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Commit b6df44dc authored by Rusty Russell's avatar Rusty Russell
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tdb2: update design.lyx

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ccan/tdb2/doc/design.lyx
View file @ b6df44dc
......@@ -698,7 +698,13 @@ Status
\end_layout
\begin_layout Standard
\change_deleted 0 1298979572
Incomplete; nesting flag is still defined as per tdb1.
\change_inserted 0 1298979584
Complete; the nesting flag has been removed.
\change_unchanged
\end_layout
\begin_layout Subsection
......@@ -870,14 +876,32 @@ Proposed Solution
\begin_layout Standard
Reachitecting the API to include a tdb_errcode pointer would be a great
deal of churn; we are better to guarantee that the tdb_errcode is per-thread
so the current programming model can be maintained.
deal of churn
\change_inserted 0 1298979557
, but fortunately most functions return 0 on success and -1 on error: we
can change these to return 0 on success and a negative error code on error,
and the API remains similar to previous.
The tdb_fetch, tdb_firstkey and tdb_nextkey functions need to take a TDB_DATA
pointer and return an error code.
It is also simpler to have tdb_nextkey replace its key argument in place,
freeing up any old .dptr.
\end_layout
\begin_layout Standard
\change_deleted 0 1298979438
; we are better to guarantee that the tdb_errcode is per-thread so the current
programming model can be maintained.
\end_layout
\begin_layout Standard
\change_deleted 0 1298979438
This requires dynamic per-thread allocations, which is awkward with POSIX
threads (pthread_key_create space is limited and we cannot simply allocate
a key for every TDB).
\change_unchanged
\end_layout
\begin_layout Standard
......@@ -903,7 +927,13 @@ Status
\end_layout
\begin_layout Standard
Incomplete.
Incomplete
\change_inserted 0 1298979681
; API has been changed but thread safety has not been implemented.
\change_deleted 0 1298979669
.
\change_unchanged
\end_layout
\begin_layout Subsection
......@@ -1291,7 +1321,13 @@ Status
\end_layout
\begin_layout Standard
\change_deleted 0 1298979699
Incomplete, TDB_CLEAR_IF_FIRST still defined, but not implemented.
\change_inserted 0 1298979700
Complete.
\change_unchanged
\end_layout
\begin_layout Subsection
......@@ -1497,7 +1533,13 @@ Status
\end_layout
\begin_layout Standard
\change_deleted 0 1298979837
Incomplete; TDB_CLEAR_IF_FIRST still defined, but does nothing.
\change_inserted 0 1298979837
Complete.
\change_unchanged
\end_layout
\begin_layout Subsection
......
ccan/tdb2/doc/design.lyx,v
View file @ b6df44dc
......@@ -6,7 +6,7 @@ comment @# @;
1.13
date 2010.12.01.12.22.08; author rusty; state Exp;
date 2011.03.01.11.46.54; author rusty; state Exp;
branches;
next 1.12;
......@@ -78,7 +78,7 @@ desc
1.13
log
@Merged changes.
@Thread-safe API
@
text
@#LyX 1.6.7 created this file. For more info see http://www.lyx.org/
......@@ -781,7 +781,13 @@ Status
\end_layout
\begin_layout Standard
\change_deleted 0 1298979572
Incomplete; nesting flag is still defined as per tdb1.
\change_inserted 0 1298979584
Complete; the nesting flag has been removed.
\change_unchanged
\end_layout
\begin_layout Subsection
......@@ -953,14 +959,32 @@ Proposed Solution
\begin_layout Standard
Reachitecting the API to include a tdb_errcode pointer would be a great
deal of churn; we are better to guarantee that the tdb_errcode is per-thread
so the current programming model can be maintained.
deal of churn
\change_inserted 0 1298979557
, but fortunately most functions return 0 on success and -1 on error: we
can change these to return 0 on success and a negative error code on error,
and the API remains similar to previous.
The tdb_fetch, tdb_firstkey and tdb_nextkey functions need to take a TDB_DATA
pointer and return an error code.
