--- title: "asinh" slug: "dev-database-reference-sql-functions-numeric-asinh" updated: 2026-10-30T18:18:51Z published: 2026-10-30T18:18:51Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-numeric-asinh" --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.vastdata.com/llms.txt > Use this file to discover all available pages before exploring further. # asinh *Applies to VAST Cluster 5.5.* *[Functions](/develop/docs/dev-database-reference-sql-functions-index) › [Numeric and math functions](/develop/docs/dev-database-reference-sql-functions-numeric) › Hyperbolic functions.* Returns the inverse hyperbolic sine of a number: the value whose [sinh](/develop/docs/dev-database-reference-sql-functions-numeric-sinh) is that number. It takes any number. For large values it grows like a logarithm, but unlike [ln](/develop/docs/dev-database-reference-sql-functions-numeric-ln) it's defined for zero and negative values, so it's a common way to compress a signed quantity onto a smaller scale. ## Syntax ``` asinh(x) ``` | Argument | Type | Description | | --- | --- | --- | | `x` | Any number (`DOUBLE`, `REAL`, an integer or a `DECIMAL`) | Any value, including `inf` and `-inf`. | **Returns:** `DOUBLE`. ## Set up the examples The examples connect with the ADBC driver, as in [VAST Query Engine (ADBC)](/develop/docs/dev-database-integrations-adbc), and work in a schema called `docs_sql_fn_numeric_asinh`. Set `QE_ENDPOINT`, `AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY` and `VASTDB_BUCKET` ([SQL reference](/develop/docs/dev-database-reference-sql-index#example-connect-and-use-a-transaction)), and run the blocks in order in one Python session. Below each block is the output you should see. This block connects, defines the `run()` and `plan()` helpers, and creates a table of six account balance changes, some negative. Row 3 has no value: ``` import os import re import adbc_driver_manager import adbc_driver_manager.dbapi as dbapi import adbc_driver_vastdb BUCKET = os.environ["VASTDB_BUCKET"] SCHEMA = f'"{BUCKET}/docs_sql_fn_numeric_asinh"' conn = dbapi.connect( driver=adbc_driver_vastdb.get_driver_path(), db_kwargs={ "vast.db.endpoint": os.environ["QE_ENDPOINT"], "vast.db.access_key": os.environ["AWS_ACCESS_KEY_ID"], "vast.db.secret_key": os.environ["AWS_SECRET_ACCESS_KEY"], }, autocommit=True, ) def server_message(e): """The server's message in a driver error, without the request ID or the echoed statement.""" text = re.sub(r"\[req=0x[0-9a-f]+\]: ", "", str(e)) found = (re.search(r'message: "(.*?)", request_id', text, re.S) or re.search(r"description: (.*)\)", text, re.S)) message = found.group(1) if found else text.strip().splitlines()[-1] message = re.sub(r"^Plan query: '.*?' failed with: ", "", message, flags=re.S) message = re.split(r"\\n|\n", message)[0].replace('\\"', '"') return message.replace(BUCKET, "") def run(sql): """Run one statement. Print the rows it returns, or the error.""" try: with conn.cursor() as cur: cur.execute(sql) rows = cur.fetchall() if cur.description else [] except (adbc_driver_manager.Error, OSError) as e: print(f"{type(e).__name__}: {server_message(e)}") else: print(rows) def plan(sql): """Print the plan without its ~N Rows lines: the table's row count, which can still be 0 just after an insert.""" with conn.cursor() as cur: cur.execute("EXPLAIN " + sql) steps = cur.fetchall()[0][1] print("\n".join(line for line in steps.splitlines() if "Rows" not in line)) TABLE = f"{SCHEMA}.changes" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, amount DOUBLE)") run(f"INSERT INTO {TABLE} VALUES " "(1, 1.0), (2, -1.0), (3, NULL), (4, 0.0), (5, 1000.0), (6, -1000000.0)") ``` ``` [] [] [(6,)] ``` ## What it does `asinh(x)` is the inverse of [sinh](/develop/docs/dev-database-reference-sql-functions-numeric-sinh): it returns the value `y` for which `sinh(y) = x`. It's an odd function (`asinh(-x)` is `-asinh(x)`) and it's 0 at 0. Near 0 it's close to `x`; for large `x` it grows like `ln(2x)`, so a value as large as `1e308` gives a result of only about 710. | Call | Result | | --- | --- | | `asinh(0)` | `0.0` | | `asinh(1)` | `0.881373587019543` | | `asinh(-1)` | `-0.881373587019543` | | `asinh(1e308)` | `709.889355822726` | | `asinh(-1e308)` | `-709.889355822726` | The result is a `DOUBLE` for every numeric argument type: an integer, a `REAL`, a `DECIMAL` or a `DOUBLE`. ``` run("SELECT asinh(0), asinh(1), asinh(-1), asinh(1e308), asinh(-1e308)") run("SELECT typeof(asinh(1::INTEGER)), typeof(asinh(0.5::FLOAT)), typeof(asinh(0.5))") ``` ``` [(0.0, 0.881373587019543, -0.881373587019543, 709.889355822726, -709.889355822726)] [('DOUBLE', 'DOUBLE', 'DOUBLE')] ``` ## NULLs and edge cases | Input | Result | | --- | --- | | `NULL` | `NULL` | | `'inf'::DOUBLE` | `inf` | | `'-inf'::DOUBLE` | `-inf` | | `'nan'::DOUBLE` | `nan` | | `-0.0::DOUBLE` | `-0.0`: the sign of zero is kept | | The smallest positive `DOUBLE` (`5e-324`) | `5e-324` | | `'12'` (a string literal holding a number) | Converted to `DOUBLE`: `3.179785437699879` | | `'abc'` (a string that isn't a number) | Error: `Could not convert string 'abc' to DOUBLE` | | A `BLOB`, date, boolean, list or interval | Error: `No function matches the given name and argument types`, for example `'asinh(DATE)'` | The same cases, as the cluster returns them. They use the helpers from [Set up the examples](/develop/docs/dev-database-reference-sql-functions-numeric-asinh#set-up-the-examples): ``` run("SELECT asinh(NULL), asinh('inf'::DOUBLE), asinh('-inf'::DOUBLE), asinh('nan'::DOUBLE)") run("SELECT asinh(-0.0::DOUBLE), asinh(5e-324::DOUBLE), asinh('12')") run("SELECT asinh('abc')") run("SELECT asinh(DATE '2026-10-16')") ``` ``` [(None, inf, -inf, nan)] [(-0.0, 5e-324, 3.179785437699879)] OSError: Could not convert string 'abc' to DOUBLE InternalError: Binder Error: No function matches the given name and argument types 'asinh(DATE)'. You might need to add explicit type casts. ``` ## Examples Each change on the `asinh` scale. Changes from -1,000,000 to 1,000 end up within about -15 to 8, with the sign kept and zero at zero: ``` run(f"SELECT id, amount, asinh(amount) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, 1.0, 0.881373587019543), (2, -1.0, -0.881373587019543), (3, None, None), (4, 0.0, 0.0), (5, 1000.0, 7.600902709541988), (6, -1000000.0, -14.50865773852447)] ``` Keep only the rows above 5 on that scale: ``` run(f"SELECT id, amount FROM {TABLE} WHERE asinh(amount) > 5 ORDER BY id LIMIT 10") ``` ``` [(5, 1000.0)] ``` ## How it runs in VAST The Query Engine runs on the cluster's CNodes, and a query on a table starts with a scan in VAST DataBase (`VAST_SCAN`). VAST DataBase can evaluate a comparison of a column with a constant, but not a function of a column, so `asinh()` is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `asinh()` for each row it returns. - **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `asinh()` and keeps the rows that match. No rows are skipped in storage. The plan of the `WHERE` example shows the `FILTER` step above the scan: ``` plan(f"SELECT id FROM {TABLE} WHERE asinh(amount) > 5") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #1 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ (asinh(amount) > 5.0) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ amount │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Compare the raw column with the inverse of the constant.** `asinh()` grows as its argument grows, so `asinh(amount) > 5` is the same condition as `amount > sinh(5)`. A function on constants is computed once, before the scan, so the second form is a comparison of the column with a constant, which is pushed down to VAST DataBase. Its plan has no `FILTER` step: ``` plan(f"SELECT id FROM {TABLE} WHERE amount > sinh(5)") run(f"SELECT id, amount FROM {TABLE} WHERE amount > sinh(5) ORDER BY id LIMIT 10") ``` ``` ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ [(5, 1000.0)] ``` - **Store the result if you filter on it often.** Compute it when you write the rows and keep it in its own column: a condition on that column is pushed down, a condition on `asinh()` isn't. ## Limitations and errors - **Numbers only.** A `BLOB`, a date, a boolean, a list or an interval fails with `No function matches the given name and argument types`; the error lists the one form `asinh` has, `asinh(DOUBLE) -> DOUBLE`. A string literal is converted to `DOUBLE` if it holds a number, and otherwise fails with `Could not convert string 'abc' to DOUBLE`. - **One argument.** `asinh(1, 2)` fails with `No function matches the given name and argument types 'asinh(INTEGER_LITERAL, INTEGER_LITERAL)'`. ## Similar functions | Function | Returns | For `0` and `-1` | | --- | --- | --- | | `asinh(x)` | the inverse hyperbolic sine, for any number | `0.0` and `-0.881373587019543` | | [ln](/develop/docs/dev-database-reference-sql-functions-numeric-ln) | the natural logarithm, for positive numbers only | Error: `cannot take logarithm of zero`; `cannot take logarithm of a negative number` | | [sinh](/develop/docs/dev-database-reference-sql-functions-numeric-sinh) | the hyperbolic sine: the inverse of `asinh` | `asinh(sinh(1))` is `1.0` | | [acosh](/develop/docs/dev-database-reference-sql-functions-numeric-acosh) | the inverse hyperbolic cosine, for 1 or more | | | [atanh](/develop/docs/dev-database-reference-sql-functions-numeric-atanh) | the inverse hyperbolic tangent, for -1 to 1 | | | [asin](/develop/docs/dev-database-reference-sql-functions-numeric-asin) | the inverse sine, an angle, for -1 to 1 | | ``` run("SELECT asinh(0), asinh(-1), asinh(sinh(1)), asinh(0.5), asin(0.5)") run("SELECT ln(0)") run("SELECT ln(-1)") ``` ``` [(0.0, -0.881373587019543, 1.0, 0.48121182505960347, 0.5235987755982989)] OSError: cannot take logarithm of zero OSError: cannot take logarithm of a negative number ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [Numeric and math functions](/develop/docs/dev-database-reference-sql-functions-numeric): all the numeric functions. - [Where filters run](/develop/docs/dev-database-reference-sql-select#where-filters-run) and [pushdowns](/develop/docs/dev-database-reference-pushdowns). - [EXPLAIN](/develop/docs/dev-database-reference-sql-explain): how to read a plan.