/*
* Initialize state for a BRIN index scan.
*
* We read the metapage here to determine the pages-per-range number that this
* index was built with. Note that since this cannot be changed while we're
* holding lock on index, it's not necessary to recompute it during brinrescan.
*/
IndexScanDesc
brinbeginscan(Relation r, int nkeys, int norderbys)
{
IndexScanDesc scan;
BrinOpaque *opaque;
scan = RelationGetIndexScan(r, nkeys, norderbys);
opaque = (BrinOpaque *) palloc(sizeof(BrinOpaque));
opaque->bo_rmAccess = brinRevmapInitialize(r, &opaque->bo_pagesPerRange,
scan->xs_snapshot);
opaque->bo_bdesc = brin_build_desc(r);
scan->opaque = opaque;
return scan;
}
/*
* Initialize state for a BRIN index scan.
*
* We read the metapage here to determine the pages-per-range number that this
* index was built with. Note that since this cannot be changed while we're
* holding lock on index, it's not necessary to recompute it during brinrescan.
*/
Datum
brinbeginscan(PG_FUNCTION_ARGS)
{
Relation r = (Relation) PG_GETARG_POINTER(0);
int nkeys = PG_GETARG_INT32(1);
int norderbys = PG_GETARG_INT32(2);
IndexScanDesc scan;
BrinOpaque *opaque;
scan = RelationGetIndexScan(r, nkeys, norderbys);
opaque = (BrinOpaque *) palloc(sizeof(BrinOpaque));
opaque->bo_rmAccess = brinRevmapInitialize(r, &opaque->bo_pagesPerRange);
opaque->bo_bdesc = brin_build_desc(r);
scan->opaque = opaque;
PG_RETURN_POINTER(scan);
}
/*
* Initialize a BrinBuildState appropriate to create tuples on the given index.
*/
static BrinBuildState *
initialize_brin_buildstate(Relation idxRel, BrinRevmap *revmap,
BlockNumber pagesPerRange)
{
BrinBuildState *state;
state = palloc(sizeof(BrinBuildState));
state->bs_irel = idxRel;
state->bs_numtuples = 0;
state->bs_currentInsertBuf = InvalidBuffer;
state->bs_pagesPerRange = pagesPerRange;
state->bs_currRangeStart = 0;
state->bs_rmAccess = revmap;
state->bs_bdesc = brin_build_desc(idxRel);
state->bs_dtuple = brin_new_memtuple(state->bs_bdesc);
brin_memtuple_initialize(state->bs_dtuple, state->bs_bdesc);
return state;
}
/*
* Extract all item values from a BRIN index page
*
* Usage: SELECT * FROM brin_page_items(get_raw_page('idx', 1), 'idx'::regclass);
*/
Datum
brin_page_items(PG_FUNCTION_ARGS)
{
bytea *raw_page = PG_GETARG_BYTEA_P(0);
Oid indexRelid = PG_GETARG_OID(1);
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
MemoryContext oldcontext;
Tuplestorestate *tupstore;
Relation indexRel;
brin_column_state **columns;
BrinDesc *bdesc;
BrinMemTuple *dtup;
Page page;
OffsetNumber offset;
AttrNumber attno;
bool unusedItem;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to use raw page functions"))));
/* check to see if caller supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize) ||
rsinfo->expectedDesc == NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not allowed in this context")));
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
/* Build tuplestore to hold the result rows */
oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(true, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
indexRel = index_open(indexRelid, AccessShareLock);
bdesc = brin_build_desc(indexRel);
/* minimally verify the page we got */
page = verify_brin_page(raw_page, BRIN_PAGETYPE_REGULAR, "regular");
/*
* Initialize output functions for all indexed datatypes; simplifies
* calling them later.
