session/

context.rs

// Copyright 2023 Greptime Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::collections::HashMap;
use std::fmt::{Display, Formatter};
use std::net::SocketAddr;
use std::str::FromStr;
use std::sync::{Arc, RwLock};
use std::time::Duration;

use api::v1::ExplainOptions;
use api::v1::region::RegionRequestHeader;
use arc_swap::ArcSwap;
use auth::UserInfoRef;
pub use common_base::protocol::Channel;
use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
use common_catalog::{build_db_string, parse_catalog_and_schema_from_db_string};
use common_recordbatch::cursor::RecordBatchStreamCursor;
use common_telemetry::warn;
use common_time::Timezone;
use common_time::timezone::parse_timezone;
use datafusion_common::config::ConfigOptions;
use derive_builder::Builder;
use sql::dialect::{Dialect, GenericDialect, GreptimeDbDialect, MySqlDialect, PostgreSqlDialect};

pub use crate::hints::{
    LIVE_ANALYZE_METRICS_EXTENSION_KEY, READ_PREFERENCE_EXTENSION_KEY,
    REMOTE_QUERY_ID_EXTENSION_KEY, SUPPORT_FLIGHT_METRICS_BEFORE_BATCH_EXTENSION_KEY,
};
use crate::protocol_ctx::ProtocolCtx;
use crate::query_id::QueryId;
use crate::session_config::{
    InvalidConfigValueSnafu, PGByteaOutputValue, PGDateOrder, PGDateTimeStyle, PGIntervalStyle,
};
use crate::{MutableInner, ReadPreference};

pub type QueryContextRef = Arc<QueryContext>;
pub type ConnInfoRef = Arc<ConnInfo>;

pub const FLIGHT_METRICS_HEARTBEAT_INTERVAL: Duration = Duration::from_secs(1);

const CURSOR_COUNT_WARNING_LIMIT: usize = 10;

pub fn generate_remote_query_id() -> String {
    generate_remote_query_id_value().to_string()
}

pub fn generate_remote_query_id_value() -> QueryId {
    QueryId::new()
}

#[derive(Debug, Builder, Clone)]
#[builder(pattern = "owned")]
#[builder(build_fn(skip))]
pub struct QueryContext {
    current_catalog: String,
    /// mapping of RegionId to SequenceNumber, for snapshot read, meaning that the read should only
    /// container data that was committed before(and include) the given sequence number
    snapshot_seqs: Arc<RwLock<HashMap<u64, u64>>>,
    /// Mappings of the RegionId to the minimal sequence of SST file to scan.
    sst_min_sequences: Arc<RwLock<HashMap<u64, u64>>>,
    // we use Arc<RwLock>> for modifiable fields
    #[builder(default)]
    mutable_session_data: Arc<RwLock<MutableInner>>,
    #[builder(default)]
    mutable_query_context_data: Arc<RwLock<QueryContextMutableFields>>,
    sql_dialect: Arc<dyn Dialect + Send + Sync>,
    #[builder(default)]
    extensions: HashMap<String, String>,
    #[builder(setter(skip))]
    query_options_snapshotted: bool,
    /// The configuration parameter are used to store the parameters that are set by the user
    #[builder(default)]
    configuration_parameter: Arc<ConfigurationVariables>,
    /// Local-only write batching selection; never transported in protobuf extensions.
    #[builder(default)]
    batching_enabled: bool,
    /// Local-only opt-in for logical metric writes, independent of ordinary-table batching.
    #[builder(default)]
    logical_batching_enabled: bool,
    /// Track which protocol the query comes from.
    #[builder(default)]
    channel: Channel,
    /// Process-local admission for one database in this request. Never sent over the wire.
    #[builder(setter(skip))]
    admitted_write: Option<(String, String)>,
    /// Process id for managing on-going queries
    #[builder(default)]
    process_id: u32,
    /// Connection information
    #[builder(default)]
    conn_info: ConnInfo,
    /// Protocol specific context
    #[builder(default)]
    protocol_ctx: ProtocolCtx,
}

/// This fields hold data that is only valid to current query context
#[derive(Debug, Builder, Clone, Default)]
pub struct QueryContextMutableFields {
    warning: Option<String>,
    // TODO: remove this when format is supported in datafusion
    explain_format: Option<String>,
    /// Explain options to control the verbose analyze output.
    explain_options: Option<ExplainOptions>,
}

impl Display for QueryContext {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "QueryContext{{catalog: {}, schema: {}}}",
            self.current_catalog(),
            self.current_schema()
        )
    }
}

impl QueryContextBuilder {
    pub fn current_schema(mut self, schema: String) -> Self {
        if self.mutable_session_data.is_none() {
            self.mutable_session_data = Some(Arc::new(RwLock::new(MutableInner::default())));
        }

