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Type: Task
Resolution: Done
Fix Version/s: WT1.5.0
Affects Version/s: None
Component/s: None
Labels:
None

Case:

I've assigned this to Michael because it appears to be in the btree code rather than the eviction code. Turf as appropriate.

In testing various parameterization changes to the benchmark hang running with a small cache in ~~WT-440~~, I bumped the cache up to the minimum required if LSM used 4 chunks minimum instead of 3 (about 8Mb). The read portion of that test does not hang, but goes slowly, as expected.

In thinking that we're just moving the problem, I ran the same ~8Mb cache, but with 8 threads. With that, it takes a segfault in the overwrite part of the test.

Here is the command line to execute, modulo your own env and pathname needs:

env DYLD_LIBRARY_PATH=../wiredtiger/build_posix/.libs:../wiredtiger/build_posix/ext/compressors/snappy/.libs/ TEST_TMPDIR= ./db_bench_wiredtiger --threads=8 --cache_size=8450048 --benchmarks=fillrandom,overwrite

Here is the stack:

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000050
[Switching to process 5763 thread 0x2b07]
0x00000001056ed4a7 in __wt_row_search (session=0x7fd1440026c0, cbt=0x7fd147327b90, is_modify=1) at row_srch.c:131
131		    page = btree->root_page; page->type == WT_PAGE_ROW_INT; ++depth) {
(gdb) bt
#0  0x00000001056ed4a7 in __wt_row_search (session=0x7fd1440026c0, cbt=0x7fd147327b90, is_modify=1) at row_srch.c:131
WT-1  0x00000001056af918 in __wt_btcur_insert (cbt=0x7fd147327b90) at bt_cursor.c:314
WT-2  0x00000001056fdc15 in __curfile_insert (cursor=0x7fd147327b90) at cur_file.c:175
WT-3  0x0000000105719c9b in __wt_metadata_update (session=0x7fd1440026c0, key=0x7fd143902ae0 "lsm:dbbench_wt-2", value=0x7fd1460af800 "bloom_config=(),file_config=(key_format=S,value_format=S,prefix_compression=false,checksum=off,internal_page_max=4kb,leaf_page_max=4kb,memory_page_max=8450048,block_compressor=snappy,key_format=u,valu"...) at meta_table.c:169
WT-4  0x0000000105712a83 in __wt_lsm_meta_write (session=0x7fd1440026c0, lsm_tree=0x7fd143902590) at lsm_meta.c:211
WT-5  0x0000000105715818 in __wt_lsm_tree_switch (session=0x7fd1440026c0, lsm_tree=0x7fd143902590) at lsm_tree.c:553
WT-6  0x000000010570e588 in __clsm_put (session=0x7fd1440026c0, clsm=0x7fd1474e5720, key=0x7fd1474e57d8, value=0x7fd1474e57f8) at lsm_cursor.c:849
WT-7  0x000000010570e013 in __clsm_insert (cursor=0x7fd1474e5720) at lsm_cursor.c:879
WT-8  0x000000010562102c in DoWrite (this=0x7fff5a5e3888, thread=0x7fd1460b6600, seq=false) at db_bench_wiredtiger.cc:898
WT-9  0x0000000105621556 in WriteRandom (this=0x7fff5a5e3888, thread=0x7fd1460b6600) at db_bench_wiredtiger.cc:849

Here are some of the interesting data structures:

(gdb) p/x *btree
$2 = {
  rwlock = 0x7fd143901930, 
  refcnt = 0xc, 
  q = {
    tqe_next = 0x7fd143902d00, 
    tqe_prev = 0x7fd1440013f8
  }, 
  name = 0x7fd143901290, 
  checkpoint = 0x0, 
  config = 0x7fd1439012b0, 
  stats = 0x7fd144014000, 
  maximum_depth = 0x3, 
  ckpt = 0x0, 
  type = 0x3, 
  key_format = 0x7fd1439002b0, 
  value_format = 0x7fd143900130, 
  bitcnt = 0x0, 
  collator = 0x0, 
  key_gap = 0xa, 
  allocsize = 0x200, 
  maxintlpage = 0x800, 
  maxintlitem = 0xc0, 
  maxleafpage = 0x100000, 
  maxleafitem = 0x18000, 
  maxmempage = 0x3200000, 
  huffman_key = 0x0, 
  huffman_value = 0x0, 
  checksum = 0x1, 
  dictionary = 0x0, 
  internal_key_truncate = 0x1, 
  prefix_compression = 0x1, 
  split_pct = 0x4b, 
  compressor = 0x0, 
  val_ovfl_lock = 0x7fd143901d20, 
  last_recno = 0x0, 
  root_page = 0x0, 
  modified = 0x1, 
  bulk_load_ok = 0x0, 
  block = 0x7fd144014600, 
  block_header = 0xc, 
  write_gen = 0xf24, 
  evict_page = 0x0, 
  evict_priority = 0x0, 
  lru_count = 0x0, 
  checkpointing = 0x0, 
  flags = 0xe0
}
(gdb) p/x *btree->root_page
Cannot access memory at address 0x0
(gdb) p depth
$3 = 2
(gdb) p/x *session
$4 = {
  iface = {
    connection = 0x7fd144001000, 
    close = 0x105732840, 
    reconfigure = 0x105732ed0, 
    open_cursor = 0x1057335a0, 
    create = 0x105733990, 
    compact = 0x105734050, 
    drop = 0x105734300, 
    rename = 0x105733bd0, 
    salvage = 0x105734520, 
    truncate = 0x105734770, 
    upgrade = 0x105734eb0, 
    verify = 0x105735100, 
    begin_transaction = 0x105735350, 
    commit_transaction = 0x1057355b0, 
    rollback_transaction = 0x105735840, 
    checkpoint = 0x105735a70, 
    msg_printf = 0x105735d30
  }, 
  active = 0x1, 
  cond = 0x7fd1426f4230, 
  name = 0x10574748f, 
  event_handler = 0x105761840, 
  btree = 0x7fd143901810, 
  btrees = {
    tqh_first = 0x7fd1478a3aa0, 
    tqh_last = 0x7fd1474e5868
  }, 
  cursor = 0x7fd147327b90, 
  cursors = {
    tqh_first = 0x7fd147327b90, 
    tqh_last = 0x7fd143b08980
  }, 
  metafile = 0x7fd143901810, 
  meta_track = 0x7fd14760e1c0, 
  meta_track_next = 0x0, 
  meta_track_sub = 0x0, 
  meta_track_alloc = 0x320, 
  meta_track_nest = 0x0, 
  tables = {
    tqh_first = 0x0, 
    tqh_last = 0x0
  }, 
  logrec_buf = {
    data = 0x0, 
    size = 0x0, 
    flags = 0x0, 
    mem = 0x0, 
    memsize = 0x0
  }, 
  logprint_buf = {
    data = 0x0, 
    size = 0x0, 
    flags = 0x0, 
    mem = 0x0, 
    memsize = 0x0
  }, 
  scratch = 0x7fd147634310, 
  scratch_alloc = 0xa, 
  scratch_track = 0x7fd1478b8060, 
  isolation = 0x1, 
  txn = {
    id = 0x96dae3, 
    isolation = 0x1, 
    snap_min = 0x96dadd, 
    snap_max = 0x96dae2, 
    snapshot = 0x7fd1426f42b0, 
    snapshot_count = 0x6, 
    oldest_snap_min = 0x968f2d, 
    mod = 0x7fd147591c90, 
    mod_alloc = 0x50, 
    mod_count = 0x2, 
    modref = 0x0, 
    modref_alloc = 0x0, 
    modref_count = 0x0, 
    eviction_fails = 0x0, 
    flags = 0x8
  }, 
  ncursors = 0x2, 
  reconcile = 0x7fd1473b51f0, 
  excl = 0x0, 
  excl_next = 0x0, 
  excl_allocated = 0x0, 
  syncop = 0x0, 
  syncop_ret = 0x0, 
  id = 0x8, 
  flags = 0x1, 
  hazard_size = 0xa, 
  nhazard = 0x1, 
  hazard = 0x7fd14403b000
}
(gdb) p/x *cbt
$6 = {
  iface = {
    session = 0x7fd1440026c0, 
    uri = 0x7fd143901290, 
    key_format = 0x7fd1439002b0, 
    value_format = 0x7fd143900130, 
    get_key = 0x105703090, 
    get_value = 0x105703fe0, 
    set_key = 0x105703220, 
    set_value = 0x1057043e0, 
    compare = 0x1056fcd90, 
    next = 0x1056fd0d0, 
    prev = 0x1056fd2f0, 
    reset = 0x1056fd400, 
    search = 0x1056fd510, 
    search_near = 0x1056fd700, 
    insert = 0x1056fd900, 
    update = 0x1056fdd80, 
    remove = 0x1056fe1f0, 
    close = 0x1056fe610, 
    q = {
      tqe_next = 0x7fd1474e5720, 
      tqe_prev = 0x7fd144002788
    }, 
    recno = 0x0, 
    raw_recno_buf = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, 
    key = {
      data = 0x7fd143902ae0, 
      size = 0x11, 
      flags = 0x0, 
      mem = 0x0, 
      memsize = 0x0
    }, 
    value = {
      data = 0x7fd1460af800, 
      size = 0x1931, 
      flags = 0x0, 
      mem = 0x0, 
      memsize = 0x0
    }, 
    saved_err = 0x0, 
    flags = 0x168
  }, 
  btree = 0x7fd143901810, 
  page = 0x0, 
  slot = 0xffffffff, 
  ins_head = 0x0, 
  ins = 0x0, 
  ins_stack = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, 
  next_stack = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, 
  recno = 0x0, 
  write_gen = 0x0, 
  compare = 0x2, 
  last_standard_recno = 0x0, 
  row_iteration_slot = 0x0, 
  cip_saved = 0x0, 
  rip_saved = 0x0, 
  tmp = {
    data = 0x0, 
    size = 0x0, 
    flags = 0x0, 
    mem = 0x0, 
    memsize = 0x0
  }, 
  v = 0x0, 
  flags = 0x1
}

is related to

WT-440 Hang under LevelDB benchmark "small" config with 4 or more threads.

Closed

WT-441 Allow LSM trees to discard the btree handle from the active chunk.

Closed

related to

WT-1 placeholder WT-1

Closed

WT-2 What does metadata look like?

Closed

WT-3 What file formats are required?

Closed

WT-5 How does pget work: is it necessary?

Closed

WT-6 Complex schema example

Closed

WT-7 Do we need the handle->err/errx methods?

Closed

WT-8 Do we need table load, bulk-load and/or dump methods?

Closed

WT-9 Does adding schema need to be transactional?

Closed

(5 related to)

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