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- Fix a couple of edge cases while switching between collections.
  - Raise error if attempting to switch collections mid-transaction.
  - Add logic for re-entrancy with long-running transactions.
  - Revert to the prior collection if passing a block to #collection.
  - Add a predicate to tell if you're currently within a long-running transaction.
  - Add separate commit/rollback to long-running transactions.

FossilOrigin-Name: 711239e6fc2f25479a26fb54805da1e5db792f97f28a8b5724e0b38eb11cdb07
This commit is contained in:
Mahlon E. Smith 2021-01-25 00:36:40 +00:00
parent ceb92fad16
commit 81ee69295c
7 changed files with 239 additions and 29 deletions
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142
ext/mdbx_ext/database.c
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@ -47,6 +47,20 @@ rmdbx_close_all( rmdbx_db_t *db )
}
/*
* Close any open database handle. Will be automatically
* re-opened on next transaction. This is primarily useful for
* switching between subdatabases.
*/
void
rmdbx_close_dbi( rmdbx_db_t *db )
{
if ( ! db->dbi ) return;
mdbx_dbi_close( db->env, db->dbi );
db->dbi = 0;
}
/*
* Cleanup a previously allocated DB environment.
*/
@ -86,6 +100,21 @@ rmdbx_closed_p( VALUE self )
}
/*
* call-seq:
* db.in_transaction? #=> false
*
* Predicate: return true if a transaction (or snapshot)
* is currently open.
*/
VALUE
rmdbx_in_transaction_p( VALUE self )
{
UNWRAP_DB( self, db );
return db->txn ? Qtrue : Qfalse;
}
/*
* Open the DB environment handle.
*/
@ -156,17 +185,15 @@ rmdbx_open_txn( rmdbx_db_t *db, int rwflag )
/*
* Close any existing database transaction. If there is no
* active transaction, this is a no-op.
*
* FIXME: this needs a conditional no-op for long running
* transactions, so callers don't have to care/check
* active transaction, this is a no-op. If there is a long
* running transaction open, this is a no-op.
*
* +txnflag must either be RMDBX_TXN_ROLLBACK or RMDBX_TXN_COMMIT.
*/
void
rmdbx_close_txn( rmdbx_db_t *db, int txnflag )
{
if ( ! db->txn ) return;
if ( ! db->txn || db->state.retain_txn > -1 ) return;
switch ( txnflag ) {
case RMDBX_TXN_COMMIT:
@ -180,6 +207,46 @@ rmdbx_close_txn( rmdbx_db_t *db, int txnflag )
}
/*
* call-seq:
* db.open_transaction( mode )
*
* Open a new long-running transaction. If +mode+ is true,
* it is opened read/write.
*
*/
VALUE
rmdbx_rb_opentxn( VALUE self, VALUE mode )
{
UNWRAP_DB( self, db );
rmdbx_open_txn( db, RTEST(mode) ? MDBX_TXN_READWRITE : MDBX_TXN_RDONLY );
db->state.retain_txn = RTEST(mode) ? 1 : 0;
return Qtrue;
}
/*
* call-seq:
* db.close_transaction( mode )
*
* Close a long-running transaction. If +write+ is true,
* the transaction is committed. Otherwise, rolled back.
*
*/
VALUE
rmdbx_rb_closetxn( VALUE self, VALUE write )
{
UNWRAP_DB( self, db );
db->state.retain_txn = -1;
rmdbx_close_txn( db, RTEST(write) ? RMDBX_TXN_COMMIT : RMDBX_TXN_ROLLBACK );
return Qtrue;
}
/*
* call-seq:
* db.clear
@ -382,39 +449,63 @@ rmdbx_stats( VALUE self )
/*
* call-seq:
* Gets or sets the sub-database "collection" that read/write operations apply to.
* Passing +nil+ sets the database to the main, top-level namespace.
* If a block is passed, the collection automatically reverts to the
* prior collection when it exits.
*
* db.collection( 'collection_name' ) # => db
* db.collection( nil ) # => db (main)
*
* Operate on a sub-database "collection". Passing +nil+
* sets the database to the main, top-level namespace.