        // safe for unwrap because previous none check
        self.mutable_session_data
            .as_mut()
            .unwrap()
            .write()
            .unwrap()
            .schema = schema;
        self
    }

    pub fn timezone(mut self, timezone: Timezone) -> Self {
        if self.mutable_session_data.is_none() {
            self.mutable_session_data = Some(Arc::new(RwLock::new(MutableInner::default())));
        }

        self.mutable_session_data
            .as_mut()
            .unwrap()
            .write()
            .unwrap()
            .timezone = timezone;
        self
    }

    pub fn explain_options(mut self, explain_options: Option<ExplainOptions>) -> Self {
        self.mutable_query_context_data
            .get_or_insert_default()
            .write()
            .unwrap()
            .explain_options = explain_options;
        self
    }

    pub fn skip_wal(mut self, skip_wal: bool) -> Self {
        self.mutable_session_data
            .get_or_insert_default()
            .write()
            .unwrap()
            .skip_wal = skip_wal;
        self
    }

    pub fn read_preference(mut self, read_preference: ReadPreference) -> Self {
        self.mutable_session_data
            .get_or_insert_default()
            .write()
            .unwrap()
            .read_preference = read_preference;
        self
    }
}

impl TryFrom<&RegionRequestHeader> for QueryContext {
    type Error = crate::session_config::Error;

    fn try_from(value: &RegionRequestHeader) -> Result<Self, Self::Error> {
        if let Some(ctx) = &value.query_context {
            ctx.clone().try_into()
        } else {
            Ok(QueryContextBuilder::default()
                .set_extension(
                    REMOTE_QUERY_ID_EXTENSION_KEY.to_string(),
                    generate_remote_query_id(),
                )
                .build())
        }
    }
}

impl TryFrom<api::v1::QueryContext> for QueryContext {
    type Error = crate::session_config::Error;

    fn try_from(mut ctx: api::v1::QueryContext) -> Result<Self, Self::Error> {
        let read_preference = ctx.extensions.remove(READ_PREFERENCE_EXTENSION_KEY);
        let read_preference = match read_preference {
            Some(value) => ReadPreference::from_str(&value).map_err(|_| {
                InvalidConfigValueSnafu {
                    name: "read_preference",
                    value,
                    hint: "Expected a supported read preference",
                }
                .build()
            })?,
            None => ReadPreference::default(),
        };
        let sequences = ctx.snapshot_seqs.as_ref();
        Ok(QueryContextBuilder::default()
            .current_catalog(ctx.current_catalog)
            .current_schema(ctx.current_schema)
            .timezone(parse_timezone(Some(&ctx.timezone)))
            .extensions(ctx.extensions)
            .channel(ctx.channel.into())
            .snapshot_seqs(Arc::new(RwLock::new(
                sequences
                    .map(|x| x.snapshot_seqs.clone())
                    .unwrap_or_default(),
            )))
            .sst_min_sequences(Arc::new(RwLock::new(
                sequences
                    .map(|x| x.sst_min_sequences.clone())
                    .unwrap_or_default(),
            )))
            .explain_options(ctx.explain)
            .read_preference(read_preference)
            .build())
    }
}

impl From<QueryContext> for api::v1::QueryContext {
    fn from(
        QueryContext {
            current_catalog,
            mutable_session_data: mutable_inner,
            extensions,
            channel,
            snapshot_seqs,
            sst_min_sequences,
            mutable_query_context_data,
            ..
        }: QueryContext,
    ) -> Self {
        let explain = mutable_query_context_data.read().unwrap().explain_options;
        let mutable_inner = mutable_inner.read().unwrap();
        let mut extensions = extensions;
        extensions.remove(READ_PREFERENCE_EXTENSION_KEY);
        if mutable_inner.read_preference != ReadPreference::Leader {
            extensions.insert(
                READ_PREFERENCE_EXTENSION_KEY.to_string(),
                mutable_inner
                    .read_preference
                    .to_string()
                    .to_ascii_lowercase(),
            );
        }
        api::v1::QueryContext {
            current_catalog,
            current_schema: mutable_inner.schema.clone(),
            timezone: mutable_inner.timezone.to_string(),
            extensions,
            channel: channel as u32,
            snapshot_seqs: Some(api::v1::SnapshotSequences {
                snapshot_seqs: snapshot_seqs.read().unwrap().clone(),
                sst_min_sequences: sst_min_sequences.read().unwrap().clone(),
            }),
            explain,
        }
    }
}

impl From<&QueryContext> for api::v1::QueryContext {
    fn from(ctx: &QueryContext) -> Self {
        ctx.clone().into()
    }
}

impl QueryContext {
    /// Forks this context with an independent snapshot of mutable session data.
    ///
    /// Unlike [`Clone`], changes to the schema, user, timezone, and other fields
    /// held in mutable session data do not affect this context.
    pub fn fork(&self) -> Self {
        let mut fork = self.clone();
        fork.mutable_session_data = Arc::new(RwLock::new(
            self.mutable_session_data.read().unwrap().clone(),
        ));
        fork
    }

    /// Forks a context for internal writes after admitting the complete request.
    /// Call only after write admission succeeds for the current database.
    pub fn with_write_admission(&self) -> Self {
        let mut ctx = self.fork();
        ctx.admitted_write = Some((ctx.current_catalog().to_string(), ctx.current_schema()));
        ctx
    }

