> [!NOTE] ModifyTable > <table> > <tr> > <td width="25%"><img src="assets/ex_modifytable.png"></td> > <td>The execution node responsible for performing <code>INSERT</code>, <code>UPDATE</code>, or <code>DELETE</code> operations. It handles the physical modification of tuples in the heap, manages index updates, and triggers Write-Ahead Log (WAL) insertions to ensure durability.</td> > </tr> > </table> > > ```sql > -- An UPDATE operation > EXPLAIN (ANALYZE, COSTS, BUFFERS, VERBOSE) > UPDATE animals SET name = 'Renamed' WHERE id = 1; > ``` > > ```text > Update on public.animals (cost=1.29..9.30 rows=0 width=0) (actual time=1.813..1.813 rows=0 loops=1) > Buffers: shared hit=23 read=3 dirtied=5 > -> Index Scan using animals_pkey on public.animals (...) > ``` > > <table> > <tr> > <td rowspan="5" width="25%"><img src="assets/ex_insert.svg"></td> > <td><b>Performance</b></td><td>High overhead due to physical I/O (WAL writing, index updates, and heap modification). Update and Delete are MVCC-compliant, meaning they mark old tuples as dead and (for Update) write new ones.</td> > </tr> > <tr><td><b>Factors</b></td><td>Number of rows modified, existence of indexes (which must be updated), and foreign key triggers.</td></tr> > <tr><td><b>Cost</b></td><td><code>operation cost * number of rows</code></td></tr> > <tr><td><b>Operates on</b></td><td><a href="Structures/Tuple">Tuple</a></td></tr> > <tr><td><b>Workloads</b></td><td><a href="Workloads/IO/DataFile/DataFileWrite">IO: DataFileWrite</a>, <a href="Workloads/IO/DataFile/DataFileExtend">IO: DataFileExtend</a>, <a href="Workloads/IO/DataFile/DataFileSync">IO: DataFileSync</a>, <a href="Workloads/IO/WAL/WALWrite">IO: WALWrite</a>, <a href="Workloads/Lock/Lock/Lock_Relation">Lock: Relation</a>, <a href="Workloads/Lock/Lock/Lock_Tuple">Lock: Tuple</a>, <a href="Workloads/Lock/Lock/Lock_TransactionId">Lock: TransactionId</a>, <a href="Workloads/LWLock/WAL/WALInsert">LWLock: WALInsert</a>, <a href="Workloads/LWLock/Buffers/BufferContent">LWLock: BufferContent</a>, <a href="Workloads/LWLock/Buffers/BufferMapping">LWLock: BufferMapping</a>, <a href="Workloads/IPC/Replication/SyncRep">IPC: SyncRep</a></td></tr> > <tr><td colspan="3"><b>Description</b>: Handles insert, update, and delete operations.</td></tr> > </table>