From: Hallvard Furuseth Date: Thu, 20 Jun 2013 05:41:35 +0000 (+0200) Subject: ITS#7620: Keep empty IDLs. Tweak mdb_page_alloc(). X-Git-Tag: OPENLDAP_REL_ENG_2_4_36~36^2~14 X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=4a9ee2cb726fe8f5c4f256c1a567cdf6721c10a7;p=openldap ITS#7620: Keep empty IDLs. Tweak mdb_page_alloc(). MDB_env.me_pghead: Don't free it when empty. mdb_ovpage_free() needs it, but cannot allocate it. mdb_midl_alloc(): Fill in length=0. mdb_page_alloc(): Also Skip freeDB if txnid<3, instead of <4, and consistently DPRINTF consumed IDLs. --- diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index 3c8db7eefc..3a1d39ed84 100644 --- a/libraries/liblmdb/mdb.c +++ b/libraries/liblmdb/mdb.c @@ -928,8 +928,8 @@ typedef struct MDB_xcursor { /** State of FreeDB old pages, stored in the MDB_env */ typedef struct MDB_pgstate { - txnid_t mf_pglast; /**< ID of last old page record we used */ - pgno_t *mf_pghead; /**< old pages reclaimed from freelist */ + pgno_t *mf_pghead; /**< Reclaimed freeDB pages, or NULL before use */ + txnid_t mf_pglast; /**< ID of last used record, or 0 if !mf_pghead */ } MDB_pgstate; /** The database environment. */ @@ -1341,8 +1341,10 @@ static int mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp) { MDB_txn *txn = mc->mc_txn; + MDB_env *env = txn->mt_env; + pgno_t pgno = P_INVALID, *mop = env->me_pghead; + unsigned mop_len = mop ? mop[0] : 0; MDB_page *np; - pgno_t pgno = P_INVALID; MDB_ID2 mid; txnid_t oldest = 0, last; int rc; @@ -1353,13 +1355,11 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp) if (txn->mt_dirty_room == 0) return MDB_TXN_FULL; - /* The free list won't have any content at all until txn 2 has - * committed. The pages freed by txn 2 will be unreferenced - * after txn 3 commits, and so will be safe to re-use in txn 4. + /* Pages freed by txn#1 (after allocating but discarding them) + * are used when txn#1 is unreferenced, i.e. txn#3. */ - if (txn->mt_txnid > 3) { - if (!txn->mt_env->me_pghead && - txn->mt_dbs[FREE_DBI].md_root != P_INVALID) { + if (txn->mt_txnid >= 3) { + if (!mop_len && txn->mt_dbs[FREE_DBI].md_root != P_INVALID) { /* See if there's anything in the free DB */ MDB_cursor m2; MDB_node *leaf; @@ -1391,24 +1391,22 @@ again: if (oldest > last) { /* It's usable, grab it. */ - pgno_t *idl, *mop; + pgno_t *idl; if (!txn->mt_env->me_pglast) { mdb_node_read(txn, leaf, &data); } idl = (MDB_ID *) data.mv_data; - /* We might have a zero-length IDL due to freelist growth - * during a prior commit - */ - if (!idl[0]) { - txn->mt_env->me_pglast = last; - goto again; + mop_len = idl[0]; + if (!mop) { + if (!