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/gistvalidate.c | 133 +++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 src/backend/access/gist/gistvalidate.c (limited to 'src/backend/access/gist/gistvalidate.c') diff --git a/src/backend/access/gist/gistvalidate.c b/src/backend/access/gist/gistvalidate.c new file mode 100644 index 00000000000..86b5aeaec5c --- /dev/null +++ b/src/backend/access/gist/gistvalidate.c @@ -0,0 +1,133 @@ +/*------------------------------------------------------------------------- + * + * gistvalidate.c + * Opclass validator for GiST. + * + * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/backend/access/gist/gistvalidate.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include "access/gist_private.h" +#include "access/htup_details.h" +#include "catalog/pg_amop.h" +#include "catalog/pg_amproc.h" +#include "catalog/pg_opclass.h" +#include "utils/catcache.h" +#include "utils/syscache.h" + + +/* + * Validator for a GiST opclass. + */ +bool +gistvalidate(Oid opclassoid) +{ + HeapTuple classtup; + Form_pg_opclass classform; + Oid opfamilyoid; + Oid opcintype; + int numclassops; + int32 classfuncbits; + CatCList *proclist, + *oprlist; + int i; + + /* Fetch opclass information */ + classtup = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclassoid)); + if (!HeapTupleIsValid(classtup)) + elog(ERROR, "cache lookup failed for operator class %u", opclassoid); + classform = (Form_pg_opclass) GETSTRUCT(classtup); + + opfamilyoid = classform->opcfamily; + opcintype = classform->opcintype; + + ReleaseSysCache(classtup); + + /* Fetch all operators and support functions of the opfamily */ + oprlist = SearchSysCacheList1(AMOPSTRATEGY, ObjectIdGetDatum(opfamilyoid)); + proclist = SearchSysCacheList1(AMPROCNUM, ObjectIdGetDatum(opfamilyoid)); + + /* We'll track the ops and functions belonging to the named opclass */ + numclassops = 0; + classfuncbits = 0; + + /* Check support functions */ + for (i = 0; i < proclist->n_members; i++) + { + HeapTuple proctup = &proclist->members[i]->tuple; + Form_pg_amproc procform = (Form_pg_amproc) GETSTRUCT(proctup); + + /* Check that only allowed procedure numbers exist */ + if (procform->amprocnum < 1 || + procform->amprocnum > GISTNProcs) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("gist opfamily %u contains invalid support number %d for procedure %u", + opfamilyoid, + procform->amprocnum, procform->amproc))); + + /* Remember functions that are specifically for the named opclass */ + if (procform->amproclefttype == opcintype && + procform->amprocrighttype == opcintype) + classfuncbits |= (1 << procform->amprocnum); + } + + /* Check operators */ + for (i = 0; i < oprlist->n_members; i++) + { + HeapTuple oprtup = &oprlist->members[i]->tuple; + Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup); + + /* TODO: Check that only allowed strategy numbers exist */ + if (oprform->amopstrategy < 1) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("gist opfamily %u contains invalid strategy number %d for operator %u", + opfamilyoid, + oprform->amopstrategy, oprform->amopopr))); + + /* GiST supports ORDER BY operators, but must have distance proc */ + if (oprform->amoppurpose != AMOP_SEARCH && + oprform->amoplefttype == opcintype && + oprform->amoprighttype == opcintype && + (classfuncbits & (1 << GIST_DISTANCE_PROC)) == 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("gist opfamily %u contains unsupported ORDER BY specification for operator %u", + opfamilyoid, oprform->amopopr))); + + /* Count operators that are specifically for the named opclass */ + /* XXX we consider only lefttype here */ + if (oprform->amoplefttype == opcintype) + numclassops++; + } + + /* Check that the named opclass is complete */ + if (numclassops == 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("gist opclass %u is missing operator(s)", + opclassoid))); + for (i = 1; i <= GISTNProcs; i++) + { + if ((classfuncbits & (1 << i)) != 0) + continue; /* got it */ + if (i == GIST_DISTANCE_PROC || i == GIST_FETCH_PROC) + continue; /* optional methods */ + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("gist opclass %u is missing required support function %d", + opclassoid, i))); + } + + ReleaseCatCacheList(proclist); + ReleaseCatCacheList(oprlist); + + return true; +} -- cgit v1.2.3