mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-09-30 18:41:16 +02:00
0144eb92bb
opclass. This is not so much because anyone's likely to create an index on TID, as that sorting TIDs can be useful. Also added max and min aggregates while at it, so that one can investigate the clusteredness of a table with queries like SELECT min(ctid), max(ctid) FROM tab WHERE ... Greg Stark and Tom Lane
395 lines
9.3 KiB
C
395 lines
9.3 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* tid.c
|
|
* Functions for the built-in type tuple id
|
|
*
|
|
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
*
|
|
* IDENTIFICATION
|
|
* $PostgreSQL: pgsql/src/backend/utils/adt/tid.c,v 1.54 2006/07/21 20:51:32 tgl Exp $
|
|
*
|
|
* NOTES
|
|
* input routine largely stolen from boxin().
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#include "postgres.h"
|
|
|
|
#include <math.h>
|
|
#include <limits.h>
|
|
|
|
#include "access/heapam.h"
|
|
#include "catalog/namespace.h"
|
|
#include "catalog/pg_type.h"
|
|
#include "libpq/pqformat.h"
|
|
#include "parser/parsetree.h"
|
|
#include "utils/builtins.h"
|
|
|
|
|
|
#define DatumGetItemPointer(X) ((ItemPointer) DatumGetPointer(X))
|
|
#define ItemPointerGetDatum(X) PointerGetDatum(X)
|
|
#define PG_GETARG_ITEMPOINTER(n) DatumGetItemPointer(PG_GETARG_DATUM(n))
|
|
#define PG_RETURN_ITEMPOINTER(x) return ItemPointerGetDatum(x)
|
|
|
|
#define LDELIM '('
|
|
#define RDELIM ')'
|
|
#define DELIM ','
|
|
#define NTIDARGS 2
|
|
|
|
/* ----------------------------------------------------------------
|
|
* tidin
|
|
* ----------------------------------------------------------------
|
|
*/
|
|
Datum
|
|
tidin(PG_FUNCTION_ARGS)
|
|
{
|
|
char *str = PG_GETARG_CSTRING(0);
|
|
char *p,
|
|
*coord[NTIDARGS];
|
|
int i;
|
|
ItemPointer result;
|
|
BlockNumber blockNumber;
|
|
OffsetNumber offsetNumber;
|
|
char *badp;
|
|
int hold_offset;
|
|
|
|
for (i = 0, p = str; *p && i < NTIDARGS && *p != RDELIM; p++)
|
|
if (*p == DELIM || (*p == LDELIM && !i))
|
|
coord[i++] = p + 1;
|
|
|
|
if (i < NTIDARGS)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
|
|
errmsg("invalid input syntax for type tid: \"%s\"",
|
|
str)));
|
|
|
|
errno = 0;
|
|
blockNumber = strtoul(coord[0], &badp, 10);
|
|
if (errno || *badp != DELIM)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
|
|
errmsg("invalid input syntax for type tid: \"%s\"",
|
|
str)));
|
|
|
|
hold_offset = strtol(coord[1], &badp, 10);
|
|
if (errno || *badp != RDELIM ||
|
|
hold_offset > USHRT_MAX || hold_offset < 0)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
|
|
errmsg("invalid input syntax for type tid: \"%s\"",
|
|
str)));
|
|
|
|
offsetNumber = hold_offset;
|
|
|
|
result = (ItemPointer) palloc(sizeof(ItemPointerData));
|
|
|
|
ItemPointerSet(result, blockNumber, offsetNumber);
|
|
|
|
PG_RETURN_ITEMPOINTER(result);
|
|
}
|
|
|
|
/* ----------------------------------------------------------------
|
|
* tidout
|
|
* ----------------------------------------------------------------
|
|
*/
|
|
Datum
|
|
tidout(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer itemPtr = PG_GETARG_ITEMPOINTER(0);
|
|
BlockNumber blockNumber;
|
|
OffsetNumber offsetNumber;
|
|
char buf[32];
|
|
|
|
blockNumber = BlockIdGetBlockNumber(&(itemPtr->ip_blkid));
|
|
offsetNumber = itemPtr->ip_posid;
|
|
|
|
/* Perhaps someday we should output this as a record. */
|
|
snprintf(buf, sizeof(buf), "(%u,%u)", blockNumber, offsetNumber);
|
|
|
|
PG_RETURN_CSTRING(pstrdup(buf));
|
|
}
|
|
