toastinfo
show details on toasted datums
Repository
credativ/toastinfo
https://github.com/credativ/toastinfo
Source
toastinfo-1.5.tar.gz
toastinfo-1.5.tar.gz
Overview
| Package | Version | Category | License | Language |
|---|---|---|---|---|
toastinfo | 1.5 | STAT | PostgreSQL | C |
| ID | Extension | Bin | Lib | Load | Create | Trust | Reloc | Schema |
|---|---|---|---|---|---|---|---|---|
| 6530 | toastinfo | No | Yes | No | Yes | No | Yes | - |
| Related | pageinspect pg_visibility pgstattuple amcheck pg_relusage pg_buffercache pg_freespacemap pg_repack |
|---|
Version
| Type | Repo | Version | PG Ver | Package | Deps |
|---|---|---|---|---|---|
| EXT | MIXED | 1.5 | 1817161514 | toastinfo | - |
| RPM | PIGSTY | 1.5 | 1817161514 | toastinfo_$v | - |
| DEB | PGDG | 1.5 | 1817161514 | postgresql-$v-toastinfo | - |
Build
You can build the RPM packages for toastinfo using pig build:
pig build pkg toastinfo # build RPM packages
Install
You can install toastinfo directly. First, make sure the PGDG and PIGSTY repositories are added and enabled:
pig repo add pgsql -u # Add repo and update cache
Install the extension using pig or apt/yum/dnf:
pig install toastinfo; # Install for current active PG version
pig ext install -y toastinfo -v 18 # PG 18
pig ext install -y toastinfo -v 17 # PG 17
pig ext install -y toastinfo -v 16 # PG 16
pig ext install -y toastinfo -v 15 # PG 15
pig ext install -y toastinfo -v 14 # PG 14
dnf install -y toastinfo_18 # PG 18
dnf install -y toastinfo_17 # PG 17
dnf install -y toastinfo_16 # PG 16
dnf install -y toastinfo_15 # PG 15
dnf install -y toastinfo_14 # PG 14
apt install -y postgresql-18-toastinfo # PG 18
apt install -y postgresql-17-toastinfo # PG 17
apt install -y postgresql-16-toastinfo # PG 16
apt install -y postgresql-15-toastinfo # PG 15
apt install -y postgresql-14-toastinfo # PG 14
Create Extension:
CREATE EXTENSION toastinfo;
Usage
toastinfo exposes the internal storage form of variable-length (varlena) data types, showing how PostgreSQL stores each datum.
Functions
pg_toastinfo(anyelement) – describes the storage form of a datum:
SELECT a, length(b), pg_column_size(b), pg_toastinfo(b), pg_toastpointer(b)
FROM t;
a | length | pg_column_size | pg_toastinfo | pg_toastpointer
------------------+---------+----------------+----------------------------------------+-----------------
null | * | * | null | *
default | 7 | 8 | short inline varlena | *
external-200 | 200 | 204 | long inline varlena, uncompressed | *
external-10000 | 10000 | 10000 | toasted varlena, uncompressed | 16427
extended-10000 | 10000 | 125 | long inline varlena, compressed (pglz) | *
extended-1000000 | 1000000 | 11452 | toasted varlena, compressed (pglz) | 16429
extended-1000000 | 1000000 | 3936 | toasted varlena, compressed (lz4) | 16430
Possible storage forms:
null– NULL valuesordinary– non-varlena datatypesshort inline varlena– up to 126 bytes (1-byte header)long inline varlena, (un)compressed– up to 1GiB (4-byte header)toasted varlena, (un)compressed– up to 1GiB stored in TOAST table- Compressed varlenas show method (
pglz,lz4) on PG14+
pg_toastpointer(anyelement) – returns the chunk_id OID in the TOAST table, or NULL for non-toasted data:
SELECT pg_toastpointer(large_column) FROM my_table;
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