open-dsi
/
postgres
mirror of https://github.com/postgres/postgres
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Rearrange dblink's dblink_build_sql_insert() and related routines to open and

Browse Source 
lock the target relation just once per SQL function call.  The original coding
obtained and released lock several times per call.  Aside from saving a
not-insignificant number of cycles, this eliminates possible race conditions
if someone tries to modify the relation's schema concurrently.  Also
centralize locking and permission-checking logic.

Problem noted while investigating a trouble report from Robert Voinea --- his
problem is still to be fixed, though.
REL9_0_STABLE
Tom Lane 15 years ago
parent cbb0dcff4f
commit 6bbaa3148d
1 changed files with 83 additions and 126 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 209
      contrib/dblink/dblink.c

209
contrib/dblink/dblink.c
Unescape View File

@ -8,7 +8,7 @@
* Darko Prenosil <Darko.Prenosil@finteh.hr>
* Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
*
* $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.94 2010/06/09 03:39:26 itagaki Exp $
* $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.95 2010/06/14 20:49:33 tgl Exp $
* Copyright (c) 2001-2010, PostgreSQL Global Development Group
* ALL RIGHTS RESERVED;
*
@ -86,23 +86,23 @@ static remoteConn *getConnectionByName(const char *name);
static HTAB *createConnHash(void);
static void createNewConnection(const char *name, remoteConn *rconn);
static void deleteConnection(const char *name);
static char **get_pkey_attnames(Oid relid, int16 *numatts);
static char **get_pkey_attnames(Relation rel, int16 *numatts);
static char **get_text_array_contents(ArrayType *array, int *numitems);
static char *get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pkattvals);
static char *get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *get_sql_insert(Relation rel, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *get_sql_delete(Relation rel, int2vector *pkattnums, int16 pknumatts, char **tgt_pkattvals);
static char *get_sql_update(Relation rel, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals);
static char *quote_literal_cstr(char *rawstr);
static char *quote_ident_cstr(char *rawstr);
static int16 get_attnum_pk_pos(int2vector *pkattnums, int16 pknumatts, int16 key);
static HeapTuple get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals);
static Oid get_relid_from_relname(text *relname_text);
static char *generate_relation_name(Oid relid);
static HeapTuple get_tuple_of_interest(Relation rel, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals);
static Relation get_rel_from_relname(text *relname_text, LOCKMODE lockmode, AclMode aclmode);
static char *generate_relation_name(Relation rel);
static void dblink_connstr_check(const char *connstr);
static void dblink_security_check(PGconn *conn, remoteConn *rconn);
static void dblink_res_error(const char *conname, PGresult *res, const char *dblink_context_msg, bool fail);
static char *get_connect_string(const char *servername);
static char *escape_param_str(const char *from);
static int get_nondropped_natts(Oid relid);
static int get_nondropped_natts(Relation rel);
/* Global */
static remoteConn *pconn = NULL;
@ -1112,7 +1112,6 @@ Datum
dblink_get_pkey(PG_FUNCTION_ARGS)
{
int16 numatts;
Oid relid;
char **results;
FuncCallContext *funcctx;
int32 call_cntr;
@ -1123,7 +1122,8 @@ dblink_get_pkey(PG_FUNCTION_ARGS)
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc = NULL;
Relation rel;
TupleDesc tupdesc;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
@ -1133,13 +1133,13 @@ dblink_get_pkey(PG_FUNCTION_ARGS)
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* convert relname to rel Oid */
relid = get_relid_from_relname(PG_GETARG_TEXT_P(0));
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
text_to_cstring(PG_GETARG_TEXT_PP(0)))));
/* open target relation */
rel = get_rel_from_relname(PG_GETARG_TEXT_P(0), AccessShareLock, ACL_SELECT);
/* get the array of attnums */
results = get_pkey_attnames(rel, &numatts);
relation_close(rel, AccessShareLock);
/*
* need a tuple descriptor representing one INT and one TEXT column
@ -1157,9 +1157,6 @@ dblink_get_pkey(PG_FUNCTION_ARGS)
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
/* get an array of attnums */
results = get_pkey_attnames(relid, &numatts);
if ((results != NULL) && (numatts > 0))
{
funcctx->max_calls = numatts;
@ -1246,7 +1243,7 @@ dblink_build_sql_insert(PG_FUNCTION_ARGS)
int32 pknumatts_tmp = PG_GETARG_INT32(2);
ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
Oid relid;
Relation rel;
int16 pknumatts = 0;
char **src_pkattvals;
char **tgt_pkattvals;
@ -1256,14 +1253,9 @@ dblink_build_sql_insert(PG_FUNCTION_ARGS)
int nondropped_natts;
/*
* Convert relname to rel OID.
* Open target relation.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
text_to_cstring(relname_text))));
rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
/*
* There should be at least one key attribute