It is also simpler to have tdb_nextkey replace its key argument in place,
freeing up any old .dptr.
\end_layout
\begin_layout Standard
\change_deleted 0 1298979438
; we are better to guarantee that the tdb_errcode is per-thread so the current
programming model can be maintained.
\end_layout
\begin_layout Standard
\change_deleted 0 1298979438
This requires dynamic per-thread allocations, which is awkward with POSIX
threads (pthread_key_create space is limited and we cannot simply allocate
a key for every TDB).
\change_unchanged
\end_layout
\begin_layout Standard
......@@ -986,7 +1010,13 @@ Status
\end_layout
\begin_layout Standard
Incomplete.
Incomplete
\change_inserted 0 1298979681
; API has been changed but thread safety has not been implemented.
\change_deleted 0 1298979669
.
\change_unchanged
\end_layout
\begin_layout Subsection
......@@ -1374,7 +1404,13 @@ Status
\end_layout
\begin_layout Standard
\change_deleted 0 1298979699
Incomplete, TDB_CLEAR_IF_FIRST still defined, but not implemented.
\change_inserted 0 1298979700
Complete.
\change_unchanged
\end_layout
\begin_layout Subsection
......@@ -1580,7 +1616,13 @@ Status
\end_layout
\begin_layout Standard
\change_deleted 0 1298979837
Incomplete; TDB_CLEAR_IF_FIRST still defined, but does nothing.
\change_inserted 0 1298979837
Complete.
\change_unchanged
\end_layout
\begin_layout Subsection
......@@ -2822,211 +2864,210 @@ a693 2
a696 2
\change_inserted 0 1291204640
a700 2
d702 1
a702 1
\change_inserted 0 1291204665
a701 2
\change_unchanged
a722 2
d704 2
a728 2
\change_inserted 0 1291204671
a725 2
a731 2
\change_inserted 0 1291204671
a729 2
a735 2
\change_inserted 0 1291204673
a730 2
a736 2
\change_unchanged
a774 2
a780 2
\change_inserted 0 1291204731
a777 2
a783 2
\change_inserted 0 1291204732
a781 2
a787 2
\change_inserted 0 1291204779
a784 2
a790 2
\change_unchanged
a836 2
a842 2
\change_inserted 0 1291204830
a839 2
a845 2
\change_inserted 0 1291204831
a843 2
a849 2
\change_inserted 0 1291204834
a844 2
a850 2
\change_unchanged
a898 2
d879 9
a887 2
deal of churn; we are better to guarantee that the tdb_errcode is per-thread
so the current programming model can be maintained.
d891 9
d903 2
a922 2
\change_inserted 0 1291204847
a901 2
a925 2
\change_inserted 0 1291204847
a905 2
d930 5
a934 3
\change_inserted 0 1291204852
a906 2
\change_unchanged
a1021 2
Incomplete.
