/*
* __curfile_remove --
* WT_CURSOR->remove method for the btree cursor type.
*/
static int
__curfile_remove(WT_CURSOR *cursor)
{
WT_CURSOR_BTREE *cbt;
WT_DECL_RET;
WT_SESSION_IMPL *session;
cbt = (WT_CURSOR_BTREE *)cursor;
CURSOR_UPDATE_API_CALL(cursor, session, remove, cbt->btree);
WT_CURSOR_NEEDKEY(cursor);
WT_CURSOR_NOVALUE(cursor);
WT_BTREE_CURSOR_SAVE_AND_RESTORE(cursor, __wt_btcur_remove(cbt), ret);
/*
* After a successful remove, copy the key: the value is not available.
*/
if (ret == 0) {
if (F_ISSET(cursor, WT_CURSTD_KEY_INT) &&
!WT_DATA_IN_ITEM(&(cursor)->key)) {
WT_ERR(__wt_buf_set(session, &cursor->key,
cursor->key.data, cursor->key.size));
F_CLR(cursor, WT_CURSTD_KEY_INT);
F_SET(cursor, WT_CURSTD_KEY_EXT);
}
F_CLR(cursor, WT_CURSTD_VALUE_SET);
}
err: CURSOR_UPDATE_API_END(session, ret);
return (ret);
}
/*
* __async_set_key --
* WT_ASYNC_OP->set_key implementation for op handles.
*/
static void
__async_set_key(WT_ASYNC_OP *asyncop, ...)
{
WT_CURSOR *c;
va_list ap;
c = &asyncop->c;
va_start(ap, asyncop);
__wt_cursor_set_keyv(c, c->flags, ap);
if (!WT_DATA_IN_ITEM(&c->key) && !WT_CURSOR_RECNO(c))
c->saved_err = __wt_buf_set(
O2S((WT_ASYNC_OP_IMPL *)asyncop),
&c->key, c->key.data, c->key.size);
va_end(ap);
}
/*
* __async_set_value --
* WT_ASYNC_OP->set_value implementation for op handles.
*/
static void
__async_set_value(WT_ASYNC_OP *asyncop, ...)
{
WT_CURSOR *c;
va_list ap;
c = &asyncop->c;
va_start(ap, asyncop);
__wt_cursor_set_valuev(c, ap);
/* Copy the data, if it is pointing at data elsewhere. */
if (!WT_DATA_IN_ITEM(&c->value))
c->saved_err = __wt_buf_set(
O2S((WT_ASYNC_OP_IMPL *)asyncop),
&c->value, c->value.data, c->value.size);
va_end(ap);
}
/*尝试重分配ITEM中的mem*/
int __wt_buf_grow_worker(WT_SESSION_IMPL *session, WT_ITEM *buf, size_t size)
{
size_t offset;
int copy_data; /*需要拷贝数据的长度*/
/*判断buf->data是否在buf->mem上，如果在，不用做数据拷贝*/
if(WT_DATA_IN_ITEM(buf)){
offset =WT_PTRDIFF(buf->data, buf->mem);
copy_data = 0;
}
else{
offset = 0;
copy_data = buf->size ? 1 : 0;
}
/*进行内存重分配*/
if(size > buf->memsize){
if (F_ISSET(buf, WT_ITEM_ALIGNED))
WT_RET(__wt_realloc_aligned(session, &buf->memsize, size, &buf->mem));
else
WT_RET(__wt_realloc(session, &buf->memsize, size, &buf->mem));
}
if(buf->data == NULL){
buf->data = buf->mem;
buf->size = 0;
}
else{
if (copy_data) /*进行数据拷贝*/
memcpy(buf->mem, buf->data, buf->size);
buf->data = (uint8_t *)buf->mem + offset;
}
return 0;
}
/*
* __page_read --
* Read a page from the file.
*/
static int
__page_read(WT_SESSION_IMPL *session, WT_REF *ref)
{
const WT_PAGE_HEADER *dsk;
WT_BTREE *btree;
WT_DECL_RET;
WT_ITEM tmp;
WT_PAGE *page;
size_t addr_size;
uint32_t previous_state;
const uint8_t *addr;
btree = S2BT(session);
page = NULL;
/*
* Don't pass an allocated buffer to the underlying block read function,
* force allocation of new memory of the appropriate size.