@ -1285,7 +1277,7 @@ dblink_build_sql_insert(PG_FUNCTION_ARGS)
* ensure we don't ask for more pk attributes than we have non-dropped
* columns
*/
nondropped_natts = get_nondropped_natts(relid);
nondropped_natts = get_nondropped_natts(rel);
if (pknumatts > nondropped_natts)
ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR),
errmsg("number of primary key fields exceeds number of specified relation attributes")));
@ -1323,7 +1315,12 @@ dblink_build_sql_insert(PG_FUNCTION_ARGS)
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_insert(relid, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
sql = get_sql_insert(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
/*
* Now we can close the relation.
*/
relation_close(rel, AccessShareLock);
/*
* And send it
@ -1356,21 +1353,16 @@ dblink_build_sql_delete(PG_FUNCTION_ARGS)
int32 pknumatts_tmp = PG_GETARG_INT32(2);
ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
int nondropped_natts;
Oid relid;
Relation rel;
int16 pknumatts = 0;
char **tgt_pkattvals;
int tgt_nitems;
char *sql;
/*
* Convert relname to rel OID.
* Open target relation.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
text_to_cstring(relname_text))));
rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
/*
* There should be at least one key attribute
@ -1392,7 +1384,7 @@ dblink_build_sql_delete(PG_FUNCTION_ARGS)
* ensure we don't ask for more pk attributes than we have non-dropped
* columns
*/
nondropped_natts = get_nondropped_natts(relid);
nondropped_natts = get_nondropped_natts(rel);
if (pknumatts > nondropped_natts)
ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR),
errmsg("number of primary key fields exceeds number of specified relation attributes")));
@ -1415,7 +1407,12 @@ dblink_build_sql_delete(PG_FUNCTION_ARGS)
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_delete(relid, pkattnums, pknumatts, tgt_pkattvals);
sql = get_sql_delete(rel, pkattnums, pknumatts, tgt_pkattvals);
/*
* Now we can close the relation.
*/
relation_close(rel, AccessShareLock);
/*
* And send it
@ -1453,7 +1450,7 @@ dblink_build_sql_update(PG_FUNCTION_ARGS)
ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
int nondropped_natts;
Oid relid;
Relation rel;
int16 pknumatts = 0;
char **src_pkattvals;
char **tgt_pkattvals;
@ -1462,14 +1459,9 @@ dblink_build_sql_update(PG_FUNCTION_ARGS)
char *sql;
/*
* Convert relname to rel OID.
* Open target relation.
*/
relid = get_relid_from_relname(relname_text);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
text_to_cstring(relname_text))));
rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
/*
* There should be one source array key values for each key attnum
@ -1491,7 +1483,7 @@ dblink_build_sql_update(PG_FUNCTION_ARGS)
* ensure we don't ask for more pk attributes than we have non-dropped
* columns
*/
nondropped_natts = get_nondropped_natts(relid);
nondropped_natts = get_nondropped_natts(rel);
if (pknumatts > nondropped_natts)
ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR),
errmsg("number of primary key fields exceeds number of specified relation attributes")));
@ -1529,7 +1521,12 @@ dblink_build_sql_update(PG_FUNCTION_ARGS)
/*
* Prep work is finally done. Go get the SQL string.
*/
sql = get_sql_update(relid, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
sql = get_sql_update(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
/*
* Now we can close the relation.
*/
relation_close(rel, AccessShareLock);
/*
* And send it
@ -1643,7 +1640,7 @@ dblink_get_notify(PG_FUNCTION_ARGS)
* Return NULL, and set numatts = 0, if no primary key exists.
*/
static char **
get_pkey_attnames(Oid relid, int16 *numatts)
get_pkey_attnames(Relation rel, int16 *numatts)
{
Relation indexRelation;
ScanKeyData skey;
@ -1651,22 +1648,11 @@ get_pkey_attnames(Oid relid, int16 *numatts)
HeapTuple indexTuple;
int i;
char **result = NULL;
Relation rel;
TupleDesc tupdesc;
AclResult aclresult;
/* initialize numatts to 0 in case no primary key exists */
*numatts = 0;
/* open relation using relid, check permissions, get tupdesc */
rel = relation_open(relid, AccessShareLock);
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(rel));
tupdesc = rel->rd_att;
/* Prepare to scan pg_index for entries having indrelid = this rel. */
@ -1674,7 +1660,7 @@ get_pkey_attnames(Oid relid, int16 *numatts)
ScanKeyInit(&skey,
Anum_pg_index_indrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
ObjectIdGetDatum(RelationGetRelid(rel)));
scan = systable_beginscan(indexRelation, IndexIndrelidIndexId, true,
SnapshotNow, 1, &skey);
@ -1700,7 +1686,6 @@ get_pkey_attnames(Oid relid, int16 *numatts)
systable_endscan(scan);
heap_close(indexRelation, AccessShareLock);
relation_close(rel, AccessShareLock);
return result;
}
@ -1766,9 +1751,8 @@ get_text_array_contents(ArrayType *array, int *numitems)
}
static char *
get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals)
get_sql_insert(Relation rel, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals)
{
Relation rel;
char *relname;
HeapTuple tuple;
TupleDesc tupdesc;