(env->me_pghead = mop = mdb_midl_alloc(mop_len))) + return ENOMEM; + } else if (mop_len > mop[-1]) { + if ((rc = mdb_midl_grow(&env->me_pghead, mop_len)) != 0) + return rc; + mop = env->me_pghead; } - mop = mdb_midl_alloc(idl[0]); - if (!mop) - return ENOMEM; txn->mt_env->me_pglast = last; - txn->mt_env->me_pghead = mop; memcpy(mop, idl, MDB_IDL_SIZEOF(idl)); #if MDB_DEBUG > 1 @@ -1420,11 +1418,15 @@ again: DPRINTF("IDL %zu", idl[i]); } #endif + /* We might have a zero-length IDL due to freelist growth + * during a prior commit + */ + if (!mop_len) + goto again; } } none: - if (txn->mt_env->me_pghead) { - pgno_t *mop = txn->mt_env->me_pghead; + if (mop_len) { if (num > 1) { MDB_cursor m2; int retry = 1, readit = 0, n2 = num-1; @@ -1448,7 +1450,7 @@ none: #endif if (readit) { MDB_val key, data; - pgno_t *idl, *mop2; + pgno_t *idl, old_id, new_id; last = txn->mt_env->me_pglast + 1; @@ -1473,22 +1475,31 @@ none: if (oldest <= last) break; idl = (MDB_ID *) data.mv_data; - mop2 = mdb_midl_alloc(idl[0] + mop[0]); - if (!mop2) - return ENOMEM; + i = idl[0]; + if (mop_len+i > mop[-1]) { + if ((rc = mdb_midl_grow(&env->me_pghead, i)) != 0) + return rc; + mop = env->me_pghead; + } +#if MDB_DEBUG > 1 + DPRINTF("IDL read txn %zu root %zu num %u", + last, txn->mt_dbs[FREE_DBI].md_root, i); + for (k = i; k; k--) + DPRINTF("IDL %zu", idl[k]); +#endif /* merge in sorted order */ - i = idl[0]; j = mop[0]; mop2[0] = k = i+j; + j = mop_len; + k = mop_len += i; mop[0] = P_INVALID; - while (i>0 || j>0) { - if (i && idl[i] < mop[j]) - mop2[k--] = idl[i--]; - else - mop2[k--] = mop[j--]; + old_id = mop[j]; + while (i) { + new_id = idl[i--]; + for (; old_id < new_id; old_id = mop[--j]) + mop[k--] = old_id; + mop[k--] = new_id; } + mop[0] = mop_len; txn->mt_env->me_pglast = last; - mdb_midl_free(txn->mt_env->me_pghead); - txn->mt_env->me_pghead = mop2; - mop = mop2; /* Keep trying to read until we have enough */ if (mop[0] < (unsigned)num) { continue; @@ -1519,10 +1530,6 @@ none: pgno = MDB_IDL_LAST(mop); mop[0]--; } - if (MDB_IDL_IS_ZERO(mop)) { - mdb_midl_free(txn->mt_env->me_pghead); - txn->mt_env->me_pghead = NULL; - } } } @@ -1966,7 +1973,6 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret) txn->mt_toggle = parent->mt_toggle; txn->mt_dirty_room = parent->mt_dirty_room; txn->mt_u.dirty_list[0].mid = 0; - txn->mt_free_pgs[0] = 0; txn->mt_next_pgno = parent->mt_next_pgno; parent->mt_child = txn; txn->mt_parent = parent; @@ -2138,7 +2144,7 @@ mdb_freelist_save(MDB_txn *txn) mdb_cursor_init(&mc, txn, FREE_DBI, NULL); - if (env->me_pghead || env->me_pglast) { + if (env->me_pghead) { /* Make sure first page of freeDB is touched and on freelist */ rc = mdb_page_search(&mc, NULL, MDB_PS_MODIFY); if (rc && rc != MDB_NOTFOUND) diff --git a/libraries/liblmdb/midl.c b/libraries/liblmdb/midl.c index d2617c61e4..00df385cdc 100644 --- a/libraries/liblmdb/midl.c +++ b/libraries/liblmdb/midl.c @@ -104,8 +104,10 @@ int mdb_midl_insert( MDB_IDL ids, MDB_ID id ) MDB_IDL mdb_midl_alloc(int num) { MDB_IDL ids = malloc((num+2) * sizeof(MDB_ID)); - if (ids) + if (ids) { *ids++ = num; + *ids = 0; + } return ids; }