hash_stat.c
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上传日期:2022-05-23
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文件大小:9k
- /*-
- * See the file LICENSE for redistribution information.
- *
- * Copyright (c) 1996-2002
- * Sleepycat Software. All rights reserved.
- */
- #include "db_config.h"
- #ifndef lint
- static const char revid[] = "$Id: hash_stat.c,v 11.48 2002/08/06 06:11:28 bostic Exp $";
- #endif /* not lint */
- #ifndef NO_SYSTEM_INCLUDES
- #include <sys/types.h>
- #include <string.h>
- #endif
- #include "db_int.h"
- #include "dbinc/db_page.h"
- #include "dbinc/btree.h"
- #include "dbinc/hash.h"
- static int __ham_stat_callback __P((DB *, PAGE *, void *, int *));
- /*
- * __ham_stat --
- * Gather/print the hash statistics
- *
- * PUBLIC: int __ham_stat __P((DB *, void *, u_int32_t));
- */
- int
- __ham_stat(dbp, spp, flags)
- DB *dbp;
- void *spp;
- u_int32_t flags;
- {
- DBC *dbc;
- DB_ENV *dbenv;
- DB_HASH_STAT *sp;
- DB_MPOOLFILE *mpf;
- HASH_CURSOR *hcp;
- PAGE *h;
- db_pgno_t pgno;
- int ret;
- dbenv = dbp->dbenv;
- PANIC_CHECK(dbenv);
- DB_ILLEGAL_BEFORE_OPEN(dbp, "DB->stat");
- mpf = dbp->mpf;
- sp = NULL;
- /* Check for invalid flags. */
- if ((ret = __db_statchk(dbp, flags)) != 0)
- return (ret);
- if ((ret = dbp->cursor(dbp, NULL, &dbc, 0)) != 0)
- return (ret);
- hcp = (HASH_CURSOR *)dbc->internal;
- if ((ret = __ham_get_meta(dbc)) != 0)
- goto err;
- /* Allocate and clear the structure. */
- if ((ret = __os_umalloc(dbenv, sizeof(*sp), &sp)) != 0)
- goto err;
- memset(sp, 0, sizeof(*sp));
- /* Copy the fields that we have. */
- sp->hash_nkeys = hcp->hdr->dbmeta.key_count;
- sp->hash_ndata = hcp->hdr->dbmeta.record_count;
- sp->hash_pagesize = dbp->pgsize;
- sp->hash_buckets = hcp->hdr->max_bucket + 1;
- sp->hash_magic = hcp->hdr->dbmeta.magic;
- sp->hash_version = hcp->hdr->dbmeta.version;
- sp->hash_metaflags = hcp->hdr->dbmeta.flags;
- sp->hash_ffactor = hcp->hdr->ffactor;
- if (flags == DB_FAST_STAT || flags == DB_CACHED_COUNTS)
- goto done;
- /* Walk the free list, counting pages. */
- for (sp->hash_free = 0, pgno = hcp->hdr->dbmeta.free;
- pgno != PGNO_INVALID;) {
- ++sp->hash_free;
- if ((ret = mpf->get(mpf, &pgno, 0, &h)) != 0)
- goto err;
- pgno = h->next_pgno;
- (void)mpf->put(mpf, h, 0);
- }
- /* Now traverse the rest of the table. */
- sp->hash_nkeys = 0;
- sp->hash_ndata = 0;
- if ((ret = __ham_traverse(dbc,
- DB_LOCK_READ, __ham_stat_callback, sp, 0)) != 0)
- goto err;
- if (!F_ISSET(dbp, DB_AM_RDONLY)) {
- if ((ret = __ham_dirty_meta(dbc)) != 0)
- goto err;
- hcp->hdr->dbmeta.key_count = sp->hash_nkeys;
- hcp->hdr->dbmeta.record_count = sp->hash_ndata;
- }
- done:
- if ((ret = __ham_release_meta(dbc)) != 0)
- goto err;
- if ((ret = dbc->c_close(dbc)) != 0)
- goto err;
- *(DB_HASH_STAT **)spp = sp;
- return (0);
- err: if (sp != NULL)
- __os_ufree(dbenv, sp);
- if (hcp->hdr != NULL)
- (void)__ham_release_meta(dbc);
- (void)dbc->c_close(dbc);
- return (ret);
- }
- /*
- * __ham_traverse
- * Traverse an entire hash table. We use the callback so that we
- * can use this both for stat collection and for deallocation.
