polardbxengine/storage/innobase/trx/lizard0tcn.cc

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/** @file include/lizard0tcn.h
  Lizard transaction commit number cache

 Created 2021-11-05 by Jianwei.zhao
 *******************************************************/

#include "lizard0tcn.h"
#include "btr0pcur.h"
#include "buf0buf.h"
#include "lizard0iv.h"
#include "lizard0mon.h"
#include "lizard0row.h"
#include "lizard0undo0types.h"
#include "trx0trx.h"
#include "lizard0dbg.h"
#include "lizard0undo.h"

namespace lizard {

ulong innodb_tcn_cache_level = GLOBAL_LEVEL;
ulong innodb_tcn_block_cache_type = BLOCK_LRU;
bool innodb_tcn_cache_replace_after_commit = true;

Cache_tcn *global_tcn_cache = nullptr;

/** Search from tcn cache and overwrite the txn rec include
 * [UBA flag, scn, gcn]
 *
 * @param[in/out]	txn rec
 * @param[in]		pcur
 * @param[in/out]	txn lookup
 *
 * @retval		cache hit or not
 * */
bool trx_search_tcn(txn_rec_t *txn_rec, btr_pcur_t *pcur,
                    txn_lookup_t *txn_lookup) {
  tcn_t tcn;
  Cache_tcn *cont = nullptr;
  switch (innodb_tcn_cache_level) {
    case NONE_LEVEL:
      return false;
    case GLOBAL_LEVEL:
      cont = global_tcn_cache;
      break;
    case BLOCK_LEVEL:
      if (pcur) {
        cont = pcur->get_block()->cache_tcn;
      }
      break;
    default:
      ut_ad(0);
      cont = nullptr;
  }

  if (cont) {
    tcn = cont->search(txn_rec->trx_id);

    if (tcn.trx_id == txn_rec->trx_id) {
      lizard_undo_ptr_set_commit(&txn_rec->undo_ptr);
      txn_rec->scn = tcn.scn;
      txn_rec->gcn = tcn.gcn;

      ut_a(txn_rec->scn != SCN_NULL);
      ut_a(txn_rec->gcn != GCN_NULL);
      if (txn_lookup) {
        txn_lookup->real_image = {tcn.scn, UTC_UNDO_LOST, tcn.gcn};
        txn_lookup->real_state = TXN_STATE_COMMITTED;
      }

      TCN_CACHE_AGGR(innodb_tcn_cache_level, HIT);
      return true;
    }
  }
  TCN_CACHE_AGGR(innodb_tcn_cache_level, MISS);
  return false;
}

/** Cache */
void trx_cache_tcn(trx_id_t trx_id, txn_rec_t &txn_rec, const rec_t *rec,
                   const dict_index_t *index, const ulint *offsets,
                   btr_pcur_t *pcur) {
  Cache_tcn *cont = nullptr;
  ut_a(txn_rec.scn != SCN_NULL);
  ut_a(txn_rec.gcn != GCN_NULL);

  switch (innodb_tcn_cache_level) {
    case NONE_LEVEL:
      return;
    case GLOBAL_LEVEL:
      cont = global_tcn_cache;
      break;
    case BLOCK_LEVEL:
      tcn_collect(trx_id, txn_rec, rec, index, offsets, pcur);
      cont = nullptr;
      break;
    default:
      ut_ad(0);
      cont = nullptr;
  }
  if (cont) {
    tcn_t value(txn_rec);
    cont->insert(value);
    TCN_CACHE_AGGR(innodb_tcn_cache_level, EVICT);
  }
}

/** Cache the commit info into global tcn cache after commit. */
void trx_cache_tcn(trx_t *trx) {
  if (innodb_tcn_cache_replace_after_commit &&
      innodb_tcn_cache_level == GLOBAL_LEVEL && global_tcn_cache != nullptr) {
    commit_scn_t cmmt = trx->txn_desc.cmmt;
    trx_id_t trx_id = trx->id;

    if (trx_id != 0 && cmmt.scn != SCN_NULL && cmmt.gcn != GCN_NULL) {
      tcn_t value(trx_id, cmmt);
      global_tcn_cache->insert(value);
      TCN_CACHE_AGGR(innodb_tcn_cache_level, EVICT);
    }
  }
}

void allocate_block_tcn(buf_block_t *block) {
  if (block->cache_tcn == nullptr) {
    if (innodb_tcn_block_cache_type == BLOCK_LRU)
      block->cache_tcn = new Lru_tcn();
    else
      block->cache_tcn = new Array_tcn();
  }
}
void deallocate_block_tcn(buf_block_t *block) {
  if (block->cache_tcn != nullptr) {
    delete block->cache_tcn;
    block->cache_tcn = nullptr;
  }
}

}  // namespace lizard