# inno recover
Assess page-level recoverability and count salvageable records in an InnoDB tablespace.
## Synopsis
```text
inno recover -f <file> [-p <page>] [-v] [--json] [--force] [--page-size <size>] [--keyring <path>]
```
## Description
Scans a tablespace file and classifies each page into one of four states:
- **Intact**: Checksum is valid and LSN is consistent between header and trailer.
- **Corrupt**: Checksum mismatch or LSN inconsistency, but the FIL header is parseable.
- **Empty**: All-zero page (allocated but unused).
- **Unreadable**: Page data is too short or the FIL header cannot be parsed.
For INDEX pages, the compact record chain is walked to count recoverable user records. This gives a concrete estimate of how many rows can be salvaged from a damaged tablespace.
### Smart page size fallback
When page 0 is damaged and auto-detection fails, `inno recover` tries common page sizes (16K, 8K, 4K, 32K, 64K) in order, selecting the first one that divides evenly into the file size. Use `--page-size` to force a specific size when the heuristic is not sufficient.
### Force mode
By default, records are only counted on intact INDEX pages. With `--force`, records are also extracted from corrupt pages that have valid-looking FIL headers. This is useful when the checksum is damaged but the record chain is still intact, allowing more data to be recovered.
## Flags
| `--file <path>` | `-f` | Yes | -- | Path to the InnoDB data file (.ibd). |
| `--page <number>` | `-p` | No | All pages | Analyze a single page instead of a full scan. |
| `--verbose` | `-v` | No | Off | Show per-page details (type, status, LSN, record count). |
| `--json` | -- | No | Off | Output in JSON format. |
| `--force` | -- | No | Off | Extract records from corrupt pages with valid headers. |
| `--page-size <size>` | -- | No | Auto-detect (with fallback) | Override page size. Critical when page 0 is corrupt. |
| `--keyring <path>` | -- | No | -- | Path to MySQL keyring file for decrypting encrypted tablespaces. |
## Examples
### Quick recovery assessment
```bash
inno recover -f damaged_table.ibd
```
### Verbose per-page analysis
```bash
inno recover -f damaged_table.ibd -v
```
### Force-extract records from corrupt pages
```bash
inno recover -f damaged_table.ibd --force -v
```
### Analyze a single page
```bash
inno recover -f damaged_table.ibd -p 3 -v
```
### JSON output with per-page detail
```bash
inno recover -f damaged_table.ibd --json -v
```
### Override page size for a file with corrupt page 0
```bash
inno recover -f damaged_table.ibd --page-size 16384
```
## Output
### Text Mode
```text
Recovery Analysis: damaged_table.ibd
File size: 114688 bytes (7 pages x 16384 bytes)
Page size: 16384 (auto-detected)
Page Status Summary:
Intact: 5 pages
Corrupt: 1 pages (pages 3)
Empty: 1 pages
Unreadable: 0 pages
Total: 7 pages
Recoverable INDEX Pages: 3 of 4
Total user records: 200
Records on corrupt pages: 52 (use --force to include)
Overall: 83.3% of pages intact
```
With `--verbose`, per-page lines are displayed before the summary:
```text
Page 0: FSP_HDR intact LSN=1000
Page 1: IBUF_BITMAP intact LSN=1001
Page 2: INODE intact LSN=1002
Page 3: INDEX CORRUPT LSN=5000 records=52 checksum mismatch
Page 4: INDEX intact LSN=5001 records=100
Page 5: INDEX intact LSN=5002 records=100
Page 6: Allocated empty LSN=0
```
### JSON Mode
```json
{
"file": "damaged_table.ibd",
"file_size": 114688,
"page_size": 16384,
"total_pages": 7,
"summary": {
"intact": 5,
"corrupt": 1,
"empty": 1,
"unreadable": 0
},
"recoverable_records": 200,
"force_recoverable_records": 52,
"pages": []
}
```
With `--verbose`, the `pages` array includes per-page detail. When combined with `--verbose --json`, each INDEX page also includes per-record data with byte offsets, heap numbers, delete marks, and hex-encoded record bytes.