr += sizeof(uint32);
+
+ memcpy(&mcvlist->type, ptr, sizeof(uint32));
+ ptr += sizeof(uint32);
+
+ memcpy(&mcvlist->nitems, ptr, sizeof(uint32));
+ ptr += sizeof(uint32);
+
+ memcpy(&mcvlist->ndimensions, ptr, sizeof(AttrNumber));
+ ptr += sizeof(AttrNumber);
if (mcvlist->magic != STATS_MCV_MAGIC)
elog(ERROR, "invalid MCV magic %u (expected %u)",
@@ -852,25 +887,29 @@ statext_mcv_deserialize(bytea *data)
nitems = mcvlist->nitems;
ndims = mcvlist->ndimensions;
- itemsize = ITEM_SIZE(ndims);
/*
* Check amount of data including DimensionInfo for all dimensions and
* also the serialized items (including uint16 indexes). Also, walk
* through the dimension information and add it to the sum.
*/
- expected_size = offsetof(MCVList, items) +
- ndims * sizeof(DimensionInfo) +
- (nitems * itemsize);
+ expected_size = SizeOfMCVList(ndims, nitems);
/*
* Check that we have at least the dimension and info records, along with
* the items. We don't know the size of the serialized values yet. We need
* to do this check first, before accessing the dimension info.
*/
- if (VARSIZE_ANY_EXHDR(data) < expected_size)
+ if (VARSIZE_ANY(data) < expected_size)
elog(ERROR, "invalid MCV size %zd (expected %zu)",
- VARSIZE_ANY_EXHDR(data), expected_size);
+ VARSIZE_ANY(data), expected_size);
+
+ /* Now copy the array of type Oids. */
+ memcpy(ptr, mcvlist->types, sizeof(Oid) * ndims);
+ ptr += (sizeof(Oid) * ndims);
+
+ /* ensure alignment of the pointer (after the header fields) */
+ ptr = raw + MAXALIGN(ptr - raw);
/* Now it's safe to access the dimension info. */
info = (DimensionInfo *) ptr;
@@ -894,9 +933,9 @@ statext_mcv_deserialize(bytea *data)
* (header, dimension info. items and deduplicated data). So do the final
* check on size.
*/
- if (VARSIZE_ANY_EXHDR(data) != expected_size)
+ if (VARSIZE_ANY(data) != expected_size)
elog(ERROR, "invalid MCV size %zd (expected %zu)",
- VARSIZE_ANY_EXHDR(data), expected_size);
+ VARSIZE_ANY(data), expected_size);
/*
* We need an array of Datum values for each dimension, so that we can
@@ -1063,18 +1102,17 @@ statext_mcv_deserialize(bytea *data)
ptr += ITEM_SIZE(ndims);
/* check we're not overflowing the input */
- Assert(ptr <= (char *) raw + VARSIZE_ANY_EXHDR(data));
+ Assert(ptr <= (char *) raw + VARSIZE_ANY(data));
}
/* check that we processed all the data */
- Assert(ptr == raw + VARSIZE_ANY_EXHDR(data));
+ Assert(ptr == raw + VARSIZE_ANY(data));
/* release the buffers used for mapping */
for (dim = 0; dim < ndims; dim++)
pfree(map[dim]);
pfree(map);
- pfree(raw);
return mcvlist;
}
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 43142b67c58..1fe54c26653 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 201904021
+#define CATALOG_VERSION_NO 201904031
#endif
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-31 17:30:36 +0000