mirror of
https://github.com/postgres/postgres.git
synced 2025-07-28 23:42:10 +03:00
Add pg_visibility contrib module.
This lets you examine the visibility map as well as page-level visibility information. I initially wrote it as a debugging aid, but was encouraged to polish it for commit. Patch by me, reviewed by Masahiko Sawada. Discussion: 56D77803.6080503@BlueTreble.com
This commit is contained in:
Robert Haas
350
contrib/pg_visibility/pg_visibility.c
Normal file
350
contrib/pg_visibility/pg_visibility.c
Normal file
@ -0,0 +1,350 @@
|
||||
/*-------------------------------------------------------------------------
|
||||
*
|
||||
* pg_visibility.c
|
||||
* display visibility map information and page-level visibility bits
|
||||
*
|
||||
* contrib/pg_visibility/pg_visibility.c
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
#include "postgres.h"
|
||||
|
||||
#include "access/htup_details.h"
|
||||
#include "access/visibilitymap.h"
|
||||
#include "catalog/pg_type.h"
|
||||
#include "funcapi.h"
|
||||
#include "miscadmin.h"
|
||||
#include "storage/bufmgr.h"
|
||||
#include "utils/rel.h"
|
||||
|
||||
PG_MODULE_MAGIC;
|
||||
|
||||
typedef struct vbits
|
||||
{
|
||||
BlockNumber next;
|
||||
BlockNumber count;
|
||||
uint8 bits[FLEXIBLE_ARRAY_MEMBER];
|
||||
} vbits;
|
||||
|
||||
PG_FUNCTION_INFO_V1(pg_visibility_map);
|
||||
PG_FUNCTION_INFO_V1(pg_visibility_map_rel);
|
||||
PG_FUNCTION_INFO_V1(pg_visibility);
|
||||
PG_FUNCTION_INFO_V1(pg_visibility_rel);
|
||||
PG_FUNCTION_INFO_V1(pg_visibility_map_summary);
|
||||
|
||||
static TupleDesc pg_visibility_tupdesc(bool include_blkno, bool include_pd);
|
||||
static vbits *collect_visibility_data(Oid relid, bool include_pd);
|
||||
|
||||
/*
|
||||
* Visibility map information for a single block of a relation.
|
||||
*/
|
||||
Datum
|
||||
pg_visibility_map(PG_FUNCTION_ARGS)
|
||||
{
|
||||
Oid relid = PG_GETARG_OID(0);
|
||||
int64 blkno = PG_GETARG_INT64(1);
|
||||
int32 mapbits;
|
||||
Relation rel;
|
||||
Buffer vmbuffer = InvalidBuffer;
|
||||
TupleDesc tupdesc;
|
||||
Datum values[2];
|
||||
bool nulls[2];
|
||||
|
||||
rel = relation_open(relid, AccessShareLock);
|
||||
|
||||
if (blkno < 0 || blkno > MaxBlockNumber)
|
||||
ereport(ERROR,
|
||||
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
|
||||
errmsg("invalid block number")));
|
||||
|
||||
tupdesc = pg_visibility_tupdesc(false, false);
|
||||
MemSet(nulls, 0, sizeof(nulls));
|
||||
|
||||
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
|
||||
if (vmbuffer != InvalidBuffer)
|
||||
ReleaseBuffer(vmbuffer);
|
||||
values[0] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0);
|
||||
values[1] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0);
|
||||
|
||||
relation_close(rel, AccessShareLock);
|
||||
|
||||
PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
|
||||
}
|
||||
|
||||
/*
|
||||
* Visibility map information for a single block of a relation, plus the
|
||||
* page-level information for the same block.
|
||||
*/
|
||||
Datum
|
||||
pg_visibility(PG_FUNCTION_ARGS)
|
||||
{
|
||||
Oid relid = PG_GETARG_OID(0);
|
||||
int64 blkno = PG_GETARG_INT64(1);
|
||||
int32 mapbits;
|
||||
Relation rel;
|
||||
Buffer vmbuffer = InvalidBuffer;
|
||||
Buffer buffer;
|
||||
Page page;
|
||||
TupleDesc tupdesc;
|
||||
Datum values[3];
|
||||
bool nulls[3];
|
||||
|
||||
rel = relation_open(relid, AccessShareLock);
|
||||
|
||||
if (blkno < 0 || blkno > MaxBlockNumber)
|
||||
ereport(ERROR,
|
||||
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
|
||||
errmsg("invalid block number")));
|
||||
|
||||
tupdesc = pg_visibility_tupdesc(false, true);
|
||||
MemSet(nulls, 0, sizeof(nulls));
|
||||
|
||||
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
|
||||
if (vmbuffer != InvalidBuffer)
|
||||
ReleaseBuffer(vmbuffer);
|
||||
values[0] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0);
|
||||
values[1] = BoolGetDatum((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0);
|
||||
|
||||
buffer = ReadBuffer(rel, blkno);
|
||||
LockBuffer(buffer, BUFFER_LOCK_SHARE);
|
||||
|
||||
page = BufferGetPage(buffer);
|
||||
values[2] = BoolGetDatum(PageIsAllVisible(page));
|
||||
|
||||
UnlockReleaseBuffer(buffer);
|
||||
|
||||
relation_close(rel, AccessShareLock);
|
||||
|
||||
PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
|
||||
}
|
||||
|
||||
/*
|
||||
* Visibility map information for every block in a relation.