- *
- * PUBLIC: int __ham_traverse __P((DBC *, db_lockmode_t,
- * PUBLIC: int (*)(DB *, PAGE *, void *, int *), void *, int));
- */
- int
- __ham_traverse(dbc, mode, callback, cookie, look_past_max)
- DBC *dbc;
- db_lockmode_t mode;
- int (*callback) __P((DB *, PAGE *, void *, int *));
- void *cookie;
- int look_past_max;
- {
- DB *dbp;
- DBC *opd;
- DB_MPOOLFILE *mpf;
- HASH_CURSOR *hcp;
- HKEYDATA *hk;
- db_pgno_t pgno, opgno;
- int did_put, i, ret, t_ret;
- u_int32_t bucket, spares_entry;
- dbp = dbc->dbp;
- opd = NULL;
- mpf = dbp->mpf;
- hcp = (HASH_CURSOR *)dbc->internal;
- ret = 0;
- /*
- * In a perfect world, we could simply read each page in the file
- * and look at its page type to tally the information necessary.
- * Unfortunately, the bucket locking that hash tables do to make
- * locking easy, makes this a pain in the butt. We have to traverse
- * duplicate, overflow and big pages from the bucket so that we
- * don't access anything that isn't properly locked.
- *
- */
- for (bucket = 0;; bucket++) {
- /*
- * We put the loop exit condition check here, because
- * it made for a really vile extended ?: that made SCO's
- * compiler drop core.
- *
- * If look_past_max is not set, we can stop at max_bucket;
- * if it is set, we need to include pages that are part of
- * the current doubling but beyond the highest bucket we've
- * split into, as well as pages from a "future" doubling
- * that may have been created within an aborted
- * transaction. To do this, keep looping (and incrementing
- * bucket) until the corresponding spares array entries
- * cease to be defined.
- */
- if (look_past_max) {
- spares_entry = __db_log2(bucket + 1);
- if (spares_entry >= NCACHED ||
- hcp->hdr->spares[spares_entry] == 0)
- break;
- } else {
- if (bucket > hcp->hdr->max_bucket)
- break;
- }
- hcp->bucket = bucket;
- hcp->pgno = pgno = BUCKET_TO_PAGE(hcp, bucket);
- for (ret = __ham_get_cpage(dbc, mode); ret == 0;
- ret = __ham_next_cpage(dbc, pgno, 0)) {
- /*
- * If we are cleaning up pages past the max_bucket,
- * then they may be on the free list and have their
- * next pointers set, but the should be ignored. In
- * fact, we really ought to just skip anybody who is
- * not a valid page.
- */
- if (TYPE(hcp->page) == P_INVALID)
- break;
- pgno = NEXT_PGNO(hcp->page);
- /*
- * Go through each item on the page checking for
- * duplicates (in which case we have to count the
- * duplicate pages) or big key/data items (in which
- * case we have to count those pages).
- */
- for (i = 0; i < NUM_ENT(hcp->page); i++) {
- hk = (HKEYDATA *)P_ENTRY(dbp, hcp->page, i);
- switch (HPAGE_PTYPE(hk)) {
- case H_OFFDUP:
- memcpy(&opgno, HOFFDUP_PGNO(hk),
- sizeof(db_pgno_t));
- if ((ret = __db_c_newopd(dbc,
- opgno, NULL, &opd)) != 0)
- return (ret);
- if ((ret = __bam_traverse(opd,
- DB_LOCK_READ, opgno,
- callback, cookie))
- != 0)
- goto err;
- if ((ret = opd->c_close(opd)) != 0)
- return (ret);
- opd = NULL;
- break;
- case H_OFFPAGE:
- /*
- * We are about to get a big page
- * which will use the same spot that
- * the current page uses, so we need
- * to restore the current page before
- * looking at it again.
