Tom Lane wrote:
However, we did learn something valuable from the fact that all the
-DCLOBBER_CACHE_ALWAYS critters failed on it: per my earlier message,
brin_page_items() is unsafe against a relcache flush on the index.
I'll put that on the 9.5 open items list.
(If I were tasked with fixing it, I'd be tempted to rewrite it to do
all the work in one call and return a tuplestore; the alternative
seems to be to try to keep the index open across multiple calls,
which would be a mess.)
Here's a patch doing that.
--
Álvaro Herrerahttp://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training Services
commit 41eba17795e9cf9b0c23e05def5d33b0dbdd4807[m
Author: Alvaro Herrera alvhe...@alvh.no-ip.org
AuthorDate: Wed Aug 12 15:41:15 2015 -0300
CommitDate: Wed Aug 12 15:41:15 2015 -0300
fix brin_page_items to use a tuplestore
diff --git a/contrib/pageinspect/brinfuncs.c b/contrib/pageinspect/brinfuncs.c
index 7adcfa8..f695b18 100644
--- a/contrib/pageinspect/brinfuncs.c
+++ b/contrib/pageinspect/brinfuncs.c
@@ -37,18 +37,6 @@ typedef struct brin_column_state
FmgrInfo outputFn[FLEXIBLE_ARRAY_MEMBER];
} brin_column_state;
-typedef struct brin_page_state
-{
- BrinDesc *bdesc;
- Page page;
- OffsetNumber offset;
- bool unusedItem;
- bool done;
- AttrNumber attno;
- BrinMemTuple *dtup;
- brin_column_state *columns[FLEXIBLE_ARRAY_MEMBER];
-} brin_page_state;
-
static Page verify_brin_page(bytea *raw_page, uint16 type,
const char *strtype);
@@ -119,89 +107,90 @@ verify_brin_page(bytea *raw_page, uint16 type, const char *strtype)
Datum
brin_page_items(PG_FUNCTION_ARGS)
{
- brin_page_state *state;
- FuncCallContext *fctx;
+ 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;
+ Page page;
+ OffsetNumber offset;
+ AttrNumber attno;
+ bool unusedItem;
+ BrinDesc *bdesc;
+ BrinMemTuple *dtup;
+ brin_column_state **columns;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg(must be superuser to use raw page functions;
- if (SRF_IS_FIRSTCALL())
+ /* 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);
+
+ /* minimally verify the page we got */
+ page = verify_brin_page(raw_page, BRIN_PAGETYPE_REGULAR, regular);
+
+ bdesc = brin_build_desc(indexRel);
+ offset = FirstOffsetNumber;
+ unusedItem = false;
+ dtup = NULL;
+
+ /*
+ * 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++)
{
- bytea *raw_page = PG_GETARG_BYTEA_P(0);
- Oid indexRelid = PG_GETARG_OID(1);
- Page page;
- TupleDesc tupdesc;
- MemoryContext mctx;
- Relation indexRel;
- AttrNumber attno;
+ Oid output;
+ bool isVarlena;
+ BrinOpcInfo *opcinfo;
+ int i;
+ brin_column_state *column;
- /* minimally verify the page we got */
- page = verify_brin_page(raw_page, BRIN_PAGETYPE_REGULAR, regular);
+ opcinfo = bdesc-bd_info[attno - 1];
+ column = palloc(offsetof(brin_column_state, outputFn) +
+ sizeof(FmgrInfo) * opcinfo-oi_nstored);
- /* 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 =
