From 65c5fcd353a859da9e61bfb2b92a99f12937de3b Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 17 Jan 2016 19:36:59 -0500 Subject: Restructure index access method API to hide most of it at the C level. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. --- src/backend/access/gist/gistget.c | 35 ++++++++++++++--------------------- 1 file changed, 14 insertions(+), 21 deletions(-) (limited to 'src/backend/access/gist/gistget.c') diff --git a/src/backend/access/gist/gistget.c b/src/backend/access/gist/gistget.c index 21f9de511ff..41b83431b61 100644 --- a/src/backend/access/gist/gistget.c +++ b/src/backend/access/gist/gistget.c @@ -618,18 +618,16 @@ getNextNearest(IndexScanDesc scan) /* * gistgettuple() -- Get the next tuple in the scan */ -Datum -gistgettuple(PG_FUNCTION_ARGS) +bool +gistgettuple(IndexScanDesc scan, ScanDirection dir) { - IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0); - ScanDirection dir = (ScanDirection) PG_GETARG_INT32(1); GISTScanOpaque so = (GISTScanOpaque) scan->opaque; if (dir != ForwardScanDirection) elog(ERROR, "GiST only supports forward scan direction"); if (!so->qual_ok) - PG_RETURN_BOOL(false); + return false; if (so->firstCall) { @@ -651,7 +649,7 @@ gistgettuple(PG_FUNCTION_ARGS) if (scan->numberOfOrderBys > 0) { /* Must fetch tuples in strict distance order */ - PG_RETURN_BOOL(getNextNearest(scan)); + return getNextNearest(scan); } else { @@ -688,7 +686,7 @@ gistgettuple(PG_FUNCTION_ARGS) so->curPageData++; - PG_RETURN_BOOL(true); + return true; } /* @@ -726,7 +724,7 @@ gistgettuple(PG_FUNCTION_ARGS) item = getNextGISTSearchItem(so); if (!item) - PG_RETURN_BOOL(false); + return false; CHECK_FOR_INTERRUPTS(); @@ -750,17 +748,15 @@ gistgettuple(PG_FUNCTION_ARGS) /* * gistgetbitmap() -- Get a bitmap of all heap tuple locations */ -Datum -gistgetbitmap(PG_FUNCTION_ARGS) +int64 +gistgetbitmap(IndexScanDesc scan, TIDBitmap *tbm) { - IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0); - TIDBitmap *tbm = (TIDBitmap *) PG_GETARG_POINTER(1); GISTScanOpaque so = (GISTScanOpaque) scan->opaque; int64 ntids = 0; GISTSearchItem fakeItem; if (!so->qual_ok) - PG_RETURN_INT64(0); + return 0; pgstat_count_index_scan(scan->indexRelation); @@ -791,7 +787,7 @@ gistgetbitmap(PG_FUNCTION_ARGS) pfree(item); } - PG_RETURN_INT64(ntids); + return ntids; } /* @@ -799,14 +795,11 @@ gistgetbitmap(PG_FUNCTION_ARGS) * * Opclasses that implement a fetch function support index-only scans. */ -Datum -gistcanreturn(PG_FUNCTION_ARGS) +bool +gistcanreturn(Relation index, int attno) { - Relation index = (Relation) PG_GETARG_POINTER(0); - int attno = PG_GETARG_INT32(1); - if (OidIsValid(index_getprocid(index, attno, GIST_FETCH_PROC))) - PG_RETURN_BOOL(true); + return true; else - PG_RETURN_BOOL(false); + return false; } -- cgit v1.2.3