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Support alternate database locations.

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This commit is contained in:
Thomas G. Lockhart
1997-11-07 06:38:51 +00:00
parent d98f2f9985
commit 7d1f2f8a27
8 changed files with 273 additions and 254 deletions
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348
src/backend/utils/init/postinit.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.14 1997/09/08 02:31:58 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.15 1997/11/07 06:38:46 thomas Exp $
*
* NOTES
* InitPostgres() is the function called from PostgresMain
@ -50,7 +50,7 @@
#include "access/transam.h" /* XXX dependency problem */
#include "utils/tqual.h"
#include "utils/syscache.h"
#include "storage/bufpage.h" /* for page layout, for InitMyDatabaseId() */
#include "storage/bufpage.h" /* for page layout, for InitMyDatabaseInfo() */
#include "storage/sinval.h"
#include "storage/sinvaladt.h"
#include "storage/lmgr.h"
@ -70,11 +70,15 @@
#include "port-protos.h"
#include "libpq/libpq-be.h"
static void VerifySystemDatabase(void);
static void VerifyMyDatabase(void);
static void InitCommunication(void);
static void InitMyDatabaseId(void);
static void InitMyDatabaseInfo(char *name);
static void InitStdio(void);
static void InitUserid(void);
extern char *ExpandDatabasePath(char *name);
extern void GetRawDatabaseInfo(char *name, Oid *owner, Oid *db_id, char *path);
static IPCKey PostgresIpcKey;
@ -84,7 +88,7 @@ static IPCKey PostgresIpcKey;
*/
/* --------------------------------
* InitMyDatabaseId() -- Find and record the OID of the database we are
* InitMyDatabaseInfo() -- Find and record the OID of the database we are
* to open.
*
* The database's oid forms half of the unique key for the system
@ -98,133 +102,38 @@ static IPCKey PostgresIpcKey;
* about the internal format of tuples on disk and the length of
* the datname attribute. It knows the location of the pg_database
* file.
* Actually, the code looks as though it is using the pg_database
* tuple definition to locate the database name, so the above statement
* seems to be no longer correct. - thomas 1997-11-01
*
* This code is called from InitDatabase(), after we chdir() to the
* database directory but before we open any relations.
* This code is called from InitPostgres(), before we chdir() to the
* local database directory and before we open any relations.
* Used to be called after the chdir(), but we now want to confirm
* the location of the target database using pg_database info.
* - thomas 1997-11-01
* --------------------------------
*/
static void
InitMyDatabaseId()
InitMyDatabaseInfo(char *name)
{
int dbfd;
int fileflags;
int nbytes;
int max,
i;
HeapTuple tup;
Page pg;
PageHeader ph;
char *dbfname;
Form_pg_database tup_db;
Oid owner;
char *path,
myPath[MAXPGPATH+1];
/*
* At bootstrap time, we don't need to check the oid of the database
* in use, since we're not using shared memory. This is lucky, since
* the database may not be in the tables yet.
*/
if (IsBootstrapProcessingMode())
{
LockDisable(true);
return;
}
dbfname = (char *) palloc(strlen(DataDir) + strlen("pg_database") + 2);
sprintf(dbfname, "%s%cpg_database", DataDir, SEP_CHAR);
fileflags = O_RDONLY;
if ((dbfd = open(dbfname, O_RDONLY, 0)) < 0)
elog(FATAL, "Cannot open %s", 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);
ph = (PageHeader) pg;
while ((nbytes = read(dbfd, pg, BLCKSZ)) == BLCKSZ)
{
max = PageGetMaxOffsetNumber(pg);
/* look at each tuple on the page */
for (i = 0; i <= max; i++)
{
int offset;
/* if it's a freed tuple, ignore it */
if (!(ph->pd_linp[i].lp_flags & LP_USED))
continue;
/* get a pointer to the tuple itself */
offset = (int) ph->pd_linp[i].lp_off;
tup = (HeapTuple) (((char *) pg) + offset);
/*
* if the tuple has been deleted (the database was destroyed),
* skip this tuple. XXX warning, will robinson: violation of
* transaction semantics happens right here. we should check
* to be sure that the xact that deleted this tuple actually
* committed. only way to do this at init time is to paw over
* the log relation by hand, too. let's be optimistic.
*
* XXX This is an evil type cast. tup->t_xmax is char[5] while
* TransactionId is struct * { char data[5] }. It works but
* if data is ever moved and no longer the first field this
* will be broken!! -mer 11 Nov 1991.