    /// Returns zero for writes covered by this request's database admission.
    /// Usage accounting and the original protocol channel remain unchanged.
    pub fn write_rows_to_admit(&self, catalog: &str, schema: &str, rows: u64) -> u64 {
        if self
            .admitted_write
            .as_ref()
            .is_some_and(|(c, s)| c == catalog && s == schema)
        {
            0
        } else {
            rows
        }
    }

    pub fn arc() -> QueryContextRef {
        Arc::new(
            QueryContextBuilder::default()
                .set_extension(
                    REMOTE_QUERY_ID_EXTENSION_KEY.to_string(),
                    generate_remote_query_id(),
                )
                .build(),
        )
    }

    /// Create a new  datafusion's ConfigOptions instance based on the current QueryContext.
    pub fn create_config_options(&self) -> ConfigOptions {
        let mut config = ConfigOptions::default();
        config.execution.time_zone = Some(self.timezone().to_string());
        config
    }

    pub fn with(catalog: &str, schema: &str) -> QueryContext {
        QueryContextBuilder::default()
            .current_catalog(catalog.to_string())
            .current_schema(schema.to_string())
            .set_extension(
                REMOTE_QUERY_ID_EXTENSION_KEY.to_string(),
                generate_remote_query_id(),
            )
            .build()
    }

    pub fn with_channel(catalog: &str, schema: &str, channel: Channel) -> QueryContext {
        QueryContextBuilder::default()
            .current_catalog(catalog.to_string())
            .current_schema(schema.to_string())
            .channel(channel)
            .set_extension(
                REMOTE_QUERY_ID_EXTENSION_KEY.to_string(),
                generate_remote_query_id(),
            )
            .build()
    }

    pub fn with_db_name(db_name: Option<&str>) -> QueryContext {
        let (catalog, schema) = db_name
            .map(|db| {
                let (catalog, schema) = parse_catalog_and_schema_from_db_string(db);
                (catalog, schema)
            })
            .unwrap_or_else(|| {
                (
                    DEFAULT_CATALOG_NAME.to_string(),
                    DEFAULT_SCHEMA_NAME.to_string(),
                )
            });
        QueryContextBuilder::default()
            .current_catalog(catalog)
            .current_schema(schema.clone())
            .set_extension(
                REMOTE_QUERY_ID_EXTENSION_KEY.to_string(),
                generate_remote_query_id(),
            )
            .build()
    }

    pub fn current_schema(&self) -> String {
        self.mutable_session_data.read().unwrap().schema.clone()
    }

    pub fn set_current_schema(&self, new_schema: &str) {
        self.mutable_session_data.write().unwrap().schema = new_schema.to_string();
    }

    pub fn current_catalog(&self) -> &str {
        &self.current_catalog
    }

    pub fn set_current_catalog(&mut self, new_catalog: &str) {
        self.current_catalog = new_catalog.to_string();
    }

    pub fn sql_dialect(&self) -> &(dyn Dialect + Send + Sync) {
        &*self.sql_dialect
    }

    pub fn get_db_string(&self) -> String {
        let catalog = self.current_catalog();
        let schema = self.current_schema();
        build_db_string(catalog, &schema)
    }

    pub fn timezone(&self) -> Timezone {
        self.mutable_session_data.read().unwrap().timezone.clone()
    }

    pub fn set_timezone(&self, timezone: Timezone) {
        self.mutable_session_data.write().unwrap().timezone = timezone;
    }

    /// Returns whether ordinary inserts in this request should skip WAL.
    pub fn skip_wal(&self) -> bool {
        self.mutable_session_data.read().unwrap().skip_wal
    }

    pub fn set_skip_wal(&self, skip_wal: bool) {
        self.mutable_session_data.write().unwrap().skip_wal = skip_wal;
    }

    pub fn read_preference(&self) -> ReadPreference {
        self.mutable_session_data.read().unwrap().read_preference
    }

    pub fn set_read_preference(&self, read_preference: ReadPreference) {
        self.mutable_session_data.write().unwrap().read_preference = read_preference;
    }

    /// Returns the latest procedure ID recorded in this Session.
    pub fn last_procedure_id(&self) -> Option<String> {
        self.mutable_session_data
            .read()
            .unwrap()
            .last_procedure_id
            .clone()
    }

    /// Records a procedure ID after successful statement execution and
    /// construction of its ID result.
    ///
    /// Recording precedes `post_execute` hooks and protocol transmission, which
    /// may still fail. It does not confirm that the client received the ID.
    pub fn set_last_procedure_id(&self, procedure_id: String) {
        self.mutable_session_data.write().unwrap().last_procedure_id = Some(procedure_id);
    }

    pub fn current_user(&self) -> UserInfoRef {
        self.mutable_session_data.read().unwrap().user_info.clone()
    }

    pub fn set_current_user(&self, user: UserInfoRef) {
        self.mutable_session_data.write().unwrap().user_info = user;
    }

    pub fn set_extension<S1: Into<String>, S2: Into<String>>(&mut self, key: S1, value: S2) {
        self.extensions.insert(key.into(), value.into());
    }