*/
columns = palloc(sizeof(brin_column_state *) * RelationGetDescr(indexRel)->natts);
for (attno = 1; attno <= bdesc->bd_tupdesc->natts; attno++)
{
Oid output;
bool isVarlena;
BrinOpcInfo *opcinfo;
int i;
brin_column_state *column;
opcinfo = bdesc->bd_info[attno - 1];
column = palloc(offsetof(brin_column_state, outputFn) +
sizeof(FmgrInfo) * opcinfo->oi_nstored);
column->nstored = opcinfo->oi_nstored;
for (i = 0; i < opcinfo->oi_nstored; i++)
{
getTypeOutputInfo(opcinfo->oi_typcache[i]->type_id, &output, &isVarlena);
fmgr_info(output, &column->outputFn[i]);
}
columns[attno - 1] = column;
}
offset = FirstOffsetNumber;
unusedItem = false;
dtup = NULL;
for (;;)
{
Datum values[7];
bool nulls[7];
/*
* This loop is called once for every attribute of every tuple in the
* page. At the start of a tuple, we get a NULL dtup; that's our
* signal for obtaining and decoding the next one. If that's not the
* case, we output the next attribute.
*/
if (dtup == NULL)
{
ItemId itemId;
/* verify item status: if there's no data, we can't decode */
itemId = PageGetItemId(page, offset);
if (ItemIdIsUsed(itemId))
{
dtup = brin_deform_tuple(bdesc,
(BrinTuple *) PageGetItem(page, itemId));
attno = 1;
unusedItem = false;
}
else
unusedItem = true;
}
else
attno++;
MemSet(nulls, 0, sizeof(nulls));
if (unusedItem)
{
values[0] = UInt16GetDatum(offset);
nulls[1] = true;
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
}
else
{
int att = attno - 1;
values[0] = UInt16GetDatum(offset);
values[1] = UInt32GetDatum(dtup->bt_blkno);
values[2] = UInt16GetDatum(attno);
values[3] = BoolGetDatum(dtup->bt_columns[att].bv_allnulls);
values[4] = BoolGetDatum(dtup->bt_columns[att].bv_hasnulls);
values[5] = BoolGetDatum(dtup->bt_placeholder);
if (!dtup->bt_columns[att].bv_allnulls)
{
BrinValues *bvalues = &dtup->bt_columns[att];
StringInfoData s;
bool first;
int i;
initStringInfo(&s);
appendStringInfoChar(&s, '{');
first = true;
for (i = 0; i < columns[att]->nstored; i++)
{
char *val;
if (!first)
appendStringInfoString(&s, " .. ");
first = false;
val = OutputFunctionCall(&columns[att]->outputFn[i],
bvalues->bv_values[i]);
appendStringInfoString(&s, val);
pfree(val);
}
appendStringInfoChar(&s, '}');
values[6] = CStringGetTextDatum(s.data);
pfree(s.data);
}
else
{
nulls[6] = true;
}
}
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
/*
* If the item was unused, jump straight to the next one; otherwise,
* the only cleanup needed here is to set our signal to go to the next
* tuple in the following iteration, by freeing the current one.
*/
if (unusedItem)
offset = OffsetNumberNext(offset);
else if (attno >= bdesc->bd_tupdesc->natts)
{
pfree(dtup);
dtup = NULL;
offset = OffsetNumberNext(offset);
}
/*
* If we're beyond the end of the page, we're done.
*/
if (offset > PageGetMaxOffsetNumber(page))
break;
}
/* clean up and return the tuplestore */
brin_free_desc(bdesc);
tuplestore_donestoring(tupstore);
index_close(indexRel, AccessShareLock);
return (Datum) 0;
}
/*
* A tuple in the heap is being inserted. To keep a brin index up to date,
* we need to obtain the relevant index tuple and compare its stored values
* with those of the new tuple. If the tuple values are not consistent with
* the summary tuple, we need to update the index tuple.
*
* If the range is not currently summarized (i.e. the revmap returns NULL for
* it), there's nothing to do.