*/
WT_CLEAR(tmp);
/*
* Attempt to set the state to WT_REF_READING for normal reads, or
* WT_REF_LOCKED, for deleted pages. If successful, we've won the
* race, read the page.
*/
if (__wt_atomic_casv32(&ref->state, WT_REF_DISK, WT_REF_READING))
previous_state = WT_REF_DISK;
else if (__wt_atomic_casv32(&ref->state, WT_REF_DELETED, WT_REF_LOCKED))
previous_state = WT_REF_DELETED;
else
return (0);
/*
* Get the address: if there is no address, the page was deleted, but a
* subsequent search or insert is forcing re-creation of the name space.
*/
WT_ERR(__wt_ref_info(session, ref, &addr, &addr_size, NULL));
if (addr == NULL) {
WT_ASSERT(session, previous_state == WT_REF_DELETED);
WT_ERR(__wt_btree_new_leaf_page(session, &page));
ref->page = page;
goto done;
}
/*
* There's an address, read or map the backing disk page and build an
* in-memory version of the page.
*/
WT_ERR(__wt_bt_read(session, &tmp, addr, addr_size));
WT_ERR(__wt_page_inmem(session, ref, tmp.data, tmp.memsize,
WT_DATA_IN_ITEM(&tmp) ?
WT_PAGE_DISK_ALLOC : WT_PAGE_DISK_MAPPED, &page));
/*
* Clear the local reference to an allocated copy of the disk image on
* return; the page steals it, errors in this code should not free it.
*/
tmp.mem = NULL;
/*
* If reading for a checkpoint, there's no additional work to do, the
* page on disk is correct as written.
*/
if (session->dhandle->checkpoint != NULL)
goto done;
/* If the page was deleted, instantiate that information. */
if (previous_state == WT_REF_DELETED)
WT_ERR(__wt_delete_page_instantiate(session, ref));
/*
* Instantiate updates from the database's lookaside table. The page
* flag was set when the page was written, potentially a long time ago.
* We only care if the lookaside table is currently active, check that
* before doing any work.
*/
dsk = tmp.data;
if (F_ISSET(dsk, WT_PAGE_LAS_UPDATE) && __wt_las_is_written(session)) {
WT_STAT_FAST_CONN_INCR(session, cache_read_lookaside);
WT_STAT_FAST_DATA_INCR(session, cache_read_lookaside);
WT_ERR(__las_page_instantiate(
session, ref, btree->id, addr, addr_size));
}
done: WT_PUBLISH(ref->state, WT_REF_MEM);
return (0);
err: /*
* If the function building an in-memory version of the page failed,
* it discarded the page, but not the disk image. Discard the page
* and separately discard the disk image in all cases.
*/
if (ref->page != NULL)
__wt_ref_out(session, ref);
WT_PUBLISH(ref->state, previous_state);
__wt_buf_free(session, &tmp);
return (ret);
}
/*
* __wt_las_sweep --
* Sweep the lookaside table.
*/
int
__wt_las_sweep(WT_SESSION_IMPL *session)
{
WT_CONNECTION_IMPL *conn;
WT_CURSOR *cursor;
WT_DECL_ITEM(las_addr);
WT_DECL_ITEM(las_key);
WT_DECL_RET;
WT_ITEM *key;
uint64_t cnt, las_counter, las_txnid;
int64_t remove_cnt;
uint32_t las_id, session_flags;
int notused;
conn = S2C(session);
cursor = NULL;
key = &conn->las_sweep_key;
remove_cnt = 0;
session_flags = 0; /* [-Werror=maybe-uninitialized] */
WT_ERR(__wt_scr_alloc(session, 0, &las_addr));
WT_ERR(__wt_scr_alloc(session, 0, &las_key));
WT_ERR(__wt_las_cursor(session, &cursor, &session_flags));
/*
* If we're not starting a new sweep, position the cursor using the key
* from the last call (we don't care if we're before or after the key,
* just roughly in the same spot is fine).
