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Commit 4ba37eed authored by Howard Chu's avatar Howard Chu
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Save free-list in DB

parent 852ac0e3
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libraries/libmdb/mdb.c
View file @ 4ba37eed
......@@ -21,6 +21,7 @@
#include <time.h>
#include <unistd.h>
#include <pthread.h>
#include <endian.h>
#include "mdb.h"
......@@ -272,7 +273,6 @@ struct MDB_env {
MDB_dbx *me_dbxs; /* array */
MDB_db *me_dbs[2];
MDB_oldpages *me_pghead;
MDB_oldpages *me_pgtail;
pthread_key_t me_txkey; /* thread-key for readers */
};
......@@ -309,6 +309,8 @@ static int mdb_add_node(MDB_txn *txn, MDB_dbi dbi, MDB_page *mp,
indx_t indx, MDB_val *key, MDB_val *data,
pgno_t pgno, uint8_t flags);
static void mdb_del_node(MDB_page *mp, indx_t indx);
static int mdb_del0(MDB_txn *txn, MDB_dbi dbi, unsigned int ki,
MDB_pageparent *mpp, MDB_node *leaf);
static int mdb_read_data(MDB_env *env, MDB_node *leaf, MDB_val *data);
static int mdb_rebalance(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *mp);
......@@ -401,9 +403,45 @@ mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num)
{
MDB_dpage *dp;
pgno_t pgno = P_INVALID;
ULONG oldest = txn->mt_txnid - 2;
if (!txn->mt_env->me_pghead && txn->mt_dbs[FREE_DBI].md_root != P_INVALID) {
/* See if there's anything in the free DB */
MDB_pageparent mpp;
MDB_node *leaf;
ULONG *kptr;
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
mdb_search_page(txn, FREE_DBI, NULL, NULL, 0, &mpp);
leaf = NODEPTR(mpp.mp_page, 0);
kptr = (ULONG *)NODEKEY(leaf);
/* It's potentially usable, unless there are still
* older readers outstanding. Grab it.
*/
if (oldest > *kptr) {
MDB_oldpages *mop;
MDB_val data;
pgno_t *idl;
mdb_read_data(txn->mt_env, leaf, &data);
idl = (ULONG *)data.mv_data;
mop = malloc(sizeof(MDB_oldpages) + MDB_IDL_SIZEOF(idl) - sizeof(pgno_t));
mop->mo_next = txn->mt_env->me_pghead;
mop->mo_txnid = *kptr;
txn->mt_env->me_pghead = mop;
memcpy(mop->mo_pages, idl, MDB_IDL_SIZEOF(idl));
/* drop this IDL from the DB */
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
mdb_search_page(txn, FREE_DBI, NULL, NULL, 1, &mpp);
leaf = NODEPTR(mpp.mp_page, 0);
mdb_del0(txn, FREE_DBI, 0, &mpp, leaf);
}
}
if (txn->mt_env->me_pghead) {
ULONG oldest = txn->mt_txnid - 2;
unsigned int i;
for (i=0; i<txn->mt_env->me_txns->mt_numreaders; i++) {
ULONG mr = txn->mt_env->me_txns->mt_readers[i].mr_txnid;
......@@ -432,8 +470,6 @@ mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num)
}
if (MDB_IDL_IS_ZERO(mop->mo_pages)) {
txn->mt_env->me_pghead = mop->mo_next;
if (!txn->mt_env->me_pghead)
txn->mt_env->me_pgtail = NULL;
free(mop);
}
}
......@@ -604,31 +640,12 @@ mdb_txn_abort(MDB_txn *txn)
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
txn->mt_u.reader->mr_txnid = 0;
} else {
/* Discard all dirty pages. Return any re-used pages
* to the free list.
*/
MDB_IDL_ZERO(txn->mt_free_pgs);
/* Discard all dirty pages. */
while (!STAILQ_EMPTY(txn->mt_u.dirty_queue)) {
dp = STAILQ_FIRST(txn->mt_u.dirty_queue);
STAILQ_REMOVE_HEAD(txn->mt_u.dirty_queue, h.md_next);
if (dp->p.mp_pgno <= env->me_meta->mm_last_pg)
mdb_idl_insert(txn->mt_free_pgs, dp->p.mp_pgno);
free(dp);
}
/* put back to head of free list */
if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
MDB_oldpages *mop;
mop = malloc(sizeof(MDB_oldpages) + MDB_IDL_SIZEOF(txn->mt_free_pgs) - sizeof(pgno_t));
mop->mo_next = env->me_pghead;
mop->mo_txnid = txn->mt_oldest - 1;
if (!env->me_pghead) {
env->me_pgtail = mop;
}
env->me_pghead = mop;
memcpy(mop->mo_pages, txn->mt_free_pgs, MDB_IDL_SIZEOF(txn->mt_free_pgs));
}
free(txn->mt_free_pgs);
free(txn->mt_u.dirty_queue);
env->me_txn = NULL;
......@@ -680,6 +697,40 @@ mdb_txn_commit(MDB_txn *txn)
DPRINTF("committing transaction %lu on mdbenv %p, root page %lu",
txn->mt_txnid, (void *) env, txn->mt_dbs[MAIN_DBI].md_root);
/* should only be one record now */
if (env->me_pghead) {
MDB_val key, data;
MDB_oldpages *mop;
mop = env->me_pghead;
key.mv_size = sizeof(pgno_t);
key.mv_data = (char *)&mop->mo_txnid;
data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
data.mv_data = mop->mo_pages;
mdb_put(txn, FREE_DBI, &key, &data, 0);
free(env->me_pghead);
env->me_pghead = NULL;
}
/* save to free list */
if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
MDB_val key, data;
MDB_pageparent mpp;
/* make sure last page of freeDB is touched and on freelist */
key.mv_size = MAXKEYSIZE+1;
key.mv_data = NULL;
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
mdb_search_page(txn, FREE_DBI, &key, NULL, 1, &mpp);
/* write to last page of freeDB */
key.mv_size = sizeof(pgno_t);
key.mv_data = (char *)&txn->mt_txnid;
data.mv_size = MDB_IDL_SIZEOF(txn->mt_free_pgs);
data.mv_data = txn->mt_free_pgs;
mdb_put(txn, FREE_DBI, &key, &data, 0);
}
/* Update DB root pointers. Their pages have already been
* touched so this is all in-place and cannot fail.