*/
bool
brininsert(Relation idxRel, Datum *values, bool *nulls,
ItemPointer heaptid, Relation heapRel,
IndexUniqueCheck checkUnique)
{
BlockNumber pagesPerRange;
BrinDesc *bdesc = NULL;
BrinRevmap *revmap;
Buffer buf = InvalidBuffer;
MemoryContext tupcxt = NULL;
MemoryContext oldcxt = NULL;
revmap = brinRevmapInitialize(idxRel, &pagesPerRange, NULL);
for (;;)
{
bool need_insert = false;
OffsetNumber off;
BrinTuple *brtup;
BrinMemTuple *dtup;
BlockNumber heapBlk;
int keyno;
CHECK_FOR_INTERRUPTS();
heapBlk = ItemPointerGetBlockNumber(heaptid);
/* normalize the block number to be the first block in the range */
heapBlk = (heapBlk / pagesPerRange) * pagesPerRange;
brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off, NULL,
BUFFER_LOCK_SHARE, NULL);
/* if range is unsummarized, there's nothing to do */
if (!brtup)
break;
/* First time through? */
if (bdesc == NULL)
{
bdesc = brin_build_desc(idxRel);
tupcxt = AllocSetContextCreate(CurrentMemoryContext,
"brininsert cxt",
ALLOCSET_DEFAULT_SIZES);
oldcxt = MemoryContextSwitchTo(tupcxt);
}
dtup = brin_deform_tuple(bdesc, brtup);
/*
* Compare the key values of the new tuple to the stored index values;
* our deformed tuple will get updated if the new tuple doesn't fit
* the original range (note this means we can't break out of the loop
* early). Make a note of whether this happens, so that we know to
* insert the modified tuple later.
*/
for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
{
Datum result;
BrinValues *bval;
FmgrInfo *addValue;
bval = &dtup->bt_columns[keyno];
addValue = index_getprocinfo(idxRel, keyno + 1,
BRIN_PROCNUM_ADDVALUE);
result = FunctionCall4Coll(addValue,
idxRel->rd_indcollation[keyno],
PointerGetDatum(bdesc),
PointerGetDatum(bval),
values[keyno],
nulls[keyno]);
/* if that returned true, we need to insert the updated tuple */
need_insert |= DatumGetBool(result);
}
if (!need_insert)
{
/*
* The tuple is consistent with the new values, so there's nothing
* to do.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
else
{
Page page = BufferGetPage(buf);
ItemId lp = PageGetItemId(page, off);
Size origsz;
BrinTuple *origtup;
Size newsz;
BrinTuple *newtup;
bool samepage;
/*
* Make a copy of the old tuple, so that we can compare it after
* re-acquiring the lock.
*/
origsz = ItemIdGetLength(lp);
origtup = brin_copy_tuple(brtup, origsz);
/*
* Before releasing the lock, check if we can attempt a same-page
* update. Another process could insert a tuple concurrently in
* the same page though, so downstream we must be prepared to cope
* if this turns out to not be possible after all.
*/
newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
samepage = brin_can_do_samepage_update(buf, origsz, newsz);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/*
* Try to update the tuple. If this doesn't work for whatever
* reason, we need to restart from the top; the revmap might be
* pointing at a different tuple for this block now, so we need to
* recompute to ensure both our new heap tuple and the other
* inserter's are covered by the combined tuple. It might be that
* we don't need to update at all.
*/
if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
buf, off, origtup, origsz, newtup, newsz,
samepage))
{
/* no luck; start over */
MemoryContextResetAndDeleteChildren(tupcxt);
continue;
}
}
/* success! */
break;
}
brinRevmapTerminate(revmap);
if (BufferIsValid(buf))
ReleaseBuffer(buf);
if (bdesc != NULL)
{
brin_free_desc(bdesc);
MemoryContextSwitchTo(oldcxt);
MemoryContextDelete(tupcxt);
}
return false;
}
/*
* A tuple in the heap is being inserted. To keep a brin index up to date,
* we need to obtain the relevant index tuple and compare its stored values
* with those of the new tuple. If the tuple values are not consistent with
* the summary tuple, we need to update the index tuple.
*
* If the range is not currently summarized (i.e. the revmap returns NULL for
* it), there's nothing to do.
