---
task: Load item history from CSV (ithloahis) and read history back (dssqld)
version: R1.05 (first written for R1.03)
source: IM 36K10J10-01EN §2.9.2; IM 36K10L50-01EN §3.6 (5th ed., Feb. 2026); practiced with CI-Eng-Sample 2026-09-30 (R1.03)
status: verified on R1.03 (2026-09-30); on R1.05 `ithloahis` is installed but loading was not re-run (it writes history and the reduced CI-Eng-Sample load on the shared R1.05 test server has no storage group) - awaiting user verification
---

# Load item history (ithloahis) and read it back

**Writes to the history database.** Needs CI Server running and the items linked to an
item storage group of type *Event/Item* or *Event/Event*. The sample project provides
`CIENG_EVENT` with `CI-Eng-Sample.TANK1.LEVEL` and `.INFLOW`.

## Before loading

- A **new** storage group stores nothing until CI Server has been restarted (stop, then start
  the CI Service). Restart after creating a group.
- Samples are stored into the active unit **or an earlier unit opened by the storage process
  since the last restart** (e.g. one closed by a forced rollover). Samples older than the first
  unit opened after the restart are **dropped without any message**, even with `-l`, and even
  when an older unit's time range covers them (verified 2026-10-01, ISS-006). A restart closes
  the active unit and starts a new one, so load old data **before** restarting, or not at all.
  Check the unit times first: skill `history-management`, task `history-checks.md`.
- A dropped sample dated **shortly before** the first unit after the restart (same day) becomes
  the initial value of the next unit at the next rollover, instead of the item's live value
  (reproduced twice; a sample one day older did not do this, ISS-038). Check the result after
  loading, and do not load samples older than the active units.
- Loaded samples appear in `ITEM_HISTORY` a few seconds after `ithloahis` returns.

## Input files

Event file: one sample per line.

```
EVENT
<time>,<item>,<value>
1790739700,CI-Eng-Sample.TANK1.LEVEL,47
```

Scan file: several items per line (max 100), one line per timestamp.

```
SCAN,CI-Eng-Sample.TANK1.LEVEL,CI-Eng-Sample.TANK1.INFLOW
1790739715,61,101
1790739720,62,102
```

Time is seconds since 1970 (UTC), optionally with a fraction, or a date text such as
`29-Apr-14 11:48:17.452`. Quotes and spaces around fields are optional. A blank value in a
scan line is skipped.

## Load

```
ithloahis -f <file>.csv -v
```

- `-v` shows progress (`Handle event based table`, `item … on column n`).
- `-t GMT|LST|LCT` sets how text times are read (default GMT).
- `-s <section>` puts a section in front of every item name.
- `-i` also updates the item's current value (can raise alarms and trigger objects; loads the
  system). Without it, only history is written.

## Read history back

`ITEM_HISTORY` is not exported by default; use a filter file that names the item **and** a
time range, otherwise nothing is returned:

```
@SELECT
'ITEM_NAME = "CI-Eng-Sample.TANK1.LEVEL" and SAMPLE_TIME > "30-09-2026 00:00:00" and SAMPLE_TIME < "01-10-2026 00:00:00"'
@ITEM_HISTORY
```

```
dssqld -e history.qli <filter>.qli -c -l history.qlo
```

Result columns include `NAME` (`<group>:<item>/<time>/Value`), `SAMPLE_TIME`, `ITEM_VALUE`,
`QUALITY`. Values written live (e.g. with `itmval -p`) and the value at CI Server start also
appear.

## R1.05 check (awaiting user verification)

On a system where the CI-Eng-Sample storage group `CIENG_EVENT` exists (full sample load,
then a CI Server restart): load the SCAN example above with `ithloahis -f <file>.csv -v`, then
read it back with the `ITEM_HISTORY` filter. Expected as on R1.03: the three LEVEL / INFLOW
samples appear in `ITEM_HISTORY` a few seconds after the load. The manual text for `ithloahis` (J10 §2.9.2) is unchanged.

## Verified (CI-Eng-Sample, R1.03, 2026-09-30)

SCAN load of LEVEL 61–63 / INFLOW 101–103 and EVENT load of LEVEL 47, 48 were all read back
with the filter above.