I have another little idea that fits well here: repalloc0 and
repalloc0_array. These zero out the space added by repalloc. This is a
common pattern in the backend code that is quite hairy to code by hand.
See attached patch.
From fa611ecf7c8a7b99d37c77da66b421d2f9ebfec3 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pe...@eisentraut.org>
Date: Wed, 14 Sep 2022 06:05:46 +0200
Subject: [PATCH] Add repalloc0 and repalloc0_array
These zero out the space added by repalloc. This is a common pattern
that is quite hairy to code by hand.
---
src/backend/executor/nodeHash.c | 8 ++-----
src/backend/libpq/be-fsstubs.c | 9 +++-----
src/backend/optimizer/util/placeholder.c | 13 ++++-------
src/backend/optimizer/util/relnode.c | 29 +++++++-----------------
src/backend/parser/parse_param.c | 10 +++-----
src/backend/storage/lmgr/lwlock.c | 9 ++------
src/backend/utils/adt/ruleutils.c | 9 ++------
src/backend/utils/cache/typcache.c | 10 ++------
src/backend/utils/mmgr/mcxt.c | 15 ++++++++++++
src/include/utils/palloc.h | 2 ++
10 files changed, 43 insertions(+), 71 deletions(-)
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index 77dd1dae8b..674802a4ff 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -940,12 +940,8 @@ ExecHashIncreaseNumBatches(HashJoinTable hashtable)
else
{
/* enlarge arrays and zero out added entries */
- hashtable->innerBatchFile =
repalloc_array(hashtable->innerBatchFile, BufFile *, nbatch);
- hashtable->outerBatchFile =
repalloc_array(hashtable->outerBatchFile, BufFile *, nbatch);
- MemSet(hashtable->innerBatchFile + oldnbatch, 0,
- (nbatch - oldnbatch) * sizeof(BufFile *));
- MemSet(hashtable->outerBatchFile + oldnbatch, 0,
- (nbatch - oldnbatch) * sizeof(BufFile *));
+ hashtable->innerBatchFile =
repalloc0_array(hashtable->innerBatchFile, BufFile *, nbatch, oldnbatch);
+ hashtable->outerBatchFile =
repalloc0_array(hashtable->outerBatchFile, BufFile *, nbatch, oldnbatch);
}
MemoryContextSwitchTo(oldcxt);
diff --git a/src/backend/libpq/be-fsstubs.c b/src/backend/libpq/be-fsstubs.c
index 3e5cada7eb..bf901a9cdc 100644
--- a/src/backend/libpq/be-fsstubs.c
+++ b/src/backend/libpq/be-fsstubs.c
@@ -696,19 +696,16 @@ newLOfd(void)
newsize = 64;
cookies = (LargeObjectDesc **)
MemoryContextAllocZero(fscxt, newsize *
sizeof(LargeObjectDesc *));
- cookies_size = newsize;
}
else
{
/* Double size of array */
i = cookies_size;
newsize = cookies_size * 2;
- cookies = (LargeObjectDesc **)
- repalloc(cookies, newsize * sizeof(LargeObjectDesc *));
- MemSet(cookies + cookies_size, 0,
- (newsize - cookies_size) * sizeof(LargeObjectDesc
*));
- cookies_size = newsize;
+ cookies =
+ repalloc0_array(cookies, LargeObjectDesc *, newsize,
cookies_size);
}
+ cookies_size = newsize;
return i;
}
diff --git a/src/backend/optimizer/util/placeholder.c
b/src/backend/optimizer/util/placeholder.c
index c7bfa293c9..e40b3a12fd 100644
--- a/src/backend/optimizer/util/placeholder.c
+++ b/src/backend/optimizer/util/placeholder.c
@@ -133,16 +133,11 @@ find_placeholder_info(PlannerInfo *root, PlaceHolderVar
*phv)
while (phinfo->phid >= new_size)
new_size *= 2;
if (root->placeholder_array)
- {
- root->placeholder_array = (PlaceHolderInfo **)
- repalloc(root->placeholder_array,
- sizeof(PlaceHolderInfo *) *
new_size);
- MemSet(root->placeholder_array +
root->placeholder_array_size, 0,
- sizeof(PlaceHolderInfo *) * (new_size -
root->placeholder_array_size));