*/
if (key->size != 0) {
__wt_cursor_set_raw_key(cursor, key);
ret = cursor->search_near(cursor, ¬used);
/*
* Don't search for the same key twice; if we don't set a new
* key below, it's because we've reached the end of the table
* and we want the next pass to start at the beginning of the
* table. Searching for the same key could leave us stuck at
* the end of the table, repeatedly checking the same rows.
*/
key->size = 0;
if (ret != 0)
goto srch_notfound;
}
/*
* The sweep server wakes up every 10 seconds (by default), it's a slow
* moving thread. Try to review the entire lookaside table once every 5
* minutes, or every 30 calls.
*
* The reason is because the lookaside table exists because we're seeing
* cache/eviction pressure (it allows us to trade performance and disk
* space for cache space), and it's likely lookaside blocks are being
* evicted, and reading them back in doesn't help things. A trickier,
* but possibly better, alternative might be to review all lookaside
* blocks in the cache in order to get rid of them, and slowly review
* lookaside blocks that have already been evicted.
*/
cnt = (uint64_t)WT_MAX(100, conn->las_record_cnt / 30);
/* Discard pages we read as soon as we're done with them. */
F_SET(session, WT_SESSION_NO_CACHE);
/* Walk the file. */
for (; cnt > 0 && (ret = cursor->next(cursor)) == 0; --cnt) {
/*
* If the loop terminates after completing a work unit, we will
* continue the table sweep next time. Get a local copy of the
* sweep key, we're going to reset the cursor; do so before
* calling cursor.remove, cursor.remove can discard our hazard
* pointer and the page could be evicted from underneath us.
*/
if (cnt == 1) {
WT_ERR(__wt_cursor_get_raw_key(cursor, key));
if (!WT_DATA_IN_ITEM(key))
WT_ERR(__wt_buf_set(
session, key, key->data, key->size));
}
WT_ERR(cursor->get_key(cursor,
&las_id, las_addr, &las_counter, &las_txnid, las_key));
/*
* If the on-page record transaction ID associated with the
* record is globally visible, the record can be discarded.
*
* Cursor opened overwrite=true: won't return WT_NOTFOUND should
* another thread remove the record before we do, and the cursor
* remains positioned in that case.
*/
if (__wt_txn_visible_all(session, las_txnid)) {
WT_ERR(cursor->remove(cursor));
++remove_cnt;
}
}
srch_notfound:
WT_ERR_NOTFOUND_OK(ret);
if (0) {
err: __wt_buf_free(session, key);
}
WT_TRET(__wt_las_cursor_close(session, &cursor, session_flags));
/*
* If there were races to remove records, we can over-count. All
* arithmetic is signed, so underflow isn't fatal, but check anyway so
* we don't skew low over time.
*/
if (remove_cnt > S2C(session)->las_record_cnt)
S2C(session)->las_record_cnt = 0;
else if (remove_cnt > 0)
(void)__wt_atomic_subi64(&conn->las_record_cnt, remove_cnt);
F_CLR(session, WT_SESSION_NO_CACHE);
__wt_scr_free(session, &las_addr);
__wt_scr_free(session, &las_key);
return (ret);
}
/*
* __wt_las_sweep --
* Sweep the lookaside table.
*/
int
__wt_las_sweep(WT_SESSION_IMPL *session)
{
WT_CONNECTION_IMPL *conn;
WT_CURSOR *cursor;
WT_DECL_ITEM(las_addr);
WT_DECL_ITEM(las_key);
WT_DECL_RET;
WT_ITEM *key;
uint64_t cnt, las_counter, las_txnid;
uint32_t las_id, session_flags;
int notused;
conn = S2C(session);
cursor = NULL;
key = &conn->las_sweep_key;
session_flags = 0; /* [-Werror=maybe-uninitialized] */
WT_ERR(__wt_scr_alloc(session, 0, &las_addr));
WT_ERR(__wt_scr_alloc(session, 0, &las_key));
WT_ERR(__wt_las_cursor(session, &cursor, &session_flags));
/*
* If we're not starting a new sweep, position the cursor using the key
* from the last call (we don't care if we're before or after the key,
* just roughly in the same spot is fine).
