ReadOnly
import type { ReadOnly } from "https://googleapis.deno.dev/v1/spanner:v1.ts";
Message type to initiate a read-only transaction.
§Properties
Executes all reads at a timestamp that is exact_staleness
old. The
timestamp is chosen soon after the read is started. Guarantees that all
writes that have committed more than the specified number of seconds ago
are visible. Because Cloud Spanner chooses the exact timestamp, this mode
works even if the client's local clock is substantially skewed from Cloud
Spanner commit timestamps. Useful for reading at nearby replicas without
the distributed timestamp negotiation overhead of max_staleness
.
Read data at a timestamp >= NOW - max_staleness
seconds. Guarantees that
all writes that have committed more than the specified number of seconds
ago are visible. Because Cloud Spanner chooses the exact timestamp, this
mode works even if the client's local clock is substantially skewed from
Cloud Spanner commit timestamps. Useful for reading the freshest data
available at a nearby replica, while bounding the possible staleness if the
local replica has fallen behind. Note that this option can only be used in
single-use transactions.
Executes all reads at a timestamp >= min_read_timestamp
. This is useful
for requesting fresher data than some previous read, or data that is fresh
enough to observe the effects of some previously committed transaction
whose timestamp is known. Note that this option can only be used in
single-use transactions. A timestamp in RFC3339 UTC "Zulu" format,
accurate to nanoseconds. Example: "2014-10-02T15:01:23.045123456Z"
.
Executes all reads at the given timestamp. Unlike other modes, reads at a
specific timestamp are repeatable; the same read at the same timestamp
always returns the same data. If the timestamp is in the future, the read
will block until the specified timestamp, modulo the read's deadline.
Useful for large scale consistent reads such as mapreduces, or for
coordinating many reads against a consistent snapshot of the data. A
timestamp in RFC3339 UTC "Zulu" format, accurate to nanoseconds. Example:
"2014-10-02T15:01:23.045123456Z"
.