*/
if (TransactionIdIsValid((TransactionId) tup->t_xmax))
continue;
/*
* Okay, see if this is the one we want. XXX 1 july 91: mao
* and mer discover that tuples now squash t_bits. Why is
* this?
*
* 24 july 92: mer realizes that the t_bits field is only used
* in the event of null values. If no fields are null we
* reduce the header size by doing the squash. t_hoff tells
* you exactly how big the header actually is. use the PC
* means of getting at sys cat attrs.
*/
tup_db = (Form_pg_database) GETSTRUCT(tup);
if (strncmp(GetDatabaseName(),
&(tup_db->datname.data[0]),
16) == 0)
{
MyDatabaseId = tup->t_oid;
goto done;
}
}
}
done:
close(dbfd);
pfree(pg);
SetDatabaseName(name);
GetRawDatabaseInfo(name, &owner, &MyDatabaseId, myPath);
if (!OidIsValid(MyDatabaseId))
elog(FATAL,
"Database %s does not exist in %s",
GetDatabaseName(),
DatabaseRelationName);
}
path = ExpandDatabasePath(myPath);
SetDatabasePath(path);
return;
} /* InitMyDatabaseInfo() */
/*
@ -237,21 +146,21 @@ done:
*
* Arguments:
* Path and name are invalid if it invalid as a string.
* Path is "badly formated" if it is not a string containing a path
* Path is "badly formatted" if it is not a string containing a path
* to a writable directory.
* Name is "badly formated" if it contains more than 16 characters or if
* Name is "badly formatted" if it contains more than 16 characters or if
* it is a bad file name (e.g., it contains a '/' or an 8-bit character).
*
* Exceptions:
* BadState if called more than once.
* BadArg if both path and name are "badly formated" or invalid.
* BadArg if both path and name are "badly formatted" or invalid.
* BadArg if path and name are both "inconsistent" and valid.
*
* This routine is inappropriate in bootstrap mode, since the directories
* and version files need not exist yet if we're in bootstrap mode.
*/
static void
DoChdirAndInitDatabaseNameAndPath(char *name)
VerifySystemDatabase()
{
char *reason;
@ -261,85 +170,88 @@ DoChdirAndInitDatabaseNameAndPath(char *name)
if ((fd = open(DataDir, O_RDONLY, 0)) == -1)
sprintf(errormsg, "Database system does not exist. "
"PGDATA directory '%s' not found. Normally, you "
"PGDATA directory '%s' not found.\n\tNormally, you "
"create a database system by running initdb.",
DataDir);
else
{
char myPath[MAXPGPATH]; /* DatabasePath points here! */
close(fd);
if (strlen(DataDir) + strlen(name) + 10 > sizeof(myPath))
sprintf(errormsg, "Internal error in postinit.c: database "
"pathname exceeds maximum allowable length.");
else
{
sprintf(myPath, "%s/base/%s", DataDir, name);
if ((fd = open(myPath, O_RDONLY, 0)) == -1)
sprintf(errormsg,
"Database '%s' does not exist. "
"(We know this because the directory '%s' "
"does not exist). You can create a database "
"with the SQL command CREATE DATABASE. To see "
"what databases exist, look at the subdirectories "
"of '%s/base/'.",
name, myPath, DataDir);
else
{
close(fd);
ValidatePgVersion(DataDir, &reason);
if (reason != NULL)
sprintf(errormsg,
"InitPostgres could not validate that the database "
"system version is compatible with this level of "
"Postgres. You may need to run initdb to create "
"a new database system. %s",
reason);
else
{
ValidatePgVersion(myPath, &reason);
if (reason != NULL)
sprintf(errormsg,
"InitPostgres could not validate that the "
"database version is compatible with this level "
"of Postgres, even though the database system "
"as a whole appears to be at a compatible level. "
"You may need to recreate the database with SQL "
"commands DROP DATABASE and CREATE DATABASE. "
"%s",
reason);
else
{
/*
* The directories and PG_VERSION files are in
* order.