*/
if (conn->las_sweep_call != 0 && key->data != NULL) {
__wt_cursor_set_raw_key(cursor, key);
if ((ret = cursor->search_near(cursor, ¬used)) != 0)
goto srch_notfound;
}
/*
* The sweep server wakes up every 10 seconds (by default), it's a slow
* moving thread. Try to review the entire lookaside table once every 5
* minutes, or every 30 calls.
*
* The reason is because the lookaside table exists because we're seeing
* cache/eviction pressure (it allows us to trade performance and disk
* space for cache space), and it's likely lookaside blocks are being
* evicted, and reading them back in doesn't help things. A trickier,
* but possibly better, alternative might be to review all lookaside
* blocks in the cache in order to get rid of them, and slowly review
* lookaside blocks that have already been evicted.
*
* We can't know for sure how many records are in the lookaside table,
* the cursor insert and remove statistics aren't updated atomically.
* Start with reviewing 100 rows, and if it takes more than the target
* number of calls to finish, increase the number of rows checked on
* each call; if it takes less than the target calls to finish, then
* decrease the number of rows reviewed on each call (but never less
* than 100).
*/
#define WT_SWEEP_LOOKASIDE_MIN_CNT 100
#define WT_SWEEP_LOOKASIDE_PASS_TARGET 30
++conn->las_sweep_call;
if ((cnt = conn->las_sweep_cnt) < WT_SWEEP_LOOKASIDE_MIN_CNT)
cnt = conn->las_sweep_cnt = WT_SWEEP_LOOKASIDE_MIN_CNT;
/* Walk the file. */
for (; cnt > 0 && (ret = cursor->next(cursor)) == 0; --cnt) {
/*
* If the loop terminates after completing a work unit, we will
* continue the table sweep next time. Get a local copy of the
* sweep key, we're going to reset the cursor; do so before
* calling cursor.remove, cursor.remove can discard our hazard
* pointer and the page could be evicted from underneath us.
*/
if (cnt == 1) {
WT_ERR(__wt_cursor_get_raw_key(cursor, key));
if (!WT_DATA_IN_ITEM(key))
WT_ERR(__wt_buf_set(
session, key, key->data, key->size));
}
WT_ERR(cursor->get_key(cursor,
&las_id, las_addr, &las_counter, &las_txnid, las_key));
/*
* If the on-page record transaction ID associated with the
* record is globally visible, the record can be discarded.
*
* Cursor opened overwrite=true: won't return WT_NOTFOUND should
* another thread remove the record before we do, and the cursor
* remains positioned in that case.
*/
if (__wt_txn_visible_all(session, las_txnid))
WT_ERR(cursor->remove(cursor));
}
/*
* When reaching the lookaside table end or the target number of calls,
* adjust the row count. Decrease/increase the row count depending on
* if the number of calls is less/more than the target.
*/
if (ret == WT_NOTFOUND ||
conn->las_sweep_call > WT_SWEEP_LOOKASIDE_PASS_TARGET) {
if (conn->las_sweep_call < WT_SWEEP_LOOKASIDE_PASS_TARGET &&
conn->las_sweep_cnt > WT_SWEEP_LOOKASIDE_MIN_CNT)
conn->las_sweep_cnt -= WT_SWEEP_LOOKASIDE_MIN_CNT;
if (conn->las_sweep_call > WT_SWEEP_LOOKASIDE_PASS_TARGET)
conn->las_sweep_cnt += WT_SWEEP_LOOKASIDE_MIN_CNT;
}
srch_notfound:
if (ret == WT_NOTFOUND)
conn->las_sweep_call = 0;
WT_ERR_NOTFOUND_OK(ret);
if (0) {
err: __wt_buf_free(session, key);
}
WT_TRET(__wt_las_cursor_close(session, &cursor, session_flags));
__wt_scr_free(session, &las_addr);
__wt_scr_free(session, &las_key);
return (ret);
}
/*
* __wt_cache_read --
* Read a page from the file.
*/
int
__wt_cache_read(WT_SESSION_IMPL *session, WT_REF *ref)
{
WT_DECL_RET;
WT_ITEM tmp;
WT_PAGE *page;
WT_PAGE_STATE previous_state;
size_t addr_size;
const uint8_t *addr;
page = NULL;
/*
* Don't pass an allocated buffer to the underlying block read function,
* force allocation of new memory of the appropriate size.