*/
Datum
brininsert(PG_FUNCTION_ARGS)
{
Relation idxRel = (Relation) PG_GETARG_POINTER(0);
Datum *values = (Datum *) PG_GETARG_POINTER(1);
bool *nulls = (bool *) PG_GETARG_POINTER(2);
ItemPointer heaptid = (ItemPointer) PG_GETARG_POINTER(3);
/* we ignore the rest of our arguments */
BlockNumber pagesPerRange;
BrinDesc *bdesc = NULL;
BrinRevmap *revmap;
Buffer buf = InvalidBuffer;
MemoryContext tupcxt = NULL;
MemoryContext oldcxt = NULL;
revmap = brinRevmapInitialize(idxRel, &pagesPerRange);
for (;;)
{
bool need_insert = false;
OffsetNumber off;
BrinTuple *brtup;
BrinMemTuple *dtup;
BlockNumber heapBlk;
int keyno;
#ifdef USE_ASSERT_CHECKING
BrinTuple *tmptup;
BrinMemTuple *tmpdtup;
Size tmpsiz;
#endif
CHECK_FOR_INTERRUPTS();
heapBlk = ItemPointerGetBlockNumber(heaptid);
/* normalize the block number to be the first block in the range */
heapBlk = (heapBlk / pagesPerRange) * pagesPerRange;
brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off, NULL,
BUFFER_LOCK_SHARE);
/* if range is unsummarized, there's nothing to do */
if (!brtup)
break;
/* First time through? */
if (bdesc == NULL)
{
bdesc = brin_build_desc(idxRel);
tupcxt = AllocSetContextCreate(CurrentMemoryContext,
"brininsert cxt",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
oldcxt = MemoryContextSwitchTo(tupcxt);
}
dtup = brin_deform_tuple(bdesc, brtup);
#ifdef USE_ASSERT_CHECKING
{
/*
* When assertions are enabled, we use this as an opportunity to
* test the "union" method, which would otherwise be used very
* rarely: first create a placeholder tuple, and addValue the
* value we just got into it. Then union the existing index tuple
* with the updated placeholder tuple. The tuple resulting from
* that union should be identical to the one resulting from the
* regular operation (straight addValue) below.
*
* Here we create the tuple to compare with; the actual comparison
* is below.
*/
tmptup = brin_form_placeholder_tuple(bdesc, heapBlk, &tmpsiz);
tmpdtup = brin_deform_tuple(bdesc, tmptup);
for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
{
BrinValues *bval;
FmgrInfo *addValue;
bval = &tmpdtup->bt_columns[keyno];
addValue = index_getprocinfo(idxRel, keyno + 1,
BRIN_PROCNUM_ADDVALUE);
FunctionCall4Coll(addValue,
idxRel->rd_indcollation[keyno],
PointerGetDatum(bdesc),
PointerGetDatum(bval),
values[keyno],
nulls[keyno]);
}
union_tuples(bdesc, tmpdtup, brtup);
tmpdtup->bt_placeholder = dtup->bt_placeholder;
tmptup = brin_form_tuple(bdesc, heapBlk, tmpdtup, &tmpsiz);
}
#endif
/*
* Compare the key values of the new tuple to the stored index values;
* our deformed tuple will get updated if the new tuple doesn't fit
* the original range (note this means we can't break out of the loop
* early). Make a note of whether this happens, so that we know to
* insert the modified tuple later.
*/
for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
{
Datum result;
BrinValues *bval;
FmgrInfo *addValue;
bval = &dtup->bt_columns[keyno];
addValue = index_getprocinfo(idxRel, keyno + 1,
BRIN_PROCNUM_ADDVALUE);
result = FunctionCall4Coll(addValue,
idxRel->rd_indcollation[keyno],
PointerGetDatum(bdesc),
PointerGetDatum(bval),
values[keyno],
nulls[keyno]);
/* if that returned true, we need to insert the updated tuple */
need_insert |= DatumGetBool(result);
}
#ifdef USE_ASSERT_CHECKING
{
/*
* Now we can compare the tuple produced by the union function
* with the one from plain addValue.
*/
BrinTuple *cmptup;
Size cmpsz;
cmptup = brin_form_tuple(bdesc, heapBlk, dtup, &cmpsz);
Assert(brin_tuples_equal(tmptup, tmpsiz, cmptup, cmpsz));
}
#endif
if (!need_insert)
{
/*
* The tuple is consistent with the new values, so there's nothing
* to do.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
else
{
Page page = BufferGetPage(buf);
ItemId lp = PageGetItemId(page, off);
Size origsz;
BrinTuple *origtup;
Size newsz;
BrinTuple *newtup;
bool samepage;
/*
* Make a copy of the old tuple, so that we can compare it after
* re-acquiring the lock.
