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Restructure index access method API to hide most of it at the C level.

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This patch reduces pg_am to just two columns, a name and a handler
function.  All the data formerly obtained from pg_am is now provided
in a C struct returned by the handler function.  This is similar to
the designs we've adopted for FDWs and tablesample methods.  There
are multiple advantages.  For one, the index AM's support functions
are now simple C functions, making them faster to call and much less
error-prone, since the C compiler can now check function signatures.
For another, this will make it far more practical to define index access
methods in installable extensions.

A disadvantage is that SQL-level code can no longer see attributes
of index AMs; in particular, some of the crosschecks in the opr_sanity
regression test are no longer possible from SQL.  We've addressed that
by adding a facility for the index AM to perform such checks instead.
(Much more could be done in that line, but for now we're content if the
amvalidate functions more or less replace what opr_sanity used to do.)
We might also want to expose some sort of reporting functionality, but
this patch doesn't do that.

Alexander Korotkov, reviewed by Petr Jelínek, and rather heavily
editorialized on by me.
This commit is contained in:
Tom Lane
2016-01-17 19:36:59 -05:00
parent 8d290c8ec6
commit 65c5fcd353
93 changed files with 2493 additions and 1924 deletions
Download Patch File Download Diff File Expand all files Collapse all files

165
src/backend/access/nbtree/nbtree.c
View File

@@ -28,7 +28,7 @@
#include "storage/ipc.h"
#include "storage/lmgr.h"
#include "storage/smgr.h"
#include "tcop/tcopprot.h"
#include "utils/index_selfuncs.h"
#include "utils/memutils.h"
@@ -77,14 +77,55 @@ static void btvacuumpage(BTVacState *vstate, BlockNumber blkno,
/*
* btbuild() -- build a new btree index.
* Btree handler function: return IndexAmRoutine with access method parameters
* and callbacks.
*/
Datum
btbuild(PG_FUNCTION_ARGS)
bthandler(PG_FUNCTION_ARGS)
{
IndexAmRoutine *amroutine = makeNode(IndexAmRoutine);
amroutine->amstrategies = 5;
amroutine->amsupport = 2;
amroutine->amcanorder = true;
amroutine->amcanorderbyop = false;
amroutine->amcanbackward = true;
amroutine->amcanunique = true;
amroutine->amcanmulticol = true;
amroutine->amoptionalkey = true;
amroutine->amsearcharray = true;
amroutine->amsearchnulls = true;
amroutine->amstorage = false;
amroutine->amclusterable = true;
amroutine->ampredlocks = true;
amroutine->amkeytype = InvalidOid;
amroutine->ambuild = btbuild;
amroutine->ambuildempty = btbuildempty;
amroutine->aminsert = btinsert;
amroutine->ambulkdelete = btbulkdelete;
amroutine->amvacuumcleanup = btvacuumcleanup;
amroutine->amcanreturn = btcanreturn;
amroutine->amcostestimate = btcostestimate;
amroutine->amoptions = btoptions;
amroutine->amvalidate = btvalidate;
amroutine->ambeginscan = btbeginscan;
amroutine->amrescan = btrescan;
amroutine->amgettuple = btgettuple;
amroutine->amgetbitmap = btgetbitmap;
amroutine->amendscan = btendscan;
amroutine->ammarkpos = btmarkpos;
amroutine->amrestrpos = btrestrpos;
PG_RETURN_POINTER(amroutine);
}
/*
* btbuild() -- build a new btree index.
*/
IndexBuildResult *
btbuild(Relation heap, Relation index, IndexInfo *indexInfo)
{
Relation heap = (Relation) PG_GETARG_POINTER(0);
Relation index = (Relation) PG_GETARG_POINTER(1);