    pub fn extension<S: AsRef<str>>(&self, key: S) -> Option<&str> {
        self.extensions.get(key.as_ref()).map(|v| v.as_str())
    }

    pub fn remote_query_id(&self) -> Option<&str> {
        self.extension(REMOTE_QUERY_ID_EXTENSION_KEY)
    }

    pub fn remote_query_id_value(&self) -> Option<QueryId> {
        self.remote_query_id()
            .and_then(|query_id| query_id.parse().ok())
    }

    pub fn enable_live_analyze_metrics(&mut self) {
        if let Some(remote_query_id) = self.remote_query_id().map(str::to_string) {
            self.set_extension(LIVE_ANALYZE_METRICS_EXTENSION_KEY, remote_query_id);
        }
    }

    pub fn live_analyze_metrics_enabled(&self) -> bool {
        self.remote_query_id()
            .zip(self.extension(LIVE_ANALYZE_METRICS_EXTENSION_KEY))
            .is_some_and(|(remote_query_id, value)| value == remote_query_id)
    }

    pub fn extensions(&self) -> HashMap<String, String> {
        self.extensions.clone()
    }

    /// Returns normalized query options from the request over session defaults.
    pub fn effective_query_options(
        &self,
    ) -> Result<HashMap<String, String>, crate::session_config::Error> {
        let mut request_options = HashMap::new();
        for (key, value) in &self.extensions {
            if crate::hints::is_reserved_extension_key(key) {
                continue;
            }
            // Older Frontends and Flownodes forward `query_parallelism=0` (their
            // "use the server default" encoding) untouched inside the wire
            // query context, so accept it as unset instead of failing the
            // query on the Datanode side. The canonical
            // `query.parallelism = 0` stays rejected.
            if key.eq_ignore_ascii_case("query_parallelism") && value == "0" {
                continue;
            }
            // Wire decoding preserves legacy frontend nonzero values; public entry points enforce the limit.
            if let Some((canonical, normalized)) =
                crate::query_options::parse_query_option(key, value, u16::MAX)?
            {
                if request_options
                    .get(&canonical)
                    .is_some_and(|previous| previous != &normalized)
                {
                    return crate::session_config::InvalidConfigValueSnafu {
                        name: key,
                        value,
                        hint: "Conflicting aliases for the same query option",
                    }
                    .fail();
                }
                request_options.insert(canonical, normalized);
            }
        }
        let mut effective = if self.query_options_snapshotted {
            HashMap::new()
        } else {
            self.configuration_parameter.query_options()
        };
        effective.extend(request_options);
        Ok(effective)
    }

    /// Creates a per-query immutable option snapshot while retaining shared mutable session data.
    pub fn query_option_snapshot(&self) -> Result<Self, crate::session_config::Error> {
        let mut snapshot = self.clone();
        let options = snapshot.effective_query_options()?;
        snapshot
            .extensions
            .retain(|key, _| crate::query_options::canonical_query_option_name(key).is_none());
        // Older Datanodes only understand the legacy `query_parallelism` hint key, so
        // mirror the canonical parallelism override for the wire format while keeping
        // the canonical key for in-process consumers.
        let legacy_parallelism = options
            .get("query.parallelism")
            .map(|parallelism| ("query_parallelism".to_string(), parallelism.clone()));
        snapshot.extensions.extend(options);
        if let Some((key, value)) = legacy_parallelism {
            snapshot.extensions.entry(key).or_insert(value);
        }
        snapshot.query_options_snapshotted = true;
        Ok(snapshot)
    }

    /// Default to double quote and fallback to back quote
    pub fn quote_style(&self) -> char {
        if self.sql_dialect().is_delimited_identifier_start('"') {
            '"'
        } else if self.sql_dialect().is_delimited_identifier_start('\'') {
            '\''
        } else {
            '`'
        }
    }

    pub fn configuration_parameter(&self) -> &ConfigurationVariables {
        &self.configuration_parameter
    }

    /// Whether the local HTTP entry point selected logical-table batching.
    pub fn logical_batching_enabled(&self) -> bool {
        self.logical_batching_enabled
    }

    /// Sets local logical-table batching selection without adding a wire-visible extension.
    pub fn set_logical_batching_enabled(&mut self, enabled: bool) {
        self.logical_batching_enabled = enabled;
    }

    /// Whether the local protocol entry point selected ordinary-table batching.
    pub fn batching_enabled(&self) -> bool {
        self.batching_enabled
    }

