Search Toolkit Book for MDB_rxbody
The information we store in a single slot of the reader table. More...
Collaboration diagram for MDB_rxbody:
Public Attributes | |
| volatile txnid_t | mrb_txnid |
| Current Transaction ID when this transaction began, or (txnid_t)-1. More... | |
| volatile pid_t | mrb_pid |
| The process ID of the process owning this reader txn. More... | |
| volatile pthread_t | mrb_tid |
| The thread ID of the thread owning this txn. More... | |
Detailed Description
The information we store in a single slot of the reader table.
In addition to a transaction ID, we also record the process and thread ID that owns a slot, so that we can detect stale information, e.g. threads or processes that went away without cleaning up.
- Note
- We currently don't check for stale records. We simply re-init the table when we know that we're the only process opening the lock file.
Member Data Documentation
◆ mrb_pid
| volatile pid_t MDB_rxbody::mrb_pid |
◆ mrb_tid
| volatile pthread_t MDB_rxbody::mrb_tid |
◆ mrb_txnid
| volatile txnid_t MDB_rxbody::mrb_txnid |
Current Transaction ID when this transaction began, or (txnid_t)-1.
Multiple readers that start at the same time will probably have the same ID here. Again, it's not important to exclude them from anything; all we need to know is which version of the DB they started from so we can avoid overwriting any data used in that particular version.
The documentation for this struct was generated from the following file:
- src/util/lmdb/mdb.c