- }
+ root->placeholder_array =
+ repalloc0_array(root->placeholder_array,
PlaceHolderInfo *, new_size, root->placeholder_array_size);
else
- root->placeholder_array = (PlaceHolderInfo **)
- palloc0(new_size * sizeof(PlaceHolderInfo *));
+ root->placeholder_array =
+ palloc0_array(PlaceHolderInfo *, new_size);
root->placeholder_array_size = new_size;
}
root->placeholder_array[phinfo->phid] = phinfo;
diff --git a/src/backend/optimizer/util/relnode.c
b/src/backend/optimizer/util/relnode.c
index edcdd0a360..3ea40ff1b6 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -157,31 +157,18 @@ expand_planner_arrays(PlannerInfo *root, int add_size)
new_size = root->simple_rel_array_size + add_size;
- root->simple_rel_array = (RelOptInfo **)
- repalloc(root->simple_rel_array,
- sizeof(RelOptInfo *) * new_size);
- MemSet(root->simple_rel_array + root->simple_rel_array_size,
- 0, sizeof(RelOptInfo *) * add_size);
+ root->simple_rel_array =
+ repalloc0_array(root->simple_rel_array, RelOptInfo *, new_size,
root->simple_rel_array_size);
- root->simple_rte_array = (RangeTblEntry **)
- repalloc(root->simple_rte_array,
- sizeof(RangeTblEntry *) * new_size);
- MemSet(root->simple_rte_array + root->simple_rel_array_size,
- 0, sizeof(RangeTblEntry *) * add_size);
+ root->simple_rte_array =
+ repalloc0_array(root->simple_rte_array, RangeTblEntry *,
new_size, root->simple_rel_array_size);
if (root->append_rel_array)
- {
- root->append_rel_array = (AppendRelInfo **)
- repalloc(root->append_rel_array,
- sizeof(AppendRelInfo *) * new_size);
- MemSet(root->append_rel_array + root->simple_rel_array_size,
- 0, sizeof(AppendRelInfo *) * add_size);
- }
+ root->append_rel_array =
+ repalloc0_array(root->append_rel_array, AppendRelInfo
*, new_size, root->simple_rel_array_size);
else
- {
- root->append_rel_array = (AppendRelInfo **)
- palloc0(sizeof(AppendRelInfo *) * new_size);
- }
+ root->append_rel_array =
+ palloc0_array(AppendRelInfo *, new_size);
root->simple_rel_array_size = new_size;
}
diff --git a/src/backend/parser/parse_param.c b/src/backend/parser/parse_param.c
index f668abfcb3..4efec211c5 100644
--- a/src/backend/parser/parse_param.c
+++ b/src/backend/parser/parse_param.c
@@ -145,14 +145,10 @@ variable_paramref_hook(ParseState *pstate, ParamRef *pref)
{
/* Need to enlarge param array */
if (*parstate->paramTypes)
- *parstate->paramTypes = (Oid *)
repalloc(*parstate->paramTypes,
-
paramno * sizeof(Oid));
+ *parstate->paramTypes =
repalloc0_array(*parstate->paramTypes, Oid,
+
paramno, *parstate->numParams);
else
- *parstate->paramTypes = (Oid *) palloc(paramno *
sizeof(Oid));
- /* Zero out the previously-unreferenced slots */
- MemSet(*parstate->paramTypes + *parstate->numParams,
- 0,
- (paramno - *parstate->numParams) * sizeof(Oid));
+ *parstate->paramTypes = palloc0_array(Oid, paramno);
*parstate->numParams = paramno;
}
diff --git a/src/backend/storage/lmgr/lwlock.c
b/src/backend/storage/lmgr/lwlock.c
index 38317edaf9..a36dcf1a00 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -668,13 +668,8 @@ LWLockRegisterTranche(int tranche_id, const char
*tranche_name)
MemoryContextAllocZero(TopMemoryContext,
newalloc * sizeof(char *));
else
- {
- LWLockTrancheNames = (const char **)
- repalloc(LWLockTrancheNames, newalloc *
sizeof(char *));
- memset(LWLockTrancheNames + LWLockTrancheNamesAllocated,
- 0,
- (newalloc - LWLockTrancheNamesAllocated) *