*/
......@@ -790,22 +841,6 @@ mdb_txn_commit(MDB_txn *txn)
free(txn->mt_dbs);
}
/* add to tail of free list */
if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
MDB_oldpages *mop;
mop = malloc(sizeof(MDB_oldpages) + MDB_IDL_SIZEOF(txn->mt_free_pgs) - sizeof(pgno_t));
mop->mo_next = NULL;
if (env->me_pghead) {
env->me_pgtail->mo_next = mop;
} else {
env->me_pghead = mop;
}
env->me_pgtail = mop;
memcpy(mop->mo_pages, txn->mt_free_pgs, MDB_IDL_SIZEOF(txn->mt_free_pgs));
mop->mo_txnid = txn->mt_txnid;
}
pthread_mutex_unlock(&env->me_txns->mt_wmutex);
free(txn->mt_free_pgs);
free(txn->mt_u.dirty_queue);
......@@ -879,6 +914,10 @@ mdbenv_init_meta(MDB_env *env, MDB_meta *meta)
meta->mm_psize = psize;
meta->mm_last_pg = 1;
meta->mm_flags = env->me_flags & 0xffff;
#if __BYTE_ORDER == __LITTLE_ENDIAN
/* freeDB keys are pgno_t's, must compare in int order */
meta->mm_flags |= MDB_REVERSEKEY;
#endif
meta->mm_dbs[0].md_root = P_INVALID;
meta->mm_dbs[1].md_root = P_INVALID;
......@@ -2291,6 +2330,32 @@ mdb_rebalance(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *mpp)
}
}
static int
mdb_del0(MDB_txn *txn, MDB_dbi dbi, unsigned int ki, MDB_pageparent *mpp, MDB_node *leaf)
{
int rc;
mdb_del_node(mpp->mp_page, ki);
/* add overflow pages to free list */
if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
int i, ovpages;
pgno_t pg;
memcpy(&pg, NODEDATA(leaf), sizeof(pg));
ovpages = OVPAGES(NODEDSZ(leaf), txn->mt_env->me_psize);
for (i=0; i<ovpages; i++) {
mdb_idl_insert(txn->mt_free_pgs, pg);
pg++;
}
}
txn->mt_dbs[dbi].md_entries--;
rc = mdb_rebalance(txn, dbi, mpp);
if (rc != MDB_SUCCESS)
txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
int
mdb_del(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data)
......@@ -2315,6 +2380,8 @@ mdb_del(MDB_txn *txn, MDB_dbi dbi,
return EINVAL;
}
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
if ((rc = mdb_search_page(txn, dbi, key, NULL, 1, &mpp)) != MDB_SUCCESS)
return rc;
......@@ -2326,25 +2393,7 @@ mdb_del(MDB_txn *txn, MDB_dbi dbi,
if (data && (rc = mdb_read_data(txn->mt_env, leaf, data)) != MDB_SUCCESS)
return rc;
mdb_del_node(mpp.mp_page, ki);
/* add overflow pages to free list */
if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
int i, ovpages;
pgno_t pg;
memcpy(&pg, NODEDATA(leaf), sizeof(pg));
ovpages = OVPAGES(NODEDSZ(leaf), txn->mt_env->me_psize);
for (i=0; i<ovpages; i++) {
mdb_idl_insert(txn->mt_free_pgs, pg);
pg++;
}
}
txn->mt_dbs[dbi].md_entries--;
rc = mdb_rebalance(txn, dbi, &mpp);
if (rc != MDB_SUCCESS)
txn->mt_flags |= MDB_TXN_ERROR;
return rc;
return mdb_del0(txn, dbi, ki, &mpp, leaf);
}
/* Split page <*mpp>, and insert <key,(data|newpgno)> in either left or
......@@ -2534,6 +2583,8 @@ mdb_put(MDB_txn *txn, MDB_dbi dbi,
DPRINTF("==> put key %.*s, size %zu, data size %zu",
(int)key->mv_size, (char *)key->mv_data, key->mv_size, data->mv_size);
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
rc = mdb_search_page(txn, dbi, key, NULL, 1, &mpp);
if (rc == MDB_SUCCESS) {
leaf = mdb_search_node(txn, dbi, mpp.mp_page, key, &exact, &ki);
......
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