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mdbx: refine mdbx_replace_ex().

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We can skip update only when a data exactly the same,
but user's md_dcmp() may returns zero even data is NOT matches byte-to-byte.
So to skip update the cmp_len fast() should be used instead of md_dcmp().

Change-Id: I6ad0f7cfc6a18722b46e565deef3a544ddf9968a
This commit is contained in:
Leonid Yuriev 2020-08-24 13:31:52 +03:00
parent 88a4b8cb9b
commit 08faeda430
1 changed files with 8 additions and 5 deletions
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13
src/core.c
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@ -18304,7 +18304,10 @@ int mdbx_replace_ex(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *key,
if (new_data) {
/* обновление конкретного дубликата */
if (cx.outer.mc_dbx->md_dcmp(old_data, new_data) == 0)
/* (!!!) We can skip update only when a data exactly the same, but user's
* md_dcmp() may returns zero even data is NOT matches byte-to-byte.
* So to skip update the cmp_len fast() should be used. */
if (cmp_lenfast(old_data, new_data) == 0)
/* если данные совпадают, то ничего делать не надо */
goto bailout;
}
@ -18338,8 +18341,8 @@ int mdbx_replace_ex(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *key,
}
}
/* если данные совпадают, то ничего делать не надо */
if (new_data &&
cx.outer.mc_dbx->md_dcmp(&present_data, new_data) == 0) {
if (new_data && /* the cmp_lenfast() must be used, see above */
cmp_lenfast(&present_data, new_data) == 0) {
*old_data = *new_data;
goto bailout;
}
@ -18355,8 +18358,8 @@ int mdbx_replace_ex(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *key,
}
} else {
/* если данные совпадают, то ничего делать не надо */
if (new_data &&
cx.outer.mc_dbx->md_dcmp(&present_data, new_data) == 0) {
if (new_data && /* the cmp_lenfast() must be used, see comment above */
cmp_lenfast(&present_data, new_data) == 0) {
*old_data = *new_data;
goto bailout;
}