|
||||
*/
|
||||
Datum
|
||||
pg_visibility_map_rel(PG_FUNCTION_ARGS)
|
||||
{
|
||||
FuncCallContext *funcctx;
|
||||
vbits *info;
|
||||
|
||||
if (SRF_IS_FIRSTCALL())
|
||||
{
|
||||
Oid relid = PG_GETARG_OID(0);
|
||||
MemoryContext oldcontext;
|
||||
|
||||
funcctx = SRF_FIRSTCALL_INIT();
|
||||
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
|
||||
funcctx->tuple_desc = pg_visibility_tupdesc(true, false);
|
||||
funcctx->user_fctx = collect_visibility_data(relid, false);
|
||||
MemoryContextSwitchTo(oldcontext);
|
||||
}
|
||||
|
||||
funcctx = SRF_PERCALL_SETUP();
|
||||
info = (vbits *) funcctx->user_fctx;
|
||||
|
||||
if (info->next < info->count)
|
||||
{
|
||||
Datum values[3];
|
||||
bool nulls[3];
|
||||
HeapTuple tuple;
|
||||
|
||||
MemSet(nulls, 0, sizeof(nulls));
|
||||
values[0] = Int64GetDatum(info->next);
|
||||
values[1] = BoolGetDatum((info->bits[info->next] & (1 << 0)) != 0);
|
||||
values[2] = BoolGetDatum((info->bits[info->next] & (1 << 1)) != 0);
|
||||
info->next++;
|
||||
|
||||
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
|
||||
SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
|
||||
}
|
||||
|
||||
SRF_RETURN_DONE(funcctx);
|
||||
}
|
||||
|
||||
/*
|
||||
* Visibility map information for every block in a relation, plus the page
|
||||
* level information for each block.
|
||||
*/
|
||||
Datum
|
||||
pg_visibility_rel(PG_FUNCTION_ARGS)
|
||||
{
|
||||
FuncCallContext *funcctx;
|
||||
vbits *info;
|
||||
|
||||
if (SRF_IS_FIRSTCALL())
|
||||
{
|
||||
Oid relid = PG_GETARG_OID(0);
|
||||
MemoryContext oldcontext;
|
||||
|
||||
funcctx = SRF_FIRSTCALL_INIT();
|
||||
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
|
||||
funcctx->tuple_desc = pg_visibility_tupdesc(true, true);
|
||||
funcctx->user_fctx = collect_visibility_data(relid, true);
|
||||
MemoryContextSwitchTo(oldcontext);
|
||||
}
|
||||
|
||||
funcctx = SRF_PERCALL_SETUP();
|
||||
info = (vbits *) funcctx->user_fctx;
|
||||
|
||||
if (info->next < info->count)
|
||||
{
|
||||
Datum values[4];
|
||||
bool nulls[4];
|
||||
HeapTuple tuple;
|
||||
|
||||
MemSet(nulls, 0, sizeof(nulls));
|
||||
values[0] = Int64GetDatum(info->next);
|
||||
values[1] = BoolGetDatum((info->bits[info->next] & (1 << 0)) != 0);
|
||||
values[2] = BoolGetDatum((info->bits[info->next] & (1 << 1)) != 0);
|
||||
values[3] = BoolGetDatum((info->bits[info->next] & (1 << 2)) != 0);
|
||||
info->next++;
|
||||
|
||||
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
|
||||
SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
|
||||
}
|
||||
|
||||
SRF_RETURN_DONE(funcctx);
|
||||
}
|
||||
|
||||
/*
|
||||
* Count the number of all-visible and all-frozen pages in the visibility
|
||||
* map for a particular relation.