sizeof(char *));
- }
+ LWLockTrancheNames =
+ repalloc0_array(LWLockTrancheNames, const char
*, newalloc, LWLockTrancheNamesAllocated);
LWLockTrancheNamesAllocated = newalloc;
}
diff --git a/src/backend/utils/adt/ruleutils.c
b/src/backend/utils/adt/ruleutils.c
index 2b7b1b0c0f..0cd63383ec 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -4855,14 +4855,9 @@ expand_colnames_array_to(deparse_columns *colinfo, int n)
if (n > colinfo->num_cols)
{
if (colinfo->colnames == NULL)
- colinfo->colnames = (char **) palloc0(n * sizeof(char
*));
+ colinfo->colnames = palloc0_array(char *, n);
else
- {
- colinfo->colnames = (char **)
repalloc(colinfo->colnames,
-
n * sizeof(char *));
- memset(colinfo->colnames + colinfo->num_cols, 0,
- (n - colinfo->num_cols) * sizeof(char *));
- }
+ colinfo->colnames = repalloc0_array(colinfo->colnames,
char *, n, colinfo->num_cols);
colinfo->num_cols = n;
}
}
diff --git a/src/backend/utils/cache/typcache.c
b/src/backend/utils/cache/typcache.c
index 808f9ebd0d..739765cb09 100644
--- a/src/backend/utils/cache/typcache.c
+++ b/src/backend/utils/cache/typcache.c
@@ -1714,14 +1714,8 @@ ensure_record_cache_typmod_slot_exists(int32 typmod)
{
int32 newlen = pg_nextpower2_32(typmod + 1);
- RecordCacheArray = (TupleDesc *) repalloc(RecordCacheArray,
-
newlen * sizeof(TupleDesc));
- memset(RecordCacheArray + RecordCacheArrayLen, 0,
- (newlen - RecordCacheArrayLen) * sizeof(TupleDesc));
- RecordIdentifierArray = (uint64 *)
repalloc(RecordIdentifierArray,
-
newlen * sizeof(uint64));
- memset(RecordIdentifierArray + RecordCacheArrayLen, 0,
- (newlen - RecordCacheArrayLen) * sizeof(uint64));
+ RecordCacheArray = repalloc0_array(RecordCacheArray, TupleDesc,
newlen, RecordCacheArrayLen);
+ RecordIdentifierArray = repalloc0_array(RecordIdentifierArray,
uint64, newlen, RecordCacheArrayLen);
RecordCacheArrayLen = newlen;
}
}
diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c
index 115a64cfe4..027af1e5de 100644
--- a/src/backend/utils/mmgr/mcxt.c
+++ b/src/backend/utils/mmgr/mcxt.c
@@ -1297,6 +1297,21 @@ repalloc(void *pointer, Size size)
return ret;
}
+/*
+ * repalloc
+ * Adjust the size of a previously allocated chunk and zero out
the added
+ * space.
+ */
+void *
+repalloc0(void *pointer, Size size, Size oldsize)
+{
+ void *ret;
+
+ ret = repalloc(pointer, size);
+ memset((char *) ret + oldsize, 0, (size - oldsize));
+ return ret;
+}
+
/*
* MemoryContextAllocHuge
* Allocate (possibly-expansive) space within the specified
context.
diff --git a/src/include/utils/palloc.h b/src/include/utils/palloc.h
index a0b62aa7b0..af7a4a2311 100644
--- a/src/include/utils/palloc.h
+++ b/src/include/utils/palloc.h
@@ -78,6 +78,7 @@ extern void *palloc(Size size);
extern void *palloc0(Size size);
extern void *palloc_extended(Size size, int flags);
extern pg_nodiscard void *repalloc(void *pointer, Size size);
+extern pg_nodiscard void *repalloc0(void *pointer, Size size, Size oldsize);
extern void pfree(void *pointer);
/*
@@ -101,6 +102,7 @@ extern void pfree(void *pointer);
* objects of type "type"
*/
#define repalloc_array(pointer, type, count) ((type *) repalloc(pointer,
sizeof(type) * (count)))
+#define repalloc0_array(pointer, type, count, oldcount) ((type *)
repalloc0(pointer, sizeof(type) * (count), sizeof(type) * (oldcount)))
/*
* The result of palloc() is always word-aligned, so we can skip testing
--
2.37.3