|
|
/*
|
|
* tidrecv - converts external binary format to tid
|
|
*/
|
|
Datum
|
|
tidrecv(PG_FUNCTION_ARGS)
|
|
{
|
|
StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
|
|
ItemPointer result;
|
|
BlockNumber blockNumber;
|
|
OffsetNumber offsetNumber;
|
|
|
|
blockNumber = pq_getmsgint(buf, sizeof(blockNumber));
|
|
offsetNumber = pq_getmsgint(buf, sizeof(offsetNumber));
|
|
|
|
result = (ItemPointer) palloc(sizeof(ItemPointerData));
|
|
|
|
ItemPointerSet(result, blockNumber, offsetNumber);
|
|
|
|
PG_RETURN_ITEMPOINTER(result);
|
|
}
|
|
|
|
/*
|
|
* tidsend - converts tid to binary format
|
|
*/
|
|
Datum
|
|
tidsend(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer itemPtr = PG_GETARG_ITEMPOINTER(0);
|
|
BlockId blockId;
|
|
BlockNumber blockNumber;
|
|
OffsetNumber offsetNumber;
|
|
StringInfoData buf;
|
|
|
|
blockId = &(itemPtr->ip_blkid);
|
|
blockNumber = BlockIdGetBlockNumber(blockId);
|
|
offsetNumber = itemPtr->ip_posid;
|
|
|
|
pq_begintypsend(&buf);
|
|
pq_sendint(&buf, blockNumber, sizeof(blockNumber));
|
|
pq_sendint(&buf, offsetNumber, sizeof(offsetNumber));
|
|
PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
|
|
}
|
|
|
|
/*****************************************************************************
|
|
* PUBLIC ROUTINES *
|
|
*****************************************************************************/
|
|
|
|
static int32
|
|
tid_cmp_internal(ItemPointer arg1, ItemPointer arg2)
|
|
{
|
|
/*
|
|
* Don't use ItemPointerGetBlockNumber or ItemPointerGetOffsetNumber here,
|
|
* because they assert ip_posid != 0 which might not be true for a
|
|
* user-supplied TID.
|
|
*/
|
|
BlockNumber b1 = BlockIdGetBlockNumber(&(arg1->ip_blkid));
|
|
BlockNumber b2 = BlockIdGetBlockNumber(&(arg2->ip_blkid));
|
|
|
|
if (b1 < b2)
|
|
return -1;
|
|
else if (b1 > b2)
|
|
return 1;
|
|
else if (arg1->ip_posid < arg2->ip_posid)
|
|
return -1;
|
|
else if (arg1->ip_posid > arg2->ip_posid)
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
Datum
|
|
tideq(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) == 0);
|
|
}
|
|
|
|
Datum
|
|
tidne(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) != 0);
|
|
}
|
|
|
|
Datum
|
|
tidlt(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) < 0);
|
|
}
|
|
|
|
Datum
|
|
tidle(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) <= 0);
|
|
}
|
|
|
|
Datum
|
|
tidgt(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) > 0);
|
|
}
|
|
|
|
Datum
|
|
tidge(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) >= 0);
|
|
}
|
|
|
|
Datum
|
|
bttidcmp(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_INT32(tid_cmp_internal(arg1, arg2));
|
|
}
|
|
|
|
Datum
|
|
tidlarger(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_ITEMPOINTER(tid_cmp_internal(arg1,arg2) >= 0 ? arg1 : arg2);
|
|
}
|
|
|
|
Datum
|
|
tidsmaller(PG_FUNCTION_ARGS)
|
|
{
|
|
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
|
|
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
|
|
|
|
PG_RETURN_ITEMPOINTER(tid_cmp_internal(arg1,arg2) <= 0 ? arg1 : arg2);
|
|
}
|
|
|
|
|
|
/*
|
|
* Functions to get latest tid of a specified tuple.
|
|
*
|
|
* Maybe these implementations should be moved to another place
|
|
*/
|
|
|
|
static ItemPointerData Current_last_tid = {{0, 0}, 0};
|
|
|
|
void
|
|
setLastTid(const ItemPointer tid)
|
|
{
|
|
Current_last_tid = *tid;
|
|
}
|
|
|
|
/*
|
|
* Handle CTIDs of views.
|
|
* CTID should be defined in the view and it must
|
|
* correspond to the CTID of a base relation.
