Fixes cockroachdb#28666.
First commit from cockroachdb#41788.

This commit adds a `WITH diff` option to CREATE CHANGEFEED. When the
option is provided, changefeeds publications will include a `before`
field, which includes the value of the row before the CDC update was
applied.

We are able to implement this efficiently by pushing the option into
Rangefeed and performing the scan of the previous value immediately
before applying the update in the Raft processing goroutine. cockroachdb#41788
allows us to avoid performing this lookup when `WITH diff` isn't
specified for Rangefeeds, so the small (unmeasured) perf hit is
strictly opt-in.

DNM: this still needs testing and a bit of polish. It's also not clear
how we want to handle catch-up scans when the option is provided.

Fixes cockroachdb#28666.
First commit from cockroachdb#41788.

This commit adds a `WITH diff` option to CREATE CHANGEFEED. When the
option is provided, changefeeds publications will include a `before`
field, which includes the value of the row before the CDC update was
applied.

We are able to implement this efficiently by pushing the option into
Rangefeed and performing the scan of the previous value immediately
before applying the update in the Raft processing goroutine. cockroachdb#41788
allows us to avoid performing this lookup when `WITH diff` isn't
specified for Rangefeeds, so the small (unmeasured) perf hit is
strictly opt-in.

Release note (sql change): CHANGEFEED now supports a `WITH diff` option,
which instructs it to include a `before` field in each publication.

41788: storage/rangefeed: push rangefeed.Filter into Raft processing goroutine r=danhhz a=nvanbenschoten

This commit creates a `rangefeed.Filter` object, which informs the producer of logical operations of the information that a `rangefeed.Processor` is interested in, given its current set of registrations. It can be used to avoid performing extra work to provide the Processor with information which will be ignored.

This is an important optimization for single-key or small key span rangefeeds, as it avoids some extraneous work for the key spans not being watched.

For now, this extra work is just fetching the post-operation value for `MVCCWriteValueOp` and `MVCCCommitIntentOp` operations, but this can be extended in the future to include the pre-operation value as well. This will be important to avoid any perf regression when addressing #28666.

42580: sql: add precision support for TIMESTAMP/TIMESTAMPTZ (v2) r=otan a=otan

Refs #32098
Alternative to #42552

----

Add precision support for TIMESTAMP/TIMESTAMPTZ, supporting precisions
from 0 to 6 inclusive.

When storing this in the type proto, we introduce a `TimePrecisionIsSet`
variable, which is used to differentiate 0 (unset) or 0 (explicitly set)
for time related protos. This is abstracted away in the `Precision()`
function which returns the correct precision (unset => 6) for time. This
allows forwards and backwards compatibility.

Note Time will come later, as it involves a bit more plumbing to the
base library.

Release note (sql change): Introduces precision support for TIMESTAMP
and TIMESTAMPTZ, supporting precisions from 0 to 6 inclusive. Previous
versions of TIMESTAMP and TIMESTAMPTZ will default to 6 units of
precision. Note that if anyone downgrades whilst having precision set,
they will have full precision (6) again, but if they re-upgrade they
will find their precisions truncated again.

Co-authored-by: Nathan VanBenschoten <nvanbenschoten@gmail.com>
Co-authored-by: Oliver Tan <otan@cockroachlabs.com>

Fixes cockroachdb#28666.
First commit from cockroachdb#41788.

This commit adds a `WITH diff` option to CREATE CHANGEFEED. When the
option is provided, changefeeds publications will include a `before`
field, which includes the value of the row before the CDC update was
applied.

We are able to implement this efficiently by pushing the option into
Rangefeed and performing the scan of the previous value immediately
before applying the update in the Raft processing goroutine. cockroachdb#41788
allows us to avoid performing this lookup when `WITH diff` isn't
specified for Rangefeeds, so the small (unmeasured) perf hit is
strictly opt-in.

Release note (sql change): CHANGEFEED now supports a `WITH diff` option,
which instructs it to include a `before` field in each publication.

41793: ccl/changefeedccl: implement `WITH diff` option r=nvanbenschoten a=nvanbenschoten

Fixes #28666.

This commit adds a `WITH diff` option to CREATE CHANGEFEED. When the option is provided, changefeeds publications will include a `before` field, which includes the value of the row before the CDC update was applied.

We are able to implement this efficiently by pushing the option into Rangefeed and performing the scan of the previous value immediately before applying the update in the Raft processing goroutine. #41788 allows us to avoid performing this lookup when `WITH diff` isn't specified for Rangefeeds, so the small (unmeasured) perf hit is strictly opt-in.

Co-authored-by: Nathan VanBenschoten <nvanbenschoten@gmail.com>