176 lines
5.0 KiB
C
176 lines
5.0 KiB
C
/* ACCESS.H -- definitions relating to the access methods. */
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# ifndef PGSIZE
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# define BLKSIZ 512 /* never change */
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# define PGHDR 12 /* size of long mainpg */
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/* + long ovflopg */
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/* + short nxtlino */
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/* + short linetab[0] */
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# define PGSIZE (PGBLKS * BLKSIZ) /* size of page */
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# if PGBLKS == 1
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# define LINETAB(x) -x
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# define AApgsize PGSIZE
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# define AAmaxtup MINTUP
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# else
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# define VPGSIZE /* variable PGSIZE */
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# define LINETAB(x) -(AAltsize + x)
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extern int AApgsize; /* actual page size */
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extern int AAmaxtup; /* actual max. tuple width */
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extern int AAltsize; /* actual linetab size */
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# endif
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/*define PGPTRSIZ 4 ** size of a tid */
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# define MAXTID 253 /* max. tuples per pages */
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# define MODTID 254 /* impossible TID for modify */
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# define SCANTID 255 /* TID for start of scan */
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/* storage structure flags; < 0 means compressed */
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# define M_HEAP 5 /* paged heap */
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# define M_ISAM 11 /* indexed sequential */
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# define M_HASH 21 /* random hash */
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/*define M_BTREE 31 ** BTREES */
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# define M_TRUNC 99 /* internal pseudo-mode: truncated */
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# define NACCBUFS 3 /* number of access method buffers */
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/* error flags */
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# define AMREAD_ERR -1
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# define AMWRITE_ERR -2
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# define AMNOFILE_ERR -3 /* can't open file for a relation */
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/* define AMREL_ERR -4 ** can't open relation relation */
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/* define AMATTR_ERR -5 ** can't open attribute relation */
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# define AMNOATTS_ERR -6 /* attribute missing or xtra in att-rel */
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# define AMCLOSE_ERR -7 /* can't close relation */
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# define AMFIND_ERR -8 /* unidentifiable storage structure in find */
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# define AMINVL_ERR -9 /* invalid TID */
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# define AMOPNVIEW_ERR -10 /* attempt to open a view for rd or wr */
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# define AMSEEK_ERR -11
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# define AMTA_ERR -12
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/* the following is the access methods buffer */
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struct accbuf
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{
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/* this stuff is actually stored in the relation */
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long mainpg; /* next main page (0 - eof) */
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long ovflopg; /* next ovflo page (0 - none) */
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short nxtlino; /* next avail line no for this page */
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char firstup[PGSIZE - PGHDR]; /* tuple space */
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short linetab[1]; /* line table at end of buffer - grows down */
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/* linetab[lineno] is offset into
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** the buffer for that line; linetab[nxtlino]
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** is free space pointer */
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/* this stuff is not stored in the relation */
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long rel_tupid; /* unique relation id */
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long thispage; /* page number of the current page */
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int filedesc; /* file descriptor for this reln */
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struct accbuf *modf; /* use time link list forward pointer */
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struct accbuf *modb; /* back pointer */
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int bufstatus; /* various bits defined below */
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};
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typedef struct accbuf ACCBUF;
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/* The following assignments are status bits for accbuf.bufstatus */
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# define BUF_LOCKED 003 /* page has a page lock on it */
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/*define P_SHR 001 --> shared lock */
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/*define P_EXCL 002 --> exclusive lock */
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# define BUF_DIRECT 004 /* this is a page from isam direct */
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# define BUF_DIRTY 010 /* page has been changed */
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/* access method buffer typed differently for various internal operations */
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struct _acc_buf_
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{
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char acc_buf[PGSIZE];
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};
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typedef struct _acc_buf_ ACC_BUF;
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/* pointers to maintain the buffer */
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extern struct accbuf *AAcc_head; /* head of the LRU list */
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extern struct accbuf *AAcc_tail; /* tail of the LRU list */
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/*
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** ADMIN file struct
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**
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** The ADMIN struct describes the initial part of the ADMIN file
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** which exists in each database. This file is used to initially
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** create the database, to maintain some information about the
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** database, and to access the RELATION and ATTRIBUTE relations
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** on OPENR calls.
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*/
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struct adminhdr
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{
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char adowner[2]; /* user code of data base owner */
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short adflags; /* database flags */
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};
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struct admin
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{
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struct adminhdr adhdr;
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struct descriptor adreld;
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struct descriptor adattd;
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};
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/*
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** AAdmin status bits
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**
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** These bits define the status of the database. They are
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** contained in the adflags field of the admin struct.
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*/
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# define A_DBCONCUR 0000001 /* set database concurrency */
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# define A_QRYMOD 0000002 /* database uses query modification */
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# define A_NEWFMT 0000004 /* database is post-6.3 */
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/* following is buffer space for data from AA_ADMIN file */
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extern struct admin AAdmin;
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/*
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** global counters for the number of BS read and write
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** requests issued by the access methods.
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*/
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extern long AAccuread;
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extern long AAccuwrite;
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/*
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** Global values used by everything
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*/
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extern char *AAcctuple; /* pointer to canonical tuple */
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extern int AAccerror; /* error no for fatal errors */
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# ifdef ESER_PSU
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# define MERGESIZE 6
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# define COREBUFSIZE ( 31 * 1024)
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# else
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# define MERGESIZE 16
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# ifdef MEM_E
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# define COREBUFSIZE (100 * 1024)
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# else
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# define COREBUFSIZE ( 60 * 1024)
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# endif
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# endif
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# define TUP_BUF_SIZ (PGSIZE + MAXTUP + sizeof (long))
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struct tup_hdr
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{
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char *tup_ptr;
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char *tup_end;
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int tup_fd;
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int tup_no;
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int tup_len;
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char tup_buf[TUP_BUF_SIZ];
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};
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extern char Tup_buf[];
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extern char *Tup_ptr;
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extern short Tup_size;
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extern int Tup_fd;
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# endif
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