IndexInfo *indexInfo = (IndexInfo *) PG_GETARG_POINTER(2);
IndexBuildResult *result;
double reltuples;
BTBuildState buildstate;
@@ -156,7 +197,7 @@ btbuild(PG_FUNCTION_ARGS)
result->heap_tuples = reltuples;
result->index_tuples = buildstate.indtuples;
PG_RETURN_POINTER(result);
return result;
}
/*
@@ -191,10 +232,9 @@ btbuildCallback(Relation index,
/*
* btbuildempty() -- build an empty btree index in the initialization fork
*/
Datum
btbuildempty(PG_FUNCTION_ARGS)
void
btbuildempty(Relation index)
{
Relation index = (Relation) PG_GETARG_POINTER(0);
Page metapage;
/* Construct metapage. */
@@ -215,8 +255,6 @@ btbuildempty(PG_FUNCTION_ARGS)
* checkpoint may have moved the redo pointer past our xlog record.
*/
smgrimmedsync(index->rd_smgr, INIT_FORKNUM);
PG_RETURN_VOID();
}
/*
@@ -225,15 +263,11 @@ btbuildempty(PG_FUNCTION_ARGS)
* Descend the tree recursively, find the appropriate location for our
* new tuple, and put it there.
*/
Datum
btinsert(PG_FUNCTION_ARGS)
bool
btinsert(Relation rel, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique)
{
Relation rel = (Relation) PG_GETARG_POINTER(0);
Datum *values = (Datum *) PG_GETARG_POINTER(1);
bool *isnull = (bool *) PG_GETARG_POINTER(2);
ItemPointer ht_ctid = (ItemPointer) PG_GETARG_POINTER(3);
Relation heapRel = (Relation) PG_GETARG_POINTER(4);
IndexUniqueCheck checkUnique = (IndexUniqueCheck) PG_GETARG_INT32(5);
bool result;
IndexTuple itup;
@@ -245,17 +279,15 @@ btinsert(PG_FUNCTION_ARGS)
pfree(itup);
PG_RETURN_BOOL(result);
return result;
}
/*
* btgettuple() -- Get the next tuple in the scan.
*/
Datum
btgettuple(PG_FUNCTION_ARGS)
bool
btgettuple(IndexScanDesc scan, ScanDirection dir)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
ScanDirection dir = (ScanDirection) PG_GETARG_INT32(1);
BTScanOpaque so = (BTScanOpaque) scan->opaque;
bool res;
@@ -271,7 +303,7 @@ btgettuple(PG_FUNCTION_ARGS)
{
/* punt if we have any unsatisfiable array keys */
if (so->numArrayKeys < 0)
PG_RETURN_BOOL(false);
return false;
_bt_start_array_keys(scan, dir);
}
@@ -321,17 +353,15 @@ btgettuple(PG_FUNCTION_ARGS)
/* ... otherwise see if we have more array keys to deal with */
} while (so->numArrayKeys && _bt_advance_array_keys(scan, dir));
PG_RETURN_BOOL(res);
return res;
}
/*
* btgetbitmap() -- gets all matching tuples, and adds them to a bitmap
*/
Datum
btgetbitmap(PG_FUNCTION_ARGS)
int64
btgetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
TIDBitmap *tbm = (TIDBitmap *) PG_GETARG_POINTER(1);
BTScanOpaque so = (BTScanOpaque) scan->opaque;
int64 ntids = 0;
ItemPointer heapTid;
@@ -343,7 +373,7 @@ btgetbitmap(PG_FUNCTION_ARGS)
{
/* punt if we have any unsatisfiable array keys */
if (so->numArrayKeys < 0)
PG_RETURN_INT64(ntids);
return ntids;
_bt_start_array_keys(scan, ForwardScanDirection);
}
@@ -381,18 +411,15 @@ btgetbitmap(PG_FUNCTION_ARGS)
/* Now see if we have more array keys to deal with */
} while (so->numArrayKeys && _bt_advance_array_keys(scan, ForwardScanDirection));
PG_RETURN_INT64(ntids);
return ntids;
}
/*
* btbeginscan() -- start a scan on a btree index
*/
Datum
btbeginscan(PG_FUNCTION_ARGS)
IndexScanDesc
btbeginscan(Relation rel, int nkeys, int norderbys)
{
Relation rel = (Relation) PG_GETARG_POINTER(0);
int nkeys = PG_GETARG_INT32(1);
int norderbys = PG_GETARG_INT32(2);
IndexScanDesc scan;
BTScanOpaque so;
@@ -430,19 +457,16 @@ btbeginscan(PG_FUNCTION_ARGS)
scan->opaque = so;
PG_RETURN_POINTER(scan);
return scan;
}
/*
* btrescan() -- rescan an index relation
*/
Datum
btrescan(PG_FUNCTION_ARGS)
void
btrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
ScanKey orderbys, int norderbys)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
ScanKey scankey = (ScanKey) PG_GETARG_POINTER(1);
/* remaining arguments are ignored */
BTScanOpaque so = (BTScanOpaque) scan->opaque;
/* we aren't holding any read locks, but gotta drop the pins */
@@ -493,17 +517,14 @@ btrescan(PG_FUNCTION_ARGS)
/* If any keys are SK_SEARCHARRAY type, set up array-key info */
_bt_preprocess_array_keys(scan);
PG_RETURN_VOID();
}
/*
* btendscan() -- close down a scan
*/
Datum
btendscan(PG_FUNCTION_ARGS)
void
btendscan(IndexScanDesc scan)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
BTScanOpaque so = (BTScanOpaque) scan->opaque;
/* we aren't holding any read locks, but gotta drop the pins */
@@ -532,17 +553,14 @@ btendscan(PG_FUNCTION_ARGS)
pfree(so->currTuples);
/* so->markTuples should not be pfree'd, see btrescan */
pfree(so);
PG_RETURN_VOID();
}
/*
* btmarkpos() -- save current scan position
*/
Datum
btmarkpos(PG_FUNCTION_ARGS)
void
btmarkpos(IndexScanDesc scan)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
BTScanOpaque so = (BTScanOpaque) scan->opaque;
/* There may be an old mark with a pin (but no lock). */
@@ -565,17 +583,14 @@ btmarkpos(PG_FUNCTION_ARGS)
/* Also record the current positions of any array keys */
if (so->numArrayKeys)
_bt_mark_array_keys(scan);
PG_RETURN_VOID();
}
/*
* btrestrpos() -- restore scan to last saved position
*/
Datum
btrestrpos(PG_FUNCTION_ARGS)
void
btrestrpos(IndexScanDesc scan)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
BTScanOpaque so = (BTScanOpaque) scan->opaque;
/* Restore the marked positions of any array keys */
@@ -643,8 +658,6 @@ btrestrpos(PG_FUNCTION_ARGS)
else
BTScanPosInvalidate(so->currPos);
}
PG_RETURN_VOID();
}
/*
@@ -654,13 +667,10 @@ btrestrpos(PG_FUNCTION_ARGS)
*
* Result: a palloc'd struct containing statistical info for VACUUM displays.
*/
Datum
btbulkdelete(PG_FUNCTION_ARGS)
IndexBulkDeleteResult *
btbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state)
{
IndexVacuumInfo *info = (IndexVacuumInfo *) PG_GETARG_POINTER(0);
IndexBulkDeleteResult *volatile stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(1);
IndexBulkDeleteCallback callback = (IndexBulkDeleteCallback) PG_GETARG_POINTER(2);
void *callback_state = (void *) PG_GETARG_POINTER(3);
Relation rel = info->index;
BTCycleId cycleid;
@@ -679,7 +689,7 @@ btbulkdelete(PG_FUNCTION_ARGS)
PG_END_ENSURE_ERROR_CLEANUP(_bt_end_vacuum_callback, PointerGetDatum(rel));
_bt_end_vacuum(rel);
PG_RETURN_POINTER(stats);
return stats;
}
/*
@@ -687,15 +697,12 @@ btbulkdelete(PG_FUNCTION_ARGS)
*
* Result: a palloc'd struct containing statistical info for VACUUM displays.
*/
Datum
btvacuumcleanup(PG_FUNCTION_ARGS)
IndexBulkDeleteResult *
btvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
{
IndexVacuumInfo *info = (IndexVacuumInfo *) PG_GETARG_POINTER(0);
IndexBulkDeleteResult *stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(1);
/* No-op in ANALYZE ONLY mode */
if (info->analyze_only)
PG_RETURN_POINTER(stats);
return stats;
/*
* If btbulkdelete was called, we need not do anything, just return the
@@ -727,7 +734,7 @@ btvacuumcleanup(PG_FUNCTION_ARGS)
stats->num_index_tuples = info->num_heap_tuples;
}
PG_RETURN_POINTER(stats);
return stats;
}
/*
@@ -1148,8 +1155,8 @@ restart:
*
* btrees always do, so this is trivial.
*/
Datum
btcanreturn(PG_FUNCTION_ARGS)
bool
btcanreturn(Relation index, int attno)
{
PG_RETURN_BOOL(true);
return true;
}