a1051 2
\change_inserted 0 1291204881
a1024 2
a1054 2
\change_inserted 0 1291204881
a1028 2
a1058 2
\change_inserted 0 1291204885
a1029 2
a1059 2
\change_unchanged
a1110 2
a1140 2
\change_inserted 0 1291204898
a1113 2
a1143 2
\change_inserted 0 1291204898
a1117 2
a1147 2
\change_inserted 0 1291204901
a1118 2
a1148 2
\change_unchanged
a1194 2
a1224 2
\change_inserted 0 1291204908
a1197 2
a1227 2
\change_inserted 0 1291204908
a1201 2
a1231 2
\change_inserted 0 1291204908
a1202 2
a1232 2
\change_unchanged
a1241 2
a1271 2
\change_inserted 0 1291204917
a1244 2
a1274 2
\change_inserted 0 1291204917
a1248 2
a1278 2
\change_inserted 0 1291204920
a1249 2
a1279 2
\change_unchanged
a1286 2
a1316 2
\change_inserted 0 1291204927
a1289 2
a1319 2
\change_inserted 0 1291204928
a1293 2
d1325 1
a1325 1
\change_inserted 0 1291204942
a1294 2
\change_unchanged
a1345 2
d1327 2
a1381 2
\change_inserted 0 1291205003
a1348 2
a1384 2
\change_inserted 0 1291205004
a1352 2
a1388 2
\change_inserted 0 1291205007
a1375 2
a1411 2
\change_inserted 0 1291205019
a1378 2
a1414 2
\change_inserted 0 1291205019
a1382 2
a1418 2
\change_inserted 0 1291205023
a1383 2
a1419 2
\change_unchanged
a1429 2
a1465 2
\change_inserted 0 1291205029
a1432 2
a1468 2
\change_inserted 0 1291205029
a1436 2
a1472 2
\change_inserted 0 1291206020
a1437 2
a1473 2
\change_unchanged
a1492 2
a1528 2
\change_inserted 0 1291205043
a1495 2
a1531 2
\change_inserted 0 1291205043
a1499 2
d1537 1
a1537 1
\change_inserted 0 1291205057
a1500 2
\change_unchanged
a1547 2
d1539 2
a1589 2
\change_inserted 0 1291205062
a1550 2
a1592 2
\change_inserted 0 1291205062
a1554 2
a1596 2
\change_inserted 0 1291205062
a1555 2
a1597 2
\change_unchanged
a1584 2
a1626 2
\change_inserted 0 1291205072
a1587 2
a1629 2
\change_inserted 0 1291205073
a1591 2
a1633 2
\change_inserted 0 1291205073
a1592 2
a1634 2
\change_unchanged
a1632 4
a1674 4
\change_deleted 0 1291204504
\change_unchanged
a1657 2
a1699 2
\change_inserted 0 1291205079
a1660 2
a1702 2
\change_inserted 0 1291205080
a1664 2
a1706 2
\change_inserted 0 1291205080
a1665 2
a1707 2
\change_unchanged
a1791 2
a1833 2
\change_inserted 0 1291205090
d1827 2
a1828 7
d1869 2
a1870 7
is to divide the file into zones, and using a free list (or
\change_inserted 0 1291205498
table
......@@ -3034,13 +3075,13 @@ table
set
\change_unchanged
of free lists) for each.
a1829 2
a1871 2
\change_inserted 0 1291205203
a1832 2
a1874 2
\change_inserted 0 1291205358
a1848 21
a1890 21
\change_unchanged
\end_layout
......@@ -3062,8 +3103,8 @@ reshuffling the free lists is trivial: we simply merge every consecutive
pair of free lists.
\change_unchanged
d1857 1
a1857 7
d1899 1
a1899 7
Identify the correct
\change_inserted 0 1291205366
free list
......@@ -3071,8 +3112,8 @@ free list
zone
\change_unchanged
.
d1865 2
a1866 7
d1907 2
a1908 7
Re-check the
\change_inserted 0 1291205372
list
......@@ -3080,15 +3121,15 @@ list
zone
\change_unchanged
(we didn't have a lock, sizes could have changed): relock if necessary.
d1870 1
a1870 5
d1912 1
a1912 5
Place the freed entry in the list
\change_deleted 0 1291205382
for that zone
\change_unchanged
.
d1879 1
a1879 15
d1921 1
a1921 15
Pick a
\change_deleted 0 1291205403
zone either the zone we last freed into, or based on a
......@@ -3104,7 +3145,7 @@ random
free table; usually the previous one.
\change_unchanged
a1883 10
a1925 10
\change_deleted 0 1291205432
\end_layout
......@@ -3115,8 +3156,8 @@ a1883 10
Re-check the zone: relock if necessary.
\change_unchanged
d1892 1
a1892 7
d1934 1
a1934 7
unlock the list and try the next
\change_inserted 0 1291205455
largest list
......@@ -3124,19 +3165,19 @@ largest list
zone.