*/
WT_CLEAR(tmp);
/*
* Attempt to set the state to WT_REF_READING for normal reads, or
* WT_REF_LOCKED, for deleted pages. If successful, we've won the
* race, read the page.
*/
if (WT_ATOMIC_CAS4(ref->state, WT_REF_DISK, WT_REF_READING))
previous_state = WT_REF_DISK;
else if (WT_ATOMIC_CAS4(ref->state, WT_REF_DELETED, WT_REF_LOCKED))
previous_state = WT_REF_DELETED;
else
return (0);
/*
* Get the address: if there is no address, the page was deleted, but a
* subsequent search or insert is forcing re-creation of the name space.
* Otherwise, there's an address, read the backing disk page and build
* an in-memory version of the page.
*/
WT_ERR(__wt_ref_info(session, ref, &addr, &addr_size, NULL));
if (addr == NULL) {
WT_ASSERT(session, previous_state == WT_REF_DELETED);
WT_ERR(__wt_btree_new_leaf_page(session, &page));
ref->page = page;
} else {
/* Read the backing disk page. */
WT_ERR(__wt_bt_read(session, &tmp, addr, addr_size));
/* Build the in-memory version of the page. */
WT_ERR(__wt_page_inmem(session, ref, tmp.data,
WT_DATA_IN_ITEM(&tmp) ?
WT_PAGE_DISK_ALLOC : WT_PAGE_DISK_MAPPED, &page));
/* If the page was deleted, instantiate that information. */
if (previous_state == WT_REF_DELETED)
WT_ERR(__wt_delete_page_instantiate(session, ref));
}
WT_ERR(__wt_verbose(session, WT_VERB_READ,
"page %p: %s", page, __wt_page_type_string(page->type)));
WT_PUBLISH(ref->state, WT_REF_MEM);
return (0);
err: /*
* If the function building an in-memory version of the page failed,
* it discarded the page, but not the disk image. Discard the page
* and separately discard the disk image in all cases.
*/
if (ref->page != NULL)
__wt_ref_out(session, ref);
WT_PUBLISH(ref->state, previous_state);
__wt_buf_free(session, &tmp);
return (ret);
}
/*
* __clsm_enter --
* Start an operation on an LSM cursor, update if the tree has changed.
*/
static inline int
__clsm_enter(WT_CURSOR_LSM *clsm, int reset, int update)
{
WT_CURSOR *c;
WT_DECL_RET;
WT_LSM_CHUNK *chunk;
WT_SESSION_IMPL *session;
uint64_t *txnid_maxp;
uint64_t id, myid, snap_min;
session = (WT_SESSION_IMPL *)clsm->iface.session;
/* Merge cursors never update. */
if (F_ISSET(clsm, WT_CLSM_MERGE))
return (0);
if (reset) {
c = &clsm->iface;
/* Copy out data before resetting chunk cursors. */
if (F_ISSET(c, WT_CURSTD_KEY_INT) &&
!WT_DATA_IN_ITEM(&c->key))
WT_RET(__wt_buf_set(
session, &c->key, c->key.data, c->key.size));
if (F_ISSET(c, WT_CURSTD_VALUE_INT) &&
!WT_DATA_IN_ITEM(&c->value))
WT_RET(__wt_buf_set(
session, &c->value, c->value.data, c->value.size));
WT_RET(__clsm_reset_cursors(clsm, NULL));
}
for (;;) {
/*
* If the cursor looks up-to-date, check if the cache is full.
* In case this call blocks, the check will be repeated before
* proceeding.
*/
if (clsm->dsk_gen != clsm->lsm_tree->dsk_gen)
goto open;
WT_RET(__wt_cache_full_check(session));
if (clsm->dsk_gen != clsm->lsm_tree->dsk_gen)
goto open;
/* Update the maximum transaction ID in the primary chunk. */
if (update && (chunk = clsm->primary_chunk) != NULL) {
WT_RET(__wt_txn_autocommit_check(session));
for (id = chunk->txnid_max, myid = session->txn.id;
!TXNID_LE(myid, id);
id = chunk->txnid_max) {
WT_ASSERT(session, myid != WT_TXN_NONE);
(void)WT_ATOMIC_CAS(
chunk->txnid_max, id, myid);
}
}
/*
* Figure out how many updates are required for snapshot
* isolation.