|
||||
*/
|
||||
Datum
|
||||
pg_visibility_map_summary(PG_FUNCTION_ARGS)
|
||||
{
|
||||
Oid relid = PG_GETARG_OID(0);
|
||||
Relation rel;
|
||||
BlockNumber nblocks;
|
||||
BlockNumber blkno;
|
||||
Buffer vmbuffer = InvalidBuffer;
|
||||
int64 all_visible = 0;
|
||||
int64 all_frozen = 0;
|
||||
TupleDesc tupdesc;
|
||||
Datum values[2];
|
||||
bool nulls[2];
|
||||
|
||||
rel = relation_open(relid, AccessShareLock);
|
||||
nblocks = RelationGetNumberOfBlocks(rel);
|
||||
|
||||
for (blkno = 0; blkno < nblocks; ++blkno)
|
||||
{
|
||||
int32 mapbits;
|
||||
|
||||
/* Make sure we are interruptible. */
|
||||
CHECK_FOR_INTERRUPTS();
|
||||
|
||||
/* Get map info. */
|
||||
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
|
||||
if ((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0)
|
||||
++all_visible;
|
||||
if ((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0)
|
||||
++all_frozen;
|
||||
}
|
||||
|
||||
/* Clean up. */
|
||||
if (vmbuffer != InvalidBuffer)
|
||||
ReleaseBuffer(vmbuffer);
|
||||
relation_close(rel, AccessShareLock);
|
||||
|
||||
tupdesc = CreateTemplateTupleDesc(2, false);
|
||||
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "all_visible", INT8OID, -1, 0);
|
||||
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "all_frozen", INT8OID, -1, 0);
|
||||
tupdesc = BlessTupleDesc(tupdesc);
|
||||
|
||||
MemSet(nulls, 0, sizeof(nulls));
|
||||
values[0] = Int64GetDatum(all_visible);
|
||||
values[1] = Int64GetDatum(all_frozen);
|
||||
|
||||
PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
|
||||
}
|
||||
|
||||
/*
|
||||
* Helper function to construct whichever TupleDesc we need for a particular
|
||||
* call.
|
||||
*/
|
||||
static TupleDesc
|
||||
pg_visibility_tupdesc(bool include_blkno, bool include_pd)
|
||||
{
|
||||
TupleDesc tupdesc;
|
||||
AttrNumber maxattr = 2;
|
||||
AttrNumber a = 0;
|
||||
|
||||
if (include_blkno)
|
||||
++maxattr;
|
||||
if (include_pd)
|
||||
++maxattr;
|
||||
tupdesc = CreateTemplateTupleDesc(maxattr, false);
|
||||
if (include_blkno)
|
||||
TupleDescInitEntry(tupdesc, ++a, "blkno", INT8OID, -1, 0);
|
||||
TupleDescInitEntry(tupdesc, ++a, "all_visible", BOOLOID, -1, 0);
|
||||
TupleDescInitEntry(tupdesc, ++a, "all_frozen", BOOLOID, -1, 0);
|
||||
if (include_pd)
|
||||
TupleDescInitEntry(tupdesc, ++a, "pd_all_visible", BOOLOID, -1, 0);
|
||||
Assert(a == maxattr);
|
||||
|
||||
return BlessTupleDesc(tupdesc);
|
||||
}
|
||||
|
||||
/*
|
||||
* Collect visibility data about a relation.
|
||||
*/
|
||||
static vbits *
|
||||
collect_visibility_data(Oid relid, bool include_pd)
|
||||
{
|
||||
Relation rel;
|
||||
BlockNumber nblocks;
|
||||
vbits *info;
|
||||
BlockNumber blkno;
|
||||
Buffer vmbuffer = InvalidBuffer;
|
||||
BufferAccessStrategy bstrategy = GetAccessStrategy(BAS_BULKREAD);
|
||||
|
||||
rel = relation_open(relid, AccessShareLock);
|
||||
|
||||
nblocks = RelationGetNumberOfBlocks(rel);
|
||||
info = palloc0(offsetof(vbits, bits) + nblocks);
|
||||
info->next = 0;
|
||||
info->count = nblocks;
|
||||
|
||||
for (blkno = 0; blkno < nblocks; ++blkno)
|
||||
{
|
||||
int32 mapbits;
|
||||
|
||||
/* Make sure we are interruptible. */
|
||||
CHECK_FOR_INTERRUPTS();
|
||||
|
||||
/* Get map info. */
|
||||
mapbits = (int32) visibilitymap_get_status(rel, blkno, &vmbuffer);
|
||||
if ((mapbits & VISIBILITYMAP_ALL_VISIBLE) != 0)
|
||||
info->bits[blkno] |= (1 << 0);
|
||||
if ((mapbits & VISIBILITYMAP_ALL_FROZEN) != 0)
|
||||
info->bits[blkno] |= (1 << 1);
|
||||
|
||||
/*
|
||||
* Page-level data requires reading every block, so only get it if
|
||||
* the caller needs it. Use a buffer access strategy, too, to prevent
|
||||
* cache-trashing.
|
||||
*/
|
||||
if (include_pd)
|
||||
{
|
||||
Buffer buffer;
|
||||
Page page;
|
||||
|
||||
buffer = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL,
|
||||
bstrategy);
|
||||
LockBuffer(buffer, BUFFER_LOCK_SHARE);
|
||||
|
||||
page = BufferGetPage(buffer);
|
||||
if (PageIsAllVisible(page))
|
||||
info->bits[blkno] |= (1 << 2);
|
||||
|
||||
UnlockReleaseBuffer(buffer);
|
||||
}
|
||||
}
|
||||
|
||||
/* Clean up. */
|
||||
if (vmbuffer != InvalidBuffer)
|
||||
ReleaseBuffer(vmbuffer);
|
||||
relation_close(rel, AccessShareLock);
|
||||
|
||||
return info;
|
||||
}
|
||||
Reference in New Issue
Block a user