\change_inserted 0 1291205457
a1895 2
a1937 2
\change_inserted 0 1291205476
a1896 2
a1938 2
\change_unchanged
a1924 2
a1966 2
\change_inserted 0 1291205542
a1927 2
a1969 2
\change_inserted 0 1291205591
a1929 70
a1971 70
\change_unchanged
\end_layout
......@@ -3207,20 +3248,20 @@ means 0 gives a minimal 65536-byte zone, 15 gives the maximal
\change_inserted 0 1291205139
d2176 1
a2176 5
d2218 1
a2218 5
uint32_t
\change_inserted 0 1291205758
used_
\change_unchanged
magic : 16,
a2180 4
a2222 4
\change_deleted 0 1291205693
prev_is_free: 1,
\change_unchanged
d2188 1
a2188 7
d2230 1
a2230 7
top_hash: 1
\change_inserted 0 1291205704
1
......@@ -3228,8 +3269,8 @@ a2188 7
0
\change_unchanged
;
d2212 1
a2212 9
d2254 1
a2254 9
uint
\change_inserted 0 1291205725
64
......@@ -3239,10 +3280,10 @@ a2212 9
_t
\change_inserted 0 1291205753
free_magic: 8,
a2215 2
a2257 2
\change_inserted 0 1291205746
a2220 24
a2262 24
\change_deleted 0 1291205749
free_magic;
\change_unchanged
......@@ -3267,8 +3308,8 @@ total_length
;
\change_unchanged
d2224 1
a2224 7
d2266 1
a2266 7
uint64_t
\change_deleted 0 1291205801
prev,
......@@ -3276,20 +3317,20 @@ prev,
next;
\change_deleted 0 1291205811
d2228 1
a2228 3
d2270 1
a2270 3
\change_deleted 0 1291205811
...
d2232 1
a2232 5
d2274 1
a2274 5
\change_deleted 0 1291205808
uint64_t tailer
\change_unchanged
;
d2241 5
a2245 16
d2283 5
a2287 16
\change_deleted 0 1291205827
We might want to take some bits from the used record's top_hash (and the
free record which has 32 bits of padding to spare anyway) if we use variable
......@@ -3306,90 +3347,90 @@ reference "freelist-in-zone"
\change_inserted 0 1291205885
Note that by limiting valid offsets to 56 bits, we can pack everything
we need into 3 64-byte words, meaning our minimum record size is 8 bytes.
a2248 2
a2290 2
\change_inserted 0 1291205886
a2252 2
a2294 2
\change_inserted 0 1291205886
a2253 2
a2295 2
\change_unchanged
a2343 2
a2385 2
\change_inserted 0 1291205894
a2346 2
a2388 2
\change_inserted 0 1291205894
a2350 2
a2392 2
\change_inserted 0 1291205902
a2351 2
a2393 2
\change_unchanged
a2373 4
a2415 4
\change_deleted 0 1291204504
\change_unchanged
a2403 2
a2445 2
\change_inserted 0 1291205910
a2406 2
a2448 2
\change_inserted 0 1291205910
a2410 2
a2452 2
\change_inserted 0 1291205914
a2411 2
a2453 2
\change_unchanged
a2443 2
a2485 2
\change_inserted 0 1291205919
a2446 2
a2488 2
\change_inserted 0 1291205919
a2450 2
a2492 2
\change_inserted 0 1291205922
a2451 2
a2493 2
\change_unchanged
a2491 2
a2533 2
\change_inserted 0 1291205929
a2494 2
a2536 2
\change_inserted 0 1291205929
a2498 2
a2540 2
\change_inserted 0 1291205929
a2499 2
a2541 2
\change_unchanged
a2536 2
a2578 2
\change_inserted 0 1291205932
a2539 2
a2581 2
\change_inserted 0 1291205933
a2543 2
a2585 2
\change_inserted 0 1291205933
a2544 2
a2586 2
\change_unchanged
a2682 2
a2724 2
\change_inserted 0 1291205944
a2685 2
a2727 2
\change_inserted 0 1291205945
a2689 2
a2731 2
\change_inserted 0 1291205948
a2690 2
a2732 2
\change_unchanged
@
......
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