*
* This is not a normal visibility check on the maximum
* transaction ID in each chunk: any transaction ID that
* overlaps with our snapshot is a potential conflict.
*/
clsm->nupdates = 1;
if (session->txn.isolation == TXN_ISO_SNAPSHOT &&
F_ISSET(clsm, WT_CLSM_OPEN_SNAPSHOT)) {
snap_min = session->txn.snap_min;
for (txnid_maxp = &clsm->txnid_max[clsm->nchunks - 2];
clsm->nupdates < clsm->nchunks;
clsm->nupdates++, txnid_maxp--)
if (TXNID_LT(*txnid_maxp, snap_min))
break;
}
/*
* Stop when we are up-to-date, as long as this is:
* - a snapshot isolation update and the cursor is set up for
* that;
* - an update operation with a primary chunk, or
* - a read operation and the cursor is open for reading.
*/
if ((!update ||
session->txn.isolation != TXN_ISO_SNAPSHOT ||
F_ISSET(clsm, WT_CLSM_OPEN_SNAPSHOT)) &&
((update && clsm->primary_chunk != NULL) ||
(!update && F_ISSET(clsm, WT_CLSM_OPEN_READ))))
break;
open: WT_WITH_SCHEMA_LOCK(session,
ret = __clsm_open_cursors(clsm, update, 0, 0));
WT_RET(ret);
}
if (!F_ISSET(clsm, WT_CLSM_ACTIVE)) {
WT_RET(__cursor_enter(session));
F_SET(clsm, WT_CLSM_ACTIVE);
}
return (0);
}
/*
* __clsm_open_cursors --
* Open cursors for the current set of files.
*/
static int
__clsm_open_cursors(
WT_CURSOR_LSM *clsm, int update, u_int start_chunk, uint32_t start_id)
{
WT_CURSOR *c, **cp, *primary;
WT_DECL_RET;
WT_LSM_CHUNK *chunk;
WT_LSM_TREE *lsm_tree;
WT_SESSION_IMPL *session;
WT_TXN *txn;
const char *checkpoint, *ckpt_cfg[3];
uint64_t saved_gen;
u_int i, nchunks, ngood, nupdates;
int locked;
c = &clsm->iface;
session = (WT_SESSION_IMPL *)c->session;
txn = &session->txn;
lsm_tree = clsm->lsm_tree;
chunk = NULL;
ckpt_cfg[0] = WT_CONFIG_BASE(session, session_open_cursor);
ckpt_cfg[1] = "checkpoint=" WT_CHECKPOINT ",raw";
ckpt_cfg[2] = NULL;
/* Copy the key, so we don't lose the cursor position. */
if (F_ISSET(c, WT_CURSTD_KEY_INT) && !WT_DATA_IN_ITEM(&c->key))
WT_RET(__wt_buf_set(
session, &c->key, c->key.data, c->key.size));
F_CLR(clsm, WT_CLSM_ITERATE_NEXT | WT_CLSM_ITERATE_PREV);
if (update) {
if (txn->isolation == TXN_ISO_SNAPSHOT)
F_SET(clsm, WT_CLSM_OPEN_SNAPSHOT);
} else
F_SET(clsm, WT_CLSM_OPEN_READ);
WT_RET(__wt_lsm_tree_lock(session, lsm_tree, 0));
locked = 1;
/*
* If there is no in-memory chunk in the tree for an update operation,
* create one.
*
* !!!
* It is exceeding unlikely that we get here at all, but if there is a
* transaction in progress and it rolls back, it would leave the
* metadata inconsistent.