|
|
*/
|
|
static Datum
|
|
currtid_for_view(Relation viewrel, ItemPointer tid)
|
|
{
|
|
TupleDesc att = RelationGetDescr(viewrel);
|
|
RuleLock *rulelock;
|
|
RewriteRule *rewrite;
|
|
int i,
|
|
natts = att->natts,
|
|
tididx = -1;
|
|
|
|
for (i = 0; i < natts; i++)
|
|
{
|
|
if (strcmp(NameStr(att->attrs[i]->attname), "ctid") == 0)
|
|
{
|
|
if (att->attrs[i]->atttypid != TIDOID)
|
|
elog(ERROR, "ctid isn't of type TID");
|
|
tididx = i;
|
|
break;
|
|
}
|
|
}
|
|
if (tididx < 0)
|
|
elog(ERROR, "currtid cannot handle views with no CTID");
|
|
rulelock = viewrel->rd_rules;
|
|
if (!rulelock)
|
|
elog(ERROR, "the view has no rules");
|
|
for (i = 0; i < rulelock->numLocks; i++)
|
|
{
|
|
rewrite = rulelock->rules[i];
|
|
if (rewrite->event == CMD_SELECT)
|
|
{
|
|
Query *query;
|
|
TargetEntry *tle;
|
|
|
|
if (list_length(rewrite->actions) != 1)
|
|
elog(ERROR, "only one select rule is allowed in views");
|
|
query = (Query *) linitial(rewrite->actions);
|
|
tle = get_tle_by_resno(query->targetList, tididx + 1);
|
|
if (tle && tle->expr && IsA(tle->expr, Var))
|
|
{
|
|
Var *var = (Var *) tle->expr;
|
|
RangeTblEntry *rte;
|
|
|
|
if (var->varno > 0 && var->varno < INNER &&
|
|
var->varattno == SelfItemPointerAttributeNumber)
|
|
{
|
|
rte = rt_fetch(var->varno, query->rtable);
|
|
if (rte)
|
|
{
|
|
heap_close(viewrel, AccessShareLock);
|
|
return DirectFunctionCall2(currtid_byreloid, ObjectIdGetDatum(rte->relid), PointerGetDatum(tid));
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
elog(ERROR, "currtid cannot handle this view");
|
|
return (Datum) 0;
|
|
}
|
|
|
|
Datum
|
|
currtid_byreloid(PG_FUNCTION_ARGS)
|
|
{
|
|
Oid reloid = PG_GETARG_OID(0);
|
|
ItemPointer tid = PG_GETARG_ITEMPOINTER(1);
|
|
ItemPointer result;
|
|
Relation rel;
|
|
|
|
result = (ItemPointer) palloc(sizeof(ItemPointerData));
|
|
if (!reloid)
|
|
{
|
|
*result = Current_last_tid;
|
|
PG_RETURN_ITEMPOINTER(result);
|
|
}
|
|
|
|
rel = heap_open(reloid, AccessShareLock);
|
|
if (rel->rd_rel->relkind == RELKIND_VIEW)
|
|
return currtid_for_view(rel, tid);
|
|
|
|
ItemPointerCopy(tid, result);
|
|
heap_get_latest_tid(rel, SnapshotNow, result);
|
|
|
|
heap_close(rel, AccessShareLock);
|
|
|
|
PG_RETURN_ITEMPOINTER(result);
|
|
}
|
|
|
|
Datum
|
|
currtid_byrelname(PG_FUNCTION_ARGS)
|
|
{
|
|
text *relname = PG_GETARG_TEXT_P(0);
|
|
ItemPointer tid = PG_GETARG_ITEMPOINTER(1);
|
|
ItemPointer result;
|
|
RangeVar *relrv;
|
|
Relation rel;
|
|
|
|
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
|
|
rel = heap_openrv(relrv, AccessShareLock);
|
|
if (rel->rd_rel->relkind == RELKIND_VIEW)
|
|
return currtid_for_view(rel, tid);
|
|
|
|
result = (ItemPointer) palloc(sizeof(ItemPointerData));
|
|
ItemPointerCopy(tid, result);
|
|
|
|
heap_get_latest_tid(rel, SnapshotNow, result);
|
|
|
|
heap_close(rel, AccessShareLock);
|
|
|
|
PG_RETURN_ITEMPOINTER(result);
|
|
}
|