*/
origsz = ItemIdGetLength(lp);
origtup = brin_copy_tuple(brtup, origsz);
/*
* Before releasing the lock, check if we can attempt a same-page
* update. Another process could insert a tuple concurrently in
* the same page though, so downstream we must be prepared to cope
* if this turns out to not be possible after all.
*/
newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
samepage = brin_can_do_samepage_update(buf, origsz, newsz);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/*
* Try to update the tuple. If this doesn't work for whatever
* reason, we need to restart from the top; the revmap might be
* pointing at a different tuple for this block now, so we need to
* recompute to ensure both our new heap tuple and the other
* inserter's are covered by the combined tuple. It might be that
* we don't need to update at all.
*/
if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
buf, off, origtup, origsz, newtup, newsz,
samepage))
{
/* no luck; start over */
MemoryContextResetAndDeleteChildren(tupcxt);
continue;
}
}
/* success! */
break;
}
brinRevmapTerminate(revmap);
if (BufferIsValid(buf))
ReleaseBuffer(buf);
if (bdesc != NULL)
{
brin_free_desc(bdesc);
MemoryContextSwitchTo(oldcxt);
MemoryContextDelete(tupcxt);
}
return BoolGetDatum(false);
}
/*
* Extract all item values from a BRIN index page
*
* Usage: SELECT * FROM brin_page_items(get_raw_page('idx', 1), 'idx'::regclass);
*/
Datum
brin_page_items(PG_FUNCTION_ARGS)
{
brin_page_state *state;
FuncCallContext *fctx;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to use raw page functions"))));
if (SRF_IS_FIRSTCALL())
{
bytea *raw_page = PG_GETARG_BYTEA_P(0);
Oid indexRelid = PG_GETARG_OID(1);
Page page;
TupleDesc tupdesc;
MemoryContext mctx;
Relation indexRel;
AttrNumber attno;
/* minimally verify the page we got */
page = verify_brin_page(raw_page, BRIN_PAGETYPE_REGULAR, "regular");
/* create a function context for cross-call persistence */
fctx = SRF_FIRSTCALL_INIT();
/* switch to memory context appropriate for multiple function calls */
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
indexRel = index_open(indexRelid, AccessShareLock);
state = palloc(offsetof(brin_page_state, columns) +
sizeof(brin_column_state) * RelationGetDescr(indexRel)->natts);
state->bdesc = brin_build_desc(indexRel);
state->page = page;
state->offset = FirstOffsetNumber;
state->unusedItem = false;
state->done = false;
state->dtup = NULL;
/*
* Initialize output functions for all indexed datatypes; simplifies
* calling them later.
*/
for (attno = 1; attno <= state->bdesc->bd_tupdesc->natts; attno++)
{
Oid output;
bool isVarlena;
BrinOpcInfo *opcinfo;
int i;
brin_column_state *column;
opcinfo = state->bdesc->bd_info[attno - 1];
column = palloc(offsetof(brin_column_state, outputFn) +
sizeof(FmgrInfo) * opcinfo->oi_nstored);
column->nstored = opcinfo->oi_nstored;
for (i = 0; i < opcinfo->oi_nstored; i++)
{
getTypeOutputInfo(opcinfo->oi_typcache[i]->type_id, &output, &isVarlena);
fmgr_info(output, &column->outputFn[i]);
}
state->columns[attno - 1] = column;
}
index_close(indexRel, AccessShareLock);
fctx->user_fctx = state;
fctx->tuple_desc = BlessTupleDesc(tupdesc);
MemoryContextSwitchTo(mctx);
}
fctx = SRF_PERCALL_SETUP();
state = fctx->user_fctx;
if (!state->done)
{
HeapTuple result;
Datum values[7];
bool nulls[7];
/*
* This loop is called once for every attribute of every tuple in the
* page. At the start of a tuple, we get a NULL dtup; that's our
* signal for obtaining and decoding the next one. If that's not the
* case, we output the next attribute.