*/
if (update && (lsm_tree->nchunks == 0 ||
(chunk = lsm_tree->chunk[lsm_tree->nchunks - 1]) == NULL ||
F_ISSET(chunk, WT_LSM_CHUNK_ONDISK))) {
/* Release our lock because switch will get a write lock. */
locked = 0;
WT_ERR(__wt_lsm_tree_unlock(session, lsm_tree));
WT_ERR(__wt_lsm_tree_switch(session, lsm_tree));
WT_ERR(__wt_lsm_tree_lock(session, lsm_tree, 0));
locked = 1;
}
F_SET(session, WT_SESSION_NO_CACHE_CHECK);
/* Merge cursors have already figured out how many chunks they need. */
retry: if (F_ISSET(clsm, WT_CLSM_MERGE)) {
nchunks = clsm->nchunks;
ngood = 0;
/*
* We may have raced with another merge completing. Check that
* we're starting at the right offset in the chunk array.
*/
if (start_chunk >= lsm_tree->nchunks ||
lsm_tree->chunk[start_chunk]->id != start_id) {
for (start_chunk = 0;
start_chunk < lsm_tree->nchunks;
start_chunk++) {
chunk = lsm_tree->chunk[start_chunk];
if (chunk->id == start_id)
break;
}
/* We have to find the start chunk: merge locked it. */
WT_ASSERT(session, start_chunk < lsm_tree->nchunks);
}
WT_ASSERT(session, start_chunk + nchunks <= lsm_tree->nchunks);
} else {
nchunks = lsm_tree->nchunks;
/*
* If we are only opening the cursor for updates, only open the
* primary chunk, plus any other chunks that might be required
* to detect snapshot isolation conflicts.
*/
if (F_ISSET(clsm, WT_CLSM_OPEN_SNAPSHOT))
WT_ERR(__wt_realloc_def(session,
&clsm->txnid_alloc, nchunks,
&clsm->txnid_max));
if (F_ISSET(clsm, WT_CLSM_OPEN_READ))
ngood = nupdates = 0;
else if (F_ISSET(clsm, WT_CLSM_OPEN_SNAPSHOT)) {
/*
* Keep going until all updates in the next
* chunk are globally visible. Copy the maximum
* transaction IDs into the cursor as we go.
*/
for (ngood = nchunks - 1, nupdates = 1;
ngood > 0;
ngood--, nupdates++) {
chunk = lsm_tree->chunk[ngood - 1];
clsm->txnid_max[ngood - 1] =
chunk->txnid_max;
if (__wt_txn_visible_all(
session, chunk->txnid_max))
break;
}
} else {
nupdates = 1;
ngood = nchunks - 1;
}
/* Check how many cursors are already open. */
for (cp = clsm->cursors + ngood;
ngood < clsm->nchunks && ngood < nchunks;
cp++, ngood++) {
chunk = lsm_tree->chunk[ngood];
/* If the cursor isn't open yet, we're done. */
if (*cp == NULL)
break;
/* Easy case: the URIs don't match. */
if (strcmp((*cp)->uri, chunk->uri) != 0)
break;
/* Make sure the checkpoint config matches. */
checkpoint = ((WT_CURSOR_BTREE *)*cp)->
btree->dhandle->checkpoint;
if (checkpoint == NULL &&
F_ISSET(chunk, WT_LSM_CHUNK_ONDISK) &&
!chunk->empty)
break;
/* Make sure the Bloom config matches. */
if (clsm->blooms[ngood] == NULL &&
F_ISSET(chunk, WT_LSM_CHUNK_BLOOM))
break;
}
/* Spurious generation bump? */
if (ngood == clsm->nchunks && clsm->nchunks == nchunks) {
clsm->dsk_gen = lsm_tree->dsk_gen;
goto err;
}
/*
* Close any cursors we no longer need.
*
* Drop the LSM tree lock while we do this: if the cache is
* full, we may block while closing a cursor. Save the
* generation number and retry if it has changed under us.