*/
int rc; /* return code from some function
* we call */
SetDatabasePath(myPath);
SetDatabaseName(name);
rc = chdir(myPath);
if (rc < 0)
sprintf(errormsg,
"InitPostgres unable to change "
"current directory to '%s', errno = %s (%d).",
myPath, strerror(errno), errno);
else
errormsg[0] = '\0';
}
}
}
}
ValidatePgVersion(DataDir, &reason);
if (reason != NULL)
sprintf(errormsg,
"InitPostgres could not validate that the database"
" system version is compatible with this level of"
" Postgres.\n\tYou may need to run initdb to create"
" a new database system.\n\t%s", reason);
}
if (errormsg[0] != '\0')
elog(FATAL, errormsg);
/* Above does not return */
}
} /* VerifySystemDatabase() */
static void
VerifyMyDatabase()
{
char *name;
char *myPath;
/* Failure reason returned by some function. NULL if no failure */
char *reason;
int fd;
char errormsg[1000];
name = GetDatabaseName();
myPath = GetDatabasePath();
if ((fd = open(myPath, O_RDONLY, 0)) == -1)
sprintf(errormsg,
"Database '%s' does not exist."
"\n\tWe know this because the directory '%s' does not exist."
"\n\tYou can create a database with the SQL command"
" CREATE DATABASE.\n\tTo see what databases exist,"
" look at the subdirectories of '%s/base/'.",
name, myPath, DataDir);
else
{
close(fd);
ValidatePgVersion(myPath, &reason);
if (reason != NULL)
sprintf(errormsg,
"InitPostgres could not validate that the database"
" version is compatible with this level of Postgres"
"\n\teven though the database system as a whole"
" appears to be at a compatible level."
"\n\tYou may need to recreate the database with SQL"
" commands DROP DATABASE and CREATE DATABASE."
"\n\t%s", reason);
else
{
/*
* The directories and PG_VERSION files are in order.
*/
int rc; /* return code from some function we call */
#ifdef FILEDEBUG
printf("Try changing directory for database %s to %s\n", name, myPath);
#endif
rc = chdir(myPath);
if (rc < 0)
sprintf(errormsg,
"InitPostgres unable to change "
"current directory to '%s', errno = %s (%d).",
myPath, strerror(errno), errno);
else
errormsg[0] = '\0';
}
}
if (errormsg[0] != '\0')
elog(FATAL, errormsg);
/* Above does not return */
} /* VerifyMyDatabase() */
/* --------------------------------
* InitUserid
@ -569,34 +481,43 @@ InitPostgres(char *name) /* database name */
if (!TransactionFlushEnabled())
on_exitpg(FlushBufferPool, (caddr_t) NULL);
if (bootstrap)
{
SetDatabasePath(".");
SetDatabaseName(name);
}
else
{
DoChdirAndInitDatabaseNameAndPath(name);
}
/*
* ******************************** code after this point assumes we
* are in the proper directory! ********************************
*
*/
/* ----------------
* initialize the database id used for system caches and lock tables
* ----------------
*/
InitMyDatabaseId();
if (bootstrap)
{
SetDatabasePath(ExpandDatabasePath(name));
SetDatabaseName(name);
LockDisable(true);
}
else
{
VerifySystemDatabase();
InitMyDatabaseInfo(name);
VerifyMyDatabase();
}
/*
* ********************************
* code after this point assumes we are in the proper directory!
*
* So, how do we implement alternate locations for databases?
* There are two possible locations for tables and we need to look
* in DataDir/pg_database to find the true location of an
* individual database. We can brute-force it as done in
* InitMyDatabaseInfo(), or we can be patient and wait until we
* open pg_database gracefully. Will try that, but may not work...
* - thomas 1997-11-01
* ********************************
*/
/* Does not touch files (?) - thomas 1997-11-01 */
smgrinit();
/* ----------------
* initialize the transaction system and the relation descriptor
* cache. Note we have to make certain the lock manager is off while
* we do this.
* initialize the transaction system and the relation descriptor cache.
* Note we have to make certain the lock manager is off while we do this.
* ----------------
*/
AmiTransactionOverride(IsBootstrapProcessingMode());
@ -610,8 +531,7 @@ InitPostgres(char *name) /* database name */
* after initdb is done. -mer 15 June 1992
*/
RelationInitialize(); /* pre-allocated reldescs created here */
InitializeTransactionSystem(); /* pg_log,etc init/crash recovery
* here */
InitializeTransactionSystem(); /* pg_log,etc init/crash recovery here */
LockDisable(false);
@ -641,6 +561,7 @@ InitPostgres(char *name) /* database name */
/* ----------------
* initialize the access methods.
* Does not touch files (?) - thomas 1997-11-01
* ----------------
*/
initam();
@ -650,6 +571,9 @@ InitPostgres(char *name) /* database name */
* ----------------
*/
zerocaches();
/* Does not touch files since all routines are builtins (?)
* - thomas 1997-11-01
*/
InitCatalogCache();
/* ----------------