ISAR/libmdbx
3
0
Fork 0
mirror of https://github.com/isar/libmdbx.git synced 2025-01-30 22:47:16 +08:00
Code Issues Packages Projects Releases Wiki Activity

mdbx: add MDBX_opt_spill_parent4child_denominator runtime option.

Browse Source 
More for https://github.com/erthink/libmdbx/issues/128

Change-Id: If1549c3855eb59c107eb115e6dbca515e81644f9
This commit is contained in:
Leonid Yuriev 2021-01-22 18:18:52 +03:00
parent 56aaad03bc
commit b82d1d5063
3 changed files with 42 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
mdbx.h
View File

@ -1917,6 +1917,29 @@ enum MDBX_option_t {
* bottom. Default is 8, i.e. at least the 1/8 of the current dirty pages
* should be spilled when reached the condition described above. */
MDBX_opt_spill_min_denominator,
/** \brief Controls the in-process how part of the parent transaction dirty
* pages will be spilled while start each child transaction.
*
* \details The `MDBX_opt_spill_parent4child_denominator` defines the
* denominator to determine how part of parent transaction dirty pages will be
* spilled explicitly while start each child transaction.
* Exactly `pages_to_spill = dirty_pages / N`,
* where `N` is the value set by `MDBX_opt_spill_parent4child_denominator`.
*
* For a stack of nested transactions each dirty page could be spilled only
* once, and parent's dirty pages couldn't be spilled while child
* transaction(s) are running. Therefore a child transaction could reach
* \ref MDBX_TXN_FULL when parent(s) transaction has spilled too less (and
* child reach the limit of dirty pages), either when parent(s) has spilled
* too more (since child can't spill already spilled pages). So there is no
* universal golden ratio.
*
* Should be in the range 0..255, where zero means no explicit spilling will
* be performed during starting nested transactions.
* Default is 0, i.e. by default no spilling performed during starting nested
* transactions, that correspond historically behaviour. */
MDBX_opt_spill_parent4child_denominator,
};
#ifndef __cplusplus
/** \ingroup c_settings */

18
src/core.c
View File

@ -6893,6 +6893,15 @@ int mdbx_txn_begin_ex(MDBX_env *env, MDBX_txn *parent, MDBX_txn_flags_t flags,
MDBX_TXN_RDONLY | MDBX_WRITEMAP | MDBX_TXN_BLOCKED);
if (unlikely(rc != MDBX_SUCCESS))
return rc;
if (env->me_options.spill_parent4child_denominator) {
/* Spill dirty-pages of parent to provide dirtyroom for child txn */
rc = mdbx_txn_spill(parent, nullptr,
parent->tw.dirtylist->length /
env->me_options.spill_parent4child_denominator);
if (unlikely(rc != MDBX_SUCCESS))
return rc;
}
mdbx_tassert(parent, mdbx_audit_ex(parent, 0, false) == 0);
flags |= parent->mt_flags & (MDBX_TXN_RW_BEGIN_FLAGS | MDBX_TXN_SPILLS);
@ -9922,6 +9931,7 @@ __cold int mdbx_env_create(MDBX_env **penv) {
env->me_options.dp_initial = env->me_options.dp_limit;
env->me_options.spill_max_denominator = 8;
env->me_options.spill_min_denominator = 8;
env->me_options.spill_parent4child_denominator = 0;
int rc;
const size_t os_psize = mdbx_syspagesize();
@ -20462,6 +20472,11 @@ __cold int mdbx_env_set_option(MDBX_env *env, const MDBX_option_t option,
return MDBX_EINVAL;
env->me_options.spill_min_denominator = (uint8_t)value;
break;
case MDBX_opt_spill_parent4child_denominator:
if (unlikely(value > 255))
return MDBX_EINVAL;
env->me_options.spill_parent4child_denominator = (uint8_t)value;
break;
default:
return MDBX_EINVAL;
@ -20522,6 +20537,9 @@ __cold int mdbx_env_get_option(const MDBX_env *env, const MDBX_option_t option,
case MDBX_opt_spill_min_denominator:
*value = env->me_options.spill_min_denominator;
break;
case MDBX_opt_spill_parent4child_denominator:
*value = env->me_options.spill_parent4child_denominator;
break;
default:
return MDBX_EINVAL;

1
src/internals.h
View File

@ -985,6 +985,7 @@ struct MDBX_env {
unsigned dp_initial;
uint8_t spill_max_denominator;
uint8_t spill_min_denominator;
uint8_t spill_parent4child_denominator;
} me_options;
struct {
#if MDBX_LOCKING > 0