*/
if (clsm->cursors != NULL && (ngood < clsm->nchunks ||
(!F_ISSET(clsm, WT_CLSM_OPEN_READ) && nupdates > 0))) {
saved_gen = lsm_tree->dsk_gen;
locked = 0;
WT_ERR(__wt_lsm_tree_unlock(session, lsm_tree));
if (!F_ISSET(clsm, WT_CLSM_OPEN_READ) && nupdates > 0)
WT_ERR(__clsm_close_cursors(
clsm, 0, nchunks - nupdates));
WT_ERR(__clsm_close_cursors(
clsm, ngood, clsm->nchunks));
WT_ERR(__wt_lsm_tree_lock(session, lsm_tree, 0));
locked = 1;
if (lsm_tree->dsk_gen != saved_gen)
goto retry;
}
/* Detach from our old primary. */
clsm->primary_chunk = NULL;
clsm->current = NULL;
}
WT_ERR(__wt_realloc_def(session,
&clsm->bloom_alloc, nchunks, &clsm->blooms));
WT_ERR(__wt_realloc_def(session,
&clsm->cursor_alloc, nchunks, &clsm->cursors));
clsm->nchunks = nchunks;
/* Open the cursors for chunks that have changed. */
for (i = ngood, cp = clsm->cursors + i; i != nchunks; i++, cp++) {
chunk = lsm_tree->chunk[i + start_chunk];
/* Copy the maximum transaction ID. */
if (F_ISSET(clsm, WT_CLSM_OPEN_SNAPSHOT))
clsm->txnid_max[i] = chunk->txnid_max;
/*
* Read from the checkpoint if the file has been written.
* Once all cursors switch, the in-memory tree can be evicted.
*/
WT_ASSERT(session, *cp == NULL);
ret = __wt_open_cursor(session, chunk->uri, c,
(F_ISSET(chunk, WT_LSM_CHUNK_ONDISK) && !chunk->empty) ?
ckpt_cfg : NULL, cp);
/*
* XXX kludge: we may have an empty chunk where no checkpoint
* was written. If so, try to open the ordinary handle on that
* chunk instead.
*/
if (ret == WT_NOTFOUND &&
F_ISSET(chunk, WT_LSM_CHUNK_ONDISK)) {
ret = __wt_open_cursor(
session, chunk->uri, c, NULL, cp);
if (ret == 0)
chunk->empty = 1;
}
WT_ERR(ret);
if (F_ISSET(chunk, WT_LSM_CHUNK_BLOOM) &&
!F_ISSET(clsm, WT_CLSM_MERGE))
WT_ERR(__wt_bloom_open(session, chunk->bloom_uri,
lsm_tree->bloom_bit_count,
lsm_tree->bloom_hash_count,
c, &clsm->blooms[i]));
/* Child cursors always use overwrite and raw mode. */
F_SET(*cp, WT_CURSTD_OVERWRITE | WT_CURSTD_RAW);
}
/* The last chunk is our new primary. */
if (chunk != NULL && !F_ISSET(chunk, WT_LSM_CHUNK_ONDISK)) {
clsm->primary_chunk = chunk;
primary = clsm->cursors[clsm->nchunks - 1];
WT_WITH_BTREE(session, ((WT_CURSOR_BTREE *)(primary))->btree,
__wt_btree_evictable(session, 0));
}
clsm->dsk_gen = lsm_tree->dsk_gen;
err: F_CLR(session, WT_SESSION_NO_CACHE_CHECK);
#ifdef HAVE_DIAGNOSTIC
/* Check that all cursors are open as expected. */
if (ret == 0 && F_ISSET(clsm, WT_CLSM_OPEN_READ)) {
for (i = 0, cp = clsm->cursors; i != clsm->nchunks; cp++, i++) {
chunk = lsm_tree->chunk[i + start_chunk];
/* Make sure the cursor is open. */
WT_ASSERT(session, *cp != NULL);
/* Easy case: the URIs should match. */
WT_ASSERT(session, strcmp((*cp)->uri, chunk->uri) == 0);
/* Make sure the checkpoint config matches. */
checkpoint = ((WT_CURSOR_BTREE *)*cp)->
btree->dhandle->checkpoint;
WT_ASSERT(session,
(F_ISSET(chunk, WT_LSM_CHUNK_ONDISK) &&
!chunk->empty) ?
checkpoint != NULL : checkpoint == NULL);
/* Make sure the Bloom config matches. */
WT_ASSERT(session,
(F_ISSET(chunk, WT_LSM_CHUNK_BLOOM) &&
!F_ISSET(clsm, WT_CLSM_MERGE)) ?
clsm->blooms[i] != NULL : clsm->blooms[i] == NULL);
}
}
#endif
if (locked)
WT_TRET(__wt_lsm_tree_unlock(session, lsm_tree));
return (ret);
}