    /// Sets local write batching selection without adding a wire-visible extension.
    pub fn set_batching_enabled(&mut self, enabled: bool) {
        self.batching_enabled = enabled;
    }

    pub fn channel(&self) -> Channel {
        self.channel
    }

    pub fn set_channel(&mut self, channel: Channel) {
        self.channel = channel;
    }

    pub fn warning(&self) -> Option<String> {
        self.mutable_query_context_data
            .read()
            .unwrap()
            .warning
            .clone()
    }

    pub fn set_warning(&self, msg: String) {
        self.mutable_query_context_data.write().unwrap().warning = Some(msg);
    }

    pub fn explain_format(&self) -> Option<String> {
        self.mutable_query_context_data
            .read()
            .unwrap()
            .explain_format
            .clone()
    }

    pub fn set_explain_format(&self, format: String) {
        self.mutable_query_context_data
            .write()
            .unwrap()
            .explain_format = Some(format);
    }

    pub fn explain_verbose(&self) -> bool {
        self.mutable_query_context_data
            .read()
            .unwrap()
            .explain_options
            .map(|opts| opts.verbose)
            .unwrap_or(false)
    }

    pub fn set_explain_verbose(&self, verbose: bool) {
        self.mutable_query_context_data
            .write()
            .unwrap()
            .explain_options
            .get_or_insert_default()
            .verbose = verbose;
    }

    pub fn query_timeout(&self) -> Option<Duration> {
        self.mutable_session_data.read().unwrap().query_timeout
    }

    pub fn query_timeout_as_millis(&self) -> u128 {
        let timeout = self.mutable_session_data.read().unwrap().query_timeout;
        if let Some(t) = timeout {
            return t.as_millis();
        }
        0
    }

    pub fn set_query_timeout(&self, timeout: Duration) {
        self.mutable_session_data.write().unwrap().query_timeout = Some(timeout);
    }

    pub fn insert_cursor(&self, name: String, rb: RecordBatchStreamCursor) {
        let mut guard = self.mutable_session_data.write().unwrap();
        guard.cursors.insert(name, Arc::new(rb));

        let cursor_count = guard.cursors.len();
        if cursor_count > CURSOR_COUNT_WARNING_LIMIT {
            warn!("Current connection has {} open cursors", cursor_count);
        }
    }

    pub fn remove_cursor(&self, name: &str) {
        let mut guard = self.mutable_session_data.write().unwrap();
        guard.cursors.remove(name);
    }

    pub fn get_cursor(&self, name: &str) -> Option<Arc<RecordBatchStreamCursor>> {
        let guard = self.mutable_session_data.read().unwrap();
        let rb = guard.cursors.get(name);
        rb.cloned()
    }

    pub fn snapshots(&self) -> HashMap<u64, u64> {
        self.snapshot_seqs.read().unwrap().clone()
    }

    pub fn sst_min_sequences(&self) -> HashMap<u64, u64> {
        self.sst_min_sequences.read().unwrap().clone()
    }

    pub fn get_snapshot(&self, region_id: u64) -> Option<u64> {
        self.snapshot_seqs.read().unwrap().get(&region_id).cloned()
    }

    pub fn set_snapshot(&self, region_id: u64, sequence: u64) {
        self.snapshot_seqs
            .write()
            .unwrap()
            .insert(region_id, sequence);
    }

    /// Returns `true` if the session can cast strings to numbers in MySQL style.
    pub fn auto_string_to_numeric(&self) -> bool {
        matches!(self.channel, Channel::Mysql)
    }

    /// Finds the minimal sequence of SST files to scan of a Region.
    pub fn sst_min_sequence(&self, region_id: u64) -> Option<u64> {
        self.sst_min_sequences
            .read()
            .unwrap()
            .get(&region_id)
            .copied()
    }

    pub fn process_id(&self) -> u32 {
        self.process_id
    }

    /// Get client information
    pub fn conn_info(&self) -> &ConnInfo {
        &self.conn_info
    }

    pub fn protocol_ctx(&self) -> &ProtocolCtx {
        &self.protocol_ctx
    }

    pub fn set_protocol_ctx(&mut self, protocol_ctx: ProtocolCtx) {
        self.protocol_ctx = protocol_ctx;
    }
}

impl QueryContextBuilder {
    pub fn build(self) -> QueryContext {
        let channel = self.channel.unwrap_or_default();
        let mut extensions = self.extensions.unwrap_or_default();
        extensions
            .entry(REMOTE_QUERY_ID_EXTENSION_KEY.to_string())
            .or_insert_with(generate_remote_query_id);
        QueryContext {
            current_catalog: self
                .current_catalog
                .unwrap_or_else(|| DEFAULT_CATALOG_NAME.to_string()),
            snapshot_seqs: self.snapshot_seqs.unwrap_or_default(),
            sst_min_sequences: self.sst_min_sequences.unwrap_or_default(),
            mutable_session_data: self.mutable_session_data.unwrap_or_default(),
            mutable_query_context_data: self.mutable_query_context_data.unwrap_or_default(),
            sql_dialect: self
                .sql_dialect
                .unwrap_or_else(|| Arc::new(GreptimeDbDialect {})),
            extensions,
            query_options_snapshotted: false,
            configuration_parameter: self
                .configuration_parameter
                .unwrap_or_else(|| Arc::new(ConfigurationVariables::default())),
            channel,
            batching_enabled: self.batching_enabled.unwrap_or_default(),
            admitted_write: None,
            logical_batching_enabled: self.logical_batching_enabled.unwrap_or_default(),
            process_id: self.process_id.unwrap_or_default(),
            conn_info: self.conn_info.unwrap_or_default(),
            protocol_ctx: self.protocol_ctx.unwrap_or_default(),
        }
    }

    pub fn set_extension(mut self, key: String, value: String) -> Self {
        self.extensions
            .get_or_insert_with(HashMap::new)
            .insert(key, value);
        self
    }
}

