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Diffstat (limited to 'src/backend/utils/misc/database.c')
| -rw-r--r-- | src/backend/utils/misc/database.c | 189 |
1 files changed, 0 insertions, 189 deletions
diff --git a/src/backend/utils/misc/database.c b/src/backend/utils/misc/database.c deleted file mode 100644 index 66ea6dbed79..00000000000 --- a/src/backend/utils/misc/database.c +++ /dev/null @@ -1,189 +0,0 @@ -/*------------------------------------------------------------------------- - * - * database.c - * miscellaneous initialization support stuff - * - * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group - * Portions Copyright (c) 1994, Regents of the University of California - * - * - * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/misc/database.c,v 1.63 2004/12/31 22:02:45 pgsql Exp $ - * - *------------------------------------------------------------------------- - */ -#include "postgres.h" - -#include <fcntl.h> -#include <unistd.h> - -#include "access/xact.h" -#include "catalog/catname.h" -#include "catalog/catalog.h" -#include "catalog/pg_database.h" -#include "catalog/pg_tablespace.h" -#include "miscadmin.h" -#include "utils/syscache.h" - - -static bool PhonyHeapTupleSatisfiesNow(HeapTupleHeader tuple); - - -/* -------------------------------- - * GetRawDatabaseInfo() -- Find the OID and tablespace of the database. - * - * We need both the OID and the default tablespace in order to find - * the database's system catalogs. Moreover the database's OID forms - * half of the unique key for the system caches and lock tables, so - * we must have it before we can use any of the cache mechanisms. - * To get around these problems, this code opens and scans the - * pg_database relation by hand. - * - * This code knows way more than it should about the layout of - * tuples on disk, but there seems to be no help for that. - * We're pulling ourselves up by the bootstraps here... - * -------------------------------- - */ -void -GetRawDatabaseInfo(const char *name, Oid *db_id, Oid *db_tablespace) -{ - int dbfd; - int nbytes; - HeapTupleData tup; - Form_pg_database tup_db; - Page pg; - char *dbfname; - RelFileNode rnode; - - /* hard-wired path to pg_database */ - rnode.spcNode = GLOBALTABLESPACE_OID; - rnode.dbNode = 0; - rnode.relNode = RelOid_pg_database; - - dbfname = relpath(rnode); - - if ((dbfd = open(dbfname, O_RDONLY | PG_BINARY, 0)) < 0) - ereport(FATAL, - (errcode_for_file_access(), - errmsg("could not open file \"%s\": %m", dbfname))); - - pfree(dbfname); - - /* - * read and examine every page in pg_database - * - * Raw I/O! Read those tuples the hard way! Yow! - * - * Why don't we use the access methods or move this code someplace else? - * This is really pg_database schema dependent code. Perhaps it - * should go in lib/catalog/pg_database? -cim 10/3/90 - * - * mao replies 4 apr 91: yeah, maybe this should be moved to - * lib/catalog. however, we CANNOT use the access methods since those - * use the buffer cache, which uses the relation cache, which requires - * that the dbid be set, which is what we're trying to do here. - * - */ - pg = (Page) palloc(BLCKSZ); - - while ((nbytes = read(dbfd, pg, BLCKSZ)) == BLCKSZ) - { - OffsetNumber max = PageGetMaxOffsetNumber(pg); - OffsetNumber lineoff; - - /* look at each tuple on the page */ - for (lineoff = FirstOffsetNumber; lineoff <= max; lineoff++) - { - ItemId lpp = PageGetItemId(pg, lineoff); - - /* if it's a freed tuple, ignore it */ - if (!ItemIdIsUsed(lpp)) - continue; - - /* get a pointer to the tuple itself */ - tup.t_datamcxt = NULL; - tup.t_data = (HeapTupleHeader) PageGetItem(pg, lpp); - - /* - * Check to see if tuple is valid (committed). - * - * XXX warning, will robinson: violation of transaction semantics - * happens right here. We cannot really determine if the - * tuple is valid without checking transaction commit status, - * and the only way to do that at init time is to paw over - * pg_clog by hand, too. Instead of checking, we assume that - * the inserting transaction committed, and that any deleting - * transaction did also, unless shown otherwise by on-row - * commit status bits. - * - * All in all, this code is pretty shaky. We will cross-check - * our result in ReverifyMyDatabase() in postinit.c. - * - * NOTE: if a bogus tuple in pg_database prevents connection to a - * valid database, a fix is to connect to another database and - * do "select * from pg_database". That should cause - * committed and dead tuples to be marked with correct states. - * - * XXX wouldn't it be better to let new backends read the - * database info from a flat file, handled the same way we - * handle the password relation? - */ - if (!PhonyHeapTupleSatisfiesNow(tup.t_data)) - continue; - - /* - * Okay, see if this is the one we want. - */ - tup_db = (Form_pg_database) GETSTRUCT(&tup); - - if (strcmp(name, NameStr(tup_db->datname)) == 0) - { - /* Found it; extract the db's OID and tablespace. */ - *db_id = HeapTupleGetOid(&tup); - *db_tablespace = tup_db->dattablespace; - goto done; - } - } - } - - /* failed to find it... */ - *db_id = InvalidOid; - *db_tablespace = InvalidOid; - -done: - close(dbfd); - pfree(pg); -} - -/* - * PhonyHeapTupleSatisfiesNow --- cut-down tuple time qual test - * - * This is a simplified version of HeapTupleSatisfiesNow() that does not - * depend on having transaction commit info available. Any transaction - * that touched the tuple is assumed committed unless later marked invalid. - * (While we could think about more complex rules, this seems appropriate - * for examining pg_database, since both CREATE DATABASE and DROP DATABASE - * are non-roll-back-able.) - */ -static bool -PhonyHeapTupleSatisfiesNow(HeapTupleHeader tuple) -{ - if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED)) - { - if (tuple->t_infomask & HEAP_XMIN_INVALID) - return false; - - if (tuple->t_infomask & HEAP_MOVED_OFF) - return false; - /* else assume committed */ - } - - if (tuple->t_infomask & HEAP_XMAX_INVALID) /* xid invalid or aborted */ - return true; - - /* assume xmax transaction committed */ - if (tuple->t_infomask & HEAP_MARKED_FOR_UPDATE) - return true; - - return false; -} |