* db.collection( 'collection_name' ) do
* [ ... ]
* end #=> reverts to the previous collection name
*
*/
VALUE
rmdbx_set_subdb( int argc, VALUE *argv, VALUE self )
{
UNWRAP_DB( self, db );
VALUE subdb;
VALUE subdb, block;
char *prev_db = NULL;
rb_scan_args( argc, argv, "01", &subdb );
rb_scan_args( argc, argv, "01&", &subdb, &block );
if ( argc == 0 ) {
if ( db->subdb == NULL ) return Qnil;
return rb_str_new_cstr( db->subdb );
}
/* All transactions must be closed when switching database handles. */
if ( db->txn ) rb_raise( rmdbx_eDatabaseError, "Unable to change collection: finish current transaction" );
/* Retain the prior database collection if a
* block was passed. */
if ( rb_block_given_p() ) {
if ( db->subdb != NULL ) {
prev_db = (char *) malloc( strlen(db->subdb) + 1 );
strcpy( prev_db, db->subdb );
}
}
rb_iv_set( self, "@collection", subdb );
db->subdb = NIL_P( subdb ) ? NULL : StringValueCStr( subdb );
rmdbx_close_dbi( db );
/* Close any currently open dbi handle, to be re-opened with
* the new collection on next access.
*
/*
FIXME: Immediate transaction write to auto-create new env?
Fetching from here at the moment causes an error if you
haven't written anything yet.
haven't written anything to the new collection yet.
*/
if ( db->dbi ) {
mdbx_dbi_close( db->env, db->dbi );
db->dbi = 0;
/* Revert to the previous collection after the block is done. */
if ( rb_block_given_p() ) {
rb_yield( self );
if ( db->subdb != prev_db ) {
rb_iv_set( self, "@collection", prev_db ? rb_str_new_cstr(prev_db) : Qnil );
db->subdb = prev_db;
rmdbx_close_dbi( db );
}
free( prev_db );
}
return self;
@ -422,15 +513,14 @@ rmdbx_set_subdb( int argc, VALUE *argv, VALUE self )
/*
* call-seq:
* Open an existing (or create a new) mdbx database at filesystem
* +path+. In block form, the database is automatically closed.
*
* MDBX::Database.open( path ) -> db
* MDBX::Database.open( path, options ) -> db
* MDBX::Database.open( path, options ) do |db|
* db...
* end
*
* Open an existing (or create a new) mdbx database at filesystem
* +path+. In block form, the database is automatically closed.
* end
*
*/
VALUE
@ -458,7 +548,8 @@ rmdbx_database_initialize( int argc, VALUE *argv, VALUE self )
db->cursor = NULL;
db->path = StringValueCStr( path );
db->subdb = NULL;
db->state.open = 0;
db->state.open = 0;
db->state.retain_txn = -1;
db->settings.env_flags = MDBX_ENV_DEFAULTS;
db->settings.mode = 0644;
db->settings.max_collections = 0;
@ -530,11 +621,16 @@ rmdbx_init_database()
rb_define_method( rmdbx_cDatabase, "close", rmdbx_close, 0 );
rb_define_method( rmdbx_cDatabase, "reopen", rmdbx_open_env, 0 );
rb_define_method( rmdbx_cDatabase, "closed?", rmdbx_closed_p, 0 );
rb_define_method( rmdbx_cDatabase, "in_transaction?", rmdbx_in_transaction_p, 0 );
rb_define_method( rmdbx_cDatabase, "clear", rmdbx_clear, 0 );
rb_define_method( rmdbx_cDatabase, "keys", rmdbx_keys, 0 );
rb_define_method( rmdbx_cDatabase, "[]", rmdbx_get_val, 1 );
rb_define_method( rmdbx_cDatabase, "[]=", rmdbx_put_val, 2 );
/* Manually open/close transactions from ruby. */
rb_define_protected_method( rmdbx_cDatabase, "open_transaction", rmdbx_rb_opentxn, 1 );
rb_define_protected_method( rmdbx_cDatabase, "close_transaction", rmdbx_rb_closetxn, 1 );
rb_define_protected_method( rmdbx_cDatabase, "raw_stats", rmdbx_stats, 0 );
rb_require( "mdbx/database" );