#[derive(Debug, Clone, Default)]
pub struct ConnInfo {
    pub client_addr: Option<SocketAddr>,
    pub channel: Channel,
}

impl Display for ConnInfo {
    fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
        write!(
            f,
            "{}[{}]",
            self.channel,
            self.client_addr
                .map(|addr| addr.to_string())
                .as_deref()
                .unwrap_or("unknown client addr")
        )
    }
}

impl ConnInfo {
    pub fn new(client_addr: Option<SocketAddr>, channel: Channel) -> Self {
        Self {
            client_addr,
            channel,
        }
    }
}

/// Returns the SQL dialect for the given query channel.
pub fn dialect_for_channel(channel: Channel) -> Arc<dyn Dialect + Send + Sync> {
    match channel {
        Channel::Mysql => Arc::new(MySqlDialect {}),
        Channel::Postgres => Arc::new(PostgreSqlDialect {}),
        _ => Arc::new(GenericDialect {}),
    }
}

#[derive(Default, Debug)]
pub struct ConfigurationVariables {
    postgres_bytea_output: ArcSwap<PGByteaOutputValue>,
    pg_datestyle_format: ArcSwap<(PGDateTimeStyle, PGDateOrder)>,
    pg_intervalstyle_format: ArcSwap<PGIntervalStyle>,
    query_options: RwLock<HashMap<String, String>>,
}

impl Clone for ConfigurationVariables {
    fn clone(&self) -> Self {
        Self {
            postgres_bytea_output: ArcSwap::new(self.postgres_bytea_output.load().clone()),
            pg_datestyle_format: ArcSwap::new(self.pg_datestyle_format.load().clone()),
            pg_intervalstyle_format: ArcSwap::new(self.pg_intervalstyle_format.load().clone()),
            query_options: RwLock::new(self.query_options.read().unwrap().clone()),
        }
    }
}

impl ConfigurationVariables {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn set_postgres_bytea_output(&self, value: PGByteaOutputValue) {
        let _ = self.postgres_bytea_output.swap(Arc::new(value));
    }

    pub fn postgres_bytea_output(&self) -> Arc<PGByteaOutputValue> {
        self.postgres_bytea_output.load().clone()
    }

    pub fn pg_datetime_style(&self) -> Arc<(PGDateTimeStyle, PGDateOrder)> {
        self.pg_datestyle_format.load().clone()
    }

    pub fn set_pg_datetime_style(&self, style: PGDateTimeStyle, order: PGDateOrder) {
        self.pg_datestyle_format.swap(Arc::new((style, order)));
    }

    pub fn pg_intervalstyle_format(&self) -> Arc<PGIntervalStyle> {
        self.pg_intervalstyle_format.load().clone()
    }

    pub fn set_pg_intervalstyle_format(&self, value: PGIntervalStyle) {
        self.pg_intervalstyle_format.swap(Arc::new(value));
    }

    pub fn allow_query_fallback(&self) -> bool {
        self.query_options().get("query.allow_query_fallback") == Some(&"true".to_string())
    }

    pub fn set_allow_query_fallback(&self, allow: bool) {
        self.query_options
            .write()
            .unwrap()
            .insert("query.allow_query_fallback".to_string(), allow.to_string());
    }

    /// Validates and stores one canonicalized per-session query option.
    pub fn set_query_option(
        &self,
        key: &str,
        value: &str,
    ) -> Result<(), crate::session_config::Error> {
        let (canonical, normalized) = crate::query_options::parse_query_option(
            key,
            value,
            crate::query_options::MAX_PUBLIC_PARALLELISM,
        )?
        .ok_or_else(|| crate::session_config::Error::InvalidConfigValue {
            name: key.to_string(),
            value: value.to_string(),
            hint: "Not a supported query option".to_string(),
            location: snafu::Location::new(file!(), line!(), column!()),
        })?;
        self.query_options
            .write()
            .unwrap()
            .insert(canonical, normalized);
        Ok(())
    }

    /// Returns the session's canonical query option overrides.
    pub fn query_options(&self) -> HashMap<String, String> {
        self.query_options.read().unwrap().clone()
    }
}

#[cfg(test)]
mod test {
    use std::collections::HashMap;

    use common_catalog::consts::DEFAULT_CATALOG_NAME;

    use crate::Session;
    use crate::context::{Channel, *};

    #[test]
    fn test_query_parallelism_wire_accepts_legacy_value() {
        let mut context = QueryContext::with(DEFAULT_CATALOG_NAME, "public");
        context.set_extension("query_parallelism", "2048");

        assert_eq!(
            context
                .effective_query_options()
                .unwrap()
                .get("query.parallelism"),
            Some(&"2048".to_string())
        );
    }

