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Clean up a couple of problems in crosstab_hash's use of a hash table. 

The original coding leaked memory (at least 8K per crosstab_hash call)
because it allowed the hash table to be allocated as a child of
TopMemoryContext and then never freed it.  Fix that by putting the
hash table under per_query_ctx, instead.  Also get rid of use
of a static variable to point to the hash table.  Aside from being
ugly, that would actively do the wrong thing in the case of re-entrant
calls to crosstab_hash, which are at least theoretically possible
since it was expecting the static variable to stay valid across
a SPI_execute call.
This commit is contained in:
Tom Lane 2007-12-07 16:44:58 +00:00
parent cac82bb20c
commit aaff0a559f
1 changed files with 25 additions and 22 deletions
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47
contrib/tablefunc/tablefunc.c
View File

@ -44,9 +44,9 @@
PG_MODULE_MAGIC;
static int load_categories_hash(char *cats_sql, MemoryContext per_query_ctx);
static HTAB *load_categories_hash(char *cats_sql, MemoryContext per_query_ctx);
static Tuplestorestate *get_crosstab_tuplestore(char *sql,
int num_categories,
HTAB *crosstab_hash,
TupleDesc tupdesc,
MemoryContext per_query_ctx);
static void validateConnectbyTupleDesc(TupleDesc tupdesc, bool show_branch, bool show_serial);
@ -121,26 +121,23 @@ typedef struct
/* sign, 10 digits, '\0' */
#define INT32_STRLEN 12
/* hash table support */
static HTAB *crosstab_HashTable;
/* The information we cache about loaded procedures */
/* stored info for a crosstab category */
typedef struct crosstab_cat_desc
{
char *catname;
char *catname; /* full category name */
int attidx; /* zero based */
} crosstab_cat_desc;
#define MAX_CATNAME_LEN NAMEDATALEN
#define INIT_CATS 64
#define crosstab_HashTableLookup(CATNAME, CATDESC) \
#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(crosstab_HashTable, \
hentry = (crosstab_HashEnt*) hash_search(HASHTAB, \
key, HASH_FIND, NULL); \
if (hentry) \
CATDESC = hentry->catdesc; \
@ -148,13 +145,13 @@ do { \
CATDESC = NULL; \
} while(0)
#define crosstab_HashTableInsert(CATDESC) \
#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(crosstab_HashTable, \
hentry = (crosstab_HashEnt*) hash_search(HASHTAB, \
key, HASH_ENTER, &found); \
if (found) \
ereport(ERROR, \
@ -704,7 +701,7 @@ crosstab_hash(PG_FUNCTION_ARGS)
TupleDesc tupdesc;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
int num_categories;
HTAB *crosstab_hash;
/* check to see if caller supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
@ -737,14 +734,14 @@ crosstab_hash(PG_FUNCTION_ARGS)
"crosstab function are not compatible")));
/* load up the categories hash table */
num_categories = load_categories_hash(cats_sql, per_query_ctx);
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,
num_categories,
crosstab_hash,
tupdesc,
per_query_ctx);
@ -764,24 +761,29 @@ crosstab_hash(PG_FUNCTION_ARGS)
/*
* load up the categories hash table
*/
static int
static HTAB *
load_categories_hash(char *cats_sql, MemoryContext per_query_ctx)
{
HTAB *crosstab_hash;
HASHCTL ctl;
int ret;
int proc;
MemoryContext SPIcontext;
int num_categories = 0;
/* initialize the category hash table */
MemSet(&ctl, 0, sizeof(ctl));
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_HashTable = hash_create("crosstab hash", INIT_CATS, &ctl, HASH_ELEM);
crosstab_hash = hash_create("crosstab hash",
INIT_CATS,
&ctl,
HASH_ELEM | HASH_CONTEXT);
/* Connect to SPI manager */
if ((ret = SPI_connect()) < 0)
@ -790,7 +792,7 @@ load_categories_hash(char *cats_sql, MemoryContext per_query_ctx)
/* Retrieve the category name rows */
ret = SPI_execute(cats_sql, true, 0);
num_categories = proc = SPI_processed;
proc = SPI_processed;
/* Check for qualifying tuples */
if ((ret == SPI_OK_SELECT) && (proc > 0))
@ -828,7 +830,7 @@ load_categories_hash(char *cats_sql, MemoryContext per_query_ctx)
catdesc->attidx = i;
/* Add the proc description block to the hashtable */
crosstab_HashTableInsert(catdesc);
crosstab_HashTableInsert(crosstab_hash, catdesc);
MemoryContextSwitchTo(SPIcontext);
}
@ -838,7 +840,7 @@ load_categories_hash(char *cats_sql, MemoryContext per_query_ctx)
/* internal error */
elog(ERROR, "load_categories_hash: SPI_finish() failed");
return num_categories;
return crosstab_hash;
}
/*
@ -846,11 +848,12 @@ load_categories_hash(char *cats_sql, MemoryContext per_query_ctx)
*/
static Tuplestorestate *
get_crosstab_tuplestore(char *sql,
int num_categories,
HTAB *crosstab_hash,
TupleDesc tupdesc,
MemoryContext per_query_ctx)
{
Tuplestorestate *tupstore;
int num_categories = hash_get_num_entries(crosstab_hash);
AttInMetadata *attinmeta = TupleDescGetAttInMetadata(tupdesc);
char **values;
HeapTuple tuple;
@ -978,7 +981,7 @@ get_crosstab_tuplestore(char *sql,
if (catname != NULL)
{
crosstab_HashTableLookup(catname, catdesc);
crosstab_HashTableLookup(crosstab_hash, catname, catdesc);
if (catdesc)
values[catdesc->attidx + ncols - 2] =