@ -1782,16 +1766,12 @@ get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
relname = generate_relation_name(rel);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
tuple = get_tuple_of_interest(relid, pkattnums, pknumatts, src_pkattvals);
tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
if (!tuple)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
@ -1848,14 +1828,12 @@ get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
}
appendStringInfo(&buf, ")");
relation_close(rel, AccessShareLock);
return (buf.data);
}
static char *
get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pkattvals)
get_sql_delete(Relation rel, int2vector *pkattnums, int16 pknumatts, char **tgt_pkattvals)
{
Relation rel;
char *relname;
TupleDesc tupdesc;
int natts;
@ -1865,12 +1843,8 @@ get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pka
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
relname = generate_relation_name(rel);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
@ -1896,14 +1870,12 @@ get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pka
appendStringInfo(&buf, " IS NULL");
}
relation_close(rel, AccessShareLock);
return (buf.data);
}
static char *
get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals)
get_sql_update(Relation rel, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals, char **tgt_pkattvals)
{
Relation rel;
char *relname;
HeapTuple tuple;
TupleDesc tupdesc;
@ -1917,16 +1889,12 @@ get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
relname = generate_relation_name(rel);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
tuple = get_tuple_of_interest(relid, pkattnums, pknumatts, src_pkattvals);
tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
if (!tuple)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
@ -1992,7 +1960,6 @@ get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
appendStringInfo(&buf, " IS NULL");
}
relation_close(rel, AccessShareLock);
return (buf.data);
}
@ -2050,9 +2017,8 @@ get_attnum_pk_pos(int2vector *pkattnums, int16 pknumatts, int16 key)
}
static HeapTuple
get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals)
get_tuple_of_interest(Relation rel, int2vector *pkattnums, int16 pknumatts, char **src_pkattvals)
{
Relation rel;
char *relname;
TupleDesc tupdesc;
StringInfoData buf;
@ -2063,14 +2029,9 @@ get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **
initStringInfo(&buf);
/* get relation name including any needed schema prefix and quoting */
relname = generate_relation_name(relid);
relname = generate_relation_name(rel);
/*
* Open relation using relid
*/
rel = relation_open(relid, AccessShareLock);
tupdesc = CreateTupleDescCopy(rel->rd_att);
relation_close(rel, AccessShareLock);
tupdesc = rel->rd_att;
/*
* Connect to SPI manager
@ -2141,50 +2102,49 @@ get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **
return NULL;
}
static Oid
get_relid_from_relname(text *relname_text)
/*
* Open the relation named by relname_text, acquire specified type of lock,
* verify we have specified permissions.
* Caller must close rel when done with it.
*/
static Relation
get_rel_from_relname(text *relname_text, LOCKMODE lockmode, AclMode aclmode)
{
RangeVar *relvar;
Relation rel;
Oid relid;
AclResult aclresult;
relvar = makeRangeVarFromNameList(textToQualifiedNameList(relname_text));
rel = heap_openrv(relvar, AccessShareLock);
relid = RelationGetRelid(rel);
relation_close(rel, AccessShareLock);
rel = heap_openrv(relvar, lockmode);
return relid;
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
aclmode);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(rel));
return rel;
}
/*
* generate_relation_name - copied from ruleutils.c
* Compute the name to display for a relation specified by OID
* Compute the name to display for a relation
*
* The result includes all necessary quoting and schema-prefixing.
*/
static char *
generate_relation_name(Oid relid)
generate_relation_name(Relation rel)
{
HeapTuple tp;
Form_pg_class reltup;
char *nspname;
char *result;
tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for relation %u", relid);
reltup = (Form_pg_class) GETSTRUCT(tp);
/* Qualify the name if not visible in search path */
if (RelationIsVisible(relid))
if (RelationIsVisible(RelationGetRelid(rel)))
nspname = NULL;
else
nspname = get_namespace_name(reltup->relnamespace);
nspname = get_namespace_name(rel->rd_rel->relnamespace);
result = quote_qualified_identifier(nspname, NameStr(reltup->relname));
ReleaseSysCache(tp);
result = quote_qualified_identifier(nspname, RelationGetRelationName(rel));
return result;
}
@ -2469,15 +2429,13 @@ escape_param_str(const char *str)
}
static int
get_nondropped_natts(Oid relid)
get_nondropped_natts(Relation rel)
{
int nondropped_natts = 0;
TupleDesc tupdesc;
Relation rel;
int natts;
int i;
rel = relation_open(relid, AccessShareLock);
tupdesc = rel->rd_att;
natts = tupdesc->natts;
@ -2488,6 +2446,5 @@ get_nondropped_natts(Oid relid)
nondropped_natts++;
}
relation_close(rel, AccessShareLock);
return nondropped_natts;
}

Write Preview
Loading…
Cancel
Save