*/
if (state->dtup == NULL)
{
BrinTuple *tup;
MemoryContext mctx;
ItemId itemId;
/* deformed tuple must live across calls */
mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
/* verify item status: if there's no data, we can't decode */
itemId = PageGetItemId(state->page, state->offset);
if (ItemIdIsUsed(itemId))
{
tup = (BrinTuple *) PageGetItem(state->page,
PageGetItemId(state->page,
state->offset));
state->dtup = brin_deform_tuple(state->bdesc, tup);
state->attno = 1;
state->unusedItem = false;
}
else
state->unusedItem = true;
MemoryContextSwitchTo(mctx);
}
else
state->attno++;
MemSet(nulls, 0, sizeof(nulls));
if (state->unusedItem)
{
values[0] = UInt16GetDatum(state->offset);
nulls[1] = true;
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
}
else
{
int att = state->attno - 1;
values[0] = UInt16GetDatum(state->offset);
values[1] = UInt32GetDatum(state->dtup->bt_blkno);
values[2] = UInt16GetDatum(state->attno);
values[3] = BoolGetDatum(state->dtup->bt_columns[att].bv_allnulls);
values[4] = BoolGetDatum(state->dtup->bt_columns[att].bv_hasnulls);
values[5] = BoolGetDatum(state->dtup->bt_placeholder);
if (!state->dtup->bt_columns[att].bv_allnulls)
{
BrinValues *bvalues = &state->dtup->bt_columns[att];
StringInfoData s;
bool first;
int i;
initStringInfo(&s);
appendStringInfoChar(&s, '{');
first = true;
for (i = 0; i < state->columns[att]->nstored; i++)
{
char *val;
if (!first)
appendStringInfoString(&s, " .. ");
first = false;
val = OutputFunctionCall(&state->columns[att]->outputFn[i],
bvalues->bv_values[i]);
appendStringInfoString(&s, val);
pfree(val);
}
appendStringInfoChar(&s, '}');
values[6] = CStringGetTextDatum(s.data);
pfree(s.data);
}
else
{
nulls[6] = true;
}
}
result = heap_form_tuple(fctx->tuple_desc, values, nulls);
/*
* If the item was unused, jump straight to the next one; otherwise,
* the only cleanup needed here is to set our signal to go to the next
* tuple in the following iteration, by freeing the current one.
*/
if (state->unusedItem)
state->offset = OffsetNumberNext(state->offset);
else if (state->attno >= state->bdesc->bd_tupdesc->natts)
{
pfree(state->dtup);
state->dtup = NULL;
state->offset = OffsetNumberNext(state->offset);
}
/*
* If we're beyond the end of the page, set flag to end the function
* in the following iteration.
*/
if (state->offset > PageGetMaxOffsetNumber(state->page))
state->done = true;
SRF_RETURN_NEXT(fctx, HeapTupleGetDatum(result));
}
brin_free_desc(state->bdesc);
SRF_RETURN_DONE(fctx);
}
/*
* A tuple in the heap is being inserted. To keep a brin index up to date,
* we need to obtain the relevant index tuple and compare its stored values
* with those of the new tuple. If the tuple values are not consistent with
* the summary tuple, we need to update the index tuple.
*
* If autosummarization is enabled, check if we need to summarize the previous
* page range.
*
* If the range is not currently summarized (i.e. the revmap returns NULL for
* it), there's nothing to do for this tuple.
*/
bool
brininsert(Relation idxRel, Datum *values, bool *nulls,
ItemPointer heaptid, Relation heapRel,
IndexUniqueCheck checkUnique,
IndexInfo *indexInfo)
{
BlockNumber pagesPerRange;
BlockNumber origHeapBlk;
BlockNumber heapBlk;
BrinDesc *bdesc = (BrinDesc *) indexInfo->ii_AmCache;
BrinRevmap *revmap;
Buffer buf = InvalidBuffer;
MemoryContext tupcxt = NULL;
MemoryContext oldcxt = CurrentMemoryContext;
bool autosummarize = BrinGetAutoSummarize(idxRel);
revmap = brinRevmapInitialize(idxRel, &pagesPerRange, NULL);
/*
* origHeapBlk is the block number where the insertion occurred. heapBlk
* is the first block in the corresponding page range.
*/
origHeapBlk = ItemPointerGetBlockNumber(heaptid);
heapBlk = (origHeapBlk / pagesPerRange) * pagesPerRange;
for (;;)
{
bool need_insert = false;
OffsetNumber off;
BrinTuple *brtup;
BrinMemTuple *dtup;
int keyno;
CHECK_FOR_INTERRUPTS();
/*
* If auto-summarization is enabled and we just inserted the first
* tuple into the first block of a new non-first page range, request a
* summarization run of the previous range.