- */
- memcpy(&opgno, HOFFPAGE_PGNO(hk),
- sizeof(db_pgno_t));
- if ((ret = __db_traverse_big(dbp,
- opgno, callback, cookie)) != 0)
- goto err;
- break;
- case H_KEYDATA:
- break;
- }
- }
- /* Call the callback on main pages. */
- if ((ret = callback(dbp,
- hcp->page, cookie, &did_put)) != 0)
- goto err;
- if (did_put)
- hcp->page = NULL;
- if (pgno == PGNO_INVALID)
- break;
- }
- if (ret != 0)
- goto err;
- if (STD_LOCKING(dbc))
- (void)dbp->dbenv->lock_put(dbp->dbenv, &hcp->lock);
- if (hcp->page != NULL) {
- if ((ret = mpf->put(mpf, hcp->page, 0)) != 0)
- return (ret);
- hcp->page = NULL;
- }
- }
- err: if (opd != NULL &&
- (t_ret = opd->c_close(opd)) != 0 && ret == 0)
- ret = t_ret;
- return (ret);
- }
- static int
- __ham_stat_callback(dbp, pagep, cookie, putp)
- DB *dbp;
- PAGE *pagep;
- void *cookie;
- int *putp;
- {
- DB_HASH_STAT *sp;
- DB_BTREE_STAT bstat;
- db_indx_t indx, len, off, tlen, top;
- u_int8_t *hk;
- int ret;
- *putp = 0;
- sp = cookie;
- switch (pagep->type) {
- case P_INVALID:
- /*
- * Hash pages may be wholly zeroed; this is not a bug.
- * Obviously such pages have no data, so we can just proceed.
- */
- break;
- case P_HASH:
- /*
- * We count the buckets and the overflow pages
- * separately and tally their bytes separately
- * as well. We need to figure out if this page
- * is a bucket.
- */
- if (PREV_PGNO(pagep) == PGNO_INVALID)
- sp->hash_bfree += P_FREESPACE(dbp, pagep);
- else {
- sp->hash_overflows++;
- sp->hash_ovfl_free += P_FREESPACE(dbp, pagep);
- }
- top = NUM_ENT(pagep);
- /* Correct for on-page duplicates and deleted items. */
- for (indx = 0; indx < top; indx += P_INDX) {
- switch (*H_PAIRDATA(dbp, pagep, indx)) {
- case H_OFFDUP:
- case H_OFFPAGE:
- break;
- case H_KEYDATA:
- sp->hash_ndata++;
- break;
- case H_DUPLICATE:
- tlen = LEN_HDATA(dbp, pagep, 0, indx);
- hk = H_PAIRDATA(dbp, pagep, indx);
- for (off = 0; off < tlen;
- off += len + 2 * sizeof (db_indx_t)) {
- sp->hash_ndata++;
- memcpy(&len,
- HKEYDATA_DATA(hk)
- + off, sizeof(db_indx_t));
- }
- }
- }
- sp->hash_nkeys += H_NUMPAIRS(pagep);
- break;
- case P_IBTREE:
- case P_IRECNO:
- case P_LBTREE:
- case P_LRECNO:
- case P_LDUP:
- /*
- * These are all btree pages; get a correct
- * cookie and call them. Then add appropriate
- * fields into our stat structure.
- */
- memset(&bstat, 0, sizeof(bstat));
- bstat.bt_dup_pgfree = 0;
- bstat.bt_int_pgfree = 0;
- bstat.bt_leaf_pgfree = 0;
- bstat.bt_ndata = 0;
- if ((ret = __bam_stat_callback(dbp, pagep, &bstat, putp)) != 0)
- return (ret);
- sp->hash_dup++;
- sp->hash_dup_free += bstat.bt_leaf_pgfree +
- bstat.bt_dup_pgfree + bstat.bt_int_pgfree;
- sp->hash_ndata += bstat.bt_ndata;
- break;
- case P_OVERFLOW:
- sp->hash_bigpages++;
- sp->hash_big_bfree += P_OVFLSPACE(dbp, dbp->pgsize, pagep);
- break;
- default:
- return (__db_pgfmt(dbp->dbenv, pagep->pgno));
- }
- return (0);
- }