    #[test]
    fn test_set_query_parallelism_public_limit() {
        let context = QueryContext::with(DEFAULT_CATALOG_NAME, "public");
        assert!(
            context
                .configuration_parameter()
                .set_query_option("query.parallelism", "1025")
                .is_err()
        );
        assert!(
            context
                .configuration_parameter()
                .set_query_option("query.parallelism", "1024")
                .is_ok()
        );
    }

    #[test]
    fn test_session() {
        let session = Session::new(
            Some("127.0.0.1:9000".parse().unwrap()),
            Channel::Mysql,
            Default::default(),
            100,
        );
        // test user_info
        assert_eq!(session.user_info().username(), "greptime");

        // test channel
        assert_eq!(session.conn_info().channel, Channel::Mysql);
        let client_addr = session.conn_info().client_addr.as_ref().unwrap();
        assert_eq!(client_addr.ip().to_string(), "127.0.0.1");
        assert_eq!(client_addr.port(), 9000);

        assert_eq!("mysql[127.0.0.1:9000]", session.conn_info().to_string());
        assert_eq!(100, session.process_id());

        let query_ctx = session.new_query_context();
        assert!(query_ctx.remote_query_id().is_some());
    }

    #[test]
    fn test_context_db_string() {
        let context = QueryContext::with("a0b1c2d3", "test");
        assert_eq!("a0b1c2d3-test", context.get_db_string());

        let context = QueryContext::with(DEFAULT_CATALOG_NAME, "test");
        assert_eq!("test", context.get_db_string());
    }

    #[test]
    fn test_fork_has_independent_mutable_session_data() {
        let context = QueryContext::with(DEFAULT_CATALOG_NAME, "public");
        let fork = context.fork();

        fork.set_current_schema("private");

        assert_eq!(context.current_schema(), "public");
        assert_eq!(fork.current_schema(), "private");
    }

    #[test]
    fn test_skip_wal_default_builder_and_fork() {
        let default_context = QueryContext::with(DEFAULT_CATALOG_NAME, "public");
        assert!(!default_context.skip_wal());
        assert!(!QueryContextBuilder::default().build().skip_wal());
        let context = QueryContextBuilder::default().skip_wal(true).build();
        assert!(context.skip_wal());
        let fork = context.fork();
        assert!(fork.skip_wal());
        fork.set_skip_wal(false);
        assert!(context.skip_wal());
        assert!(!fork.skip_wal());
        context.set_skip_wal(false);
        fork.set_skip_wal(true);
        assert!(!context.skip_wal());
        assert!(fork.skip_wal());
    }

    #[test]
    fn test_write_admission_is_local_and_database_scoped() {
        let ctx = QueryContext::with_channel("greptime", "public", Channel::Otlp);
        let admitted = ctx.with_write_admission();
        assert_eq!(ctx.write_rows_to_admit("greptime", "public", 100), 100);
        assert_eq!(admitted.write_rows_to_admit("greptime", "public", 100), 0);
        assert_eq!(admitted.write_rows_to_admit("greptime", "other", 100), 100);
        assert_eq!(admitted.write_rows_to_admit("other", "public", 100), 100);
        assert_eq!(admitted.channel(), Channel::Otlp);
        assert_eq!(
            admitted
                .fork()
                .write_rows_to_admit("greptime", "public", 100),
            0
        );
        let wire: api::v1::QueryContext = admitted.into();
        let restored = QueryContext::try_from(wire).unwrap();
        assert_eq!(restored.write_rows_to_admit("greptime", "public", 100), 100);
    }

    #[test]
    fn test_skip_wal_is_not_serialized_in_query_context() {
        let context = QueryContextBuilder::default().skip_wal(true).build();
        let api_context: api::v1::QueryContext = context.into();
        assert!(
            !api_context
                .extensions
                .contains_key(crate::hints::INSERT_SKIP_WAL_HINT)
        );
        let restored: QueryContext = api_context.try_into().unwrap();
        assert!(!restored.skip_wal());
    }

    #[test]
    fn test_api_query_context_roundtrip_with_sequences() {
        let api_ctx = api::v1::QueryContext {
            current_catalog: "c1".to_string(),
            current_schema: "s1".to_string(),
            timezone: "UTC".to_string(),
            extensions: HashMap::from([("flow.return_region_seq".to_string(), "true".to_string())]),
            channel: Channel::Internal as u32,
            snapshot_seqs: Some(api::v1::SnapshotSequences {
                snapshot_seqs: HashMap::from([(1, 100)]),
                sst_min_sequences: HashMap::from([(1, 90)]),
            }),
            explain: None,
        };

        let session_ctx: QueryContext = api_ctx.clone().try_into().unwrap();
        let roundtrip_api: api::v1::QueryContext = session_ctx.into();

        assert_eq!(roundtrip_api.current_catalog, api_ctx.current_catalog);
        assert_eq!(roundtrip_api.current_schema, api_ctx.current_schema);
        assert_eq!(roundtrip_api.timezone, api_ctx.timezone);
        assert_eq!(
            roundtrip_api.extensions.get("flow.return_region_seq"),
            Some(&"true".to_string())
        );
        assert!(
            roundtrip_api
                .extensions
                .contains_key(REMOTE_QUERY_ID_EXTENSION_KEY)
        );
        assert_eq!(roundtrip_api.channel, api_ctx.channel);
        assert_eq!(roundtrip_api.snapshot_seqs, api_ctx.snapshot_seqs);
    }