*/
if (autosummarize &&
heapBlk > 0 &&
heapBlk == origHeapBlk &&
ItemPointerGetOffsetNumber(heaptid) == FirstOffsetNumber)
{
BlockNumber lastPageRange = heapBlk - 1;
BrinTuple *lastPageTuple;
lastPageTuple =
brinGetTupleForHeapBlock(revmap, lastPageRange, &buf, &off,
NULL, BUFFER_LOCK_SHARE, NULL);
if (!lastPageTuple)
{
bool recorded;
recorded = AutoVacuumRequestWork(AVW_BRINSummarizeRange,
RelationGetRelid(idxRel),
lastPageRange);
if (!recorded)
ereport(LOG,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("request for BRIN range summarization for index \"%s\" page %u was not recorded",
RelationGetRelationName(idxRel),
lastPageRange)));
}
else
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off,
NULL, BUFFER_LOCK_SHARE, NULL);
/* if range is unsummarized, there's nothing to do */
if (!brtup)
break;
/* First time through in this statement? */
if (bdesc == NULL)
{
MemoryContextSwitchTo(indexInfo->ii_Context);
bdesc = brin_build_desc(idxRel);
indexInfo->ii_AmCache = (void *) bdesc;
MemoryContextSwitchTo(oldcxt);
}
/* First time through in this brininsert call? */
if (tupcxt == NULL)
{
tupcxt = AllocSetContextCreate(CurrentMemoryContext,
"brininsert cxt",
ALLOCSET_DEFAULT_SIZES);
MemoryContextSwitchTo(tupcxt);
}
dtup = brin_deform_tuple(bdesc, brtup, NULL);
/*
* Compare the key values of the new tuple to the stored index values;
* our deformed tuple will get updated if the new tuple doesn't fit
* the original range (note this means we can't break out of the loop
* early). Make a note of whether this happens, so that we know to
* insert the modified tuple later.
*/
for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
{
Datum result;
BrinValues *bval;
FmgrInfo *addValue;
bval = &dtup->bt_columns[keyno];
addValue = index_getprocinfo(idxRel, keyno + 1,
BRIN_PROCNUM_ADDVALUE);
result = FunctionCall4Coll(addValue,
idxRel->rd_indcollation[keyno],
PointerGetDatum(bdesc),
PointerGetDatum(bval),
values[keyno],
nulls[keyno]);
/* if that returned true, we need to insert the updated tuple */
need_insert |= DatumGetBool(result);
}
if (!need_insert)
{
/*
* The tuple is consistent with the new values, so there's nothing
* to do.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
else
{
Page page = BufferGetPage(buf);
ItemId lp = PageGetItemId(page, off);
Size origsz;
BrinTuple *origtup;
Size newsz;
BrinTuple *newtup;
bool samepage;
/*
* Make a copy of the old tuple, so that we can compare it after
* re-acquiring the lock.
*/
origsz = ItemIdGetLength(lp);
origtup = brin_copy_tuple(brtup, origsz, NULL, NULL);
/*
* Before releasing the lock, check if we can attempt a same-page
* update. Another process could insert a tuple concurrently in
* the same page though, so downstream we must be prepared to cope
* if this turns out to not be possible after all.
*/
newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
samepage = brin_can_do_samepage_update(buf, origsz, newsz);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
/*
* Try to update the tuple. If this doesn't work for whatever
* reason, we need to restart from the top; the revmap might be
* pointing at a different tuple for this block now, so we need to
* recompute to ensure both our new heap tuple and the other
* inserter's are covered by the combined tuple. It might be that
* we don't need to update at all.
*/
if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
buf, off, origtup, origsz, newtup, newsz,
samepage))
{
/* no luck; start over */
MemoryContextResetAndDeleteChildren(tupcxt);
continue;
}
}
/* success! */
break;
}
brinRevmapTerminate(revmap);
if (BufferIsValid(buf))
ReleaseBuffer(buf);
MemoryContextSwitchTo(oldcxt);
if (tupcxt != NULL)
MemoryContextDelete(tupcxt);
return false;
}