    #[test]
    fn test_query_context_remote_query_id_round_trip() {
        let query_id = "0195f4fd-c503-7c54-8b8f-7dfb8f6f9c4a";
        let ctx = QueryContextBuilder::default()
            .current_catalog(DEFAULT_CATALOG_NAME.to_string())
            .current_schema("public".to_string())
            .set_extension(
                REMOTE_QUERY_ID_EXTENSION_KEY.to_string(),
                query_id.to_string(),
            )
            .build();

        assert_eq!(ctx.remote_query_id(), Some(query_id));
        assert_eq!(ctx.remote_query_id_value().unwrap().to_string(), query_id);

        let proto: api::v1::QueryContext = (&ctx).into();
        let restored = QueryContext::try_from(proto).unwrap();
        assert_eq!(restored.remote_query_id(), Some(query_id));
        assert_eq!(
            restored.remote_query_id_value().unwrap().to_string(),
            query_id
        );
    }

    #[test]
    fn test_query_context_read_preference_wire_values() {
        let wire = |value: Option<&str>| api::v1::QueryContext {
            current_catalog: DEFAULT_CATALOG_NAME.to_string(),
            current_schema: DEFAULT_SCHEMA_NAME.to_string(),
            timezone: "UTC".to_string(),
            extensions: value
                .map(|value| {
                    HashMap::from([(READ_PREFERENCE_EXTENSION_KEY.to_string(), value.to_string())])
                })
                .unwrap_or_default(),
            channel: Channel::Internal as u32,
            snapshot_seqs: None,
            explain: None,
        };

        let header = RegionRequestHeader::default();
        let header_context = QueryContext::try_from(&header).unwrap();
        assert_eq!(header_context.read_preference(), ReadPreference::Leader);

        for value in [None, Some("leader"), Some("LEADER")] {
            let ctx = QueryContext::try_from(wire(value)).unwrap();
            assert_eq!(ctx.read_preference(), ReadPreference::Leader);
            assert!(!ctx.extensions().contains_key(READ_PREFERENCE_EXTENSION_KEY));
        }
        for value in ["", "unknown"] {
            let error = QueryContext::try_from(wire(Some(value))).unwrap_err();
            assert!(matches!(
                error,
                crate::session_config::Error::InvalidConfigValue {
                    name,
                    value: actual,
                    ..
                } if name == "read_preference" && actual == value
            ));
        }
    }

    #[test]
    fn test_legacy_query_context_wire_defaults_to_leader() {
        use prost::Message;

        let legacy = api::v1::QueryContext::decode(
            include_bytes!(
                "../../../tests/compatibility/wire/read_preference/legacy_query_context.pb"
            )
            .as_slice(),
        )
        .unwrap();
        assert_eq!(legacy.current_catalog, "c1");
        assert_eq!(legacy.current_schema, "s1");
        assert_eq!(legacy.timezone, "UTC");
        assert_eq!(legacy.channel, Channel::Internal as u32);
        assert_eq!(
            legacy
                .extensions
                .get("flow.return_region_seq")
                .map(String::as_str),
            Some("true")
        );
        assert!(
            !legacy
                .extensions
                .contains_key(READ_PREFERENCE_EXTENSION_KEY)
        );

        let restored = QueryContext::try_from(legacy).unwrap();
        assert_eq!(restored.read_preference(), ReadPreference::Leader);
        assert_eq!(restored.current_catalog(), "c1");
        assert_eq!(restored.current_schema(), "s1");
        assert_eq!(restored.timezone().to_string(), "UTC");
        assert_eq!(restored.channel(), Channel::Internal);
        assert_eq!(restored.extension("flow.return_region_seq"), Some("true"));

        let outbound: api::v1::QueryContext = restored.into();
        let roundtrip = api::v1::QueryContext::decode(outbound.encode_to_vec().as_slice()).unwrap();
        assert_eq!(roundtrip.current_catalog, "c1");
        assert_eq!(roundtrip.current_schema, "s1");
        assert_eq!(roundtrip.timezone, "UTC");
        assert_eq!(roundtrip.channel, Channel::Internal as u32);
        assert_eq!(
            roundtrip
                .extensions
                .get("flow.return_region_seq")
                .map(String::as_str),
            Some("true")
        );
        assert!(
            !roundtrip
                .extensions
                .contains_key(READ_PREFERENCE_EXTENSION_KEY)
        );
    }

    #[test]
    fn test_outbound_read_preference_clears_stale_extension() {
        let context = QueryContextBuilder::default()
            .set_extension(
                READ_PREFERENCE_EXTENSION_KEY.to_string(),
                "stale".to_string(),
            )
            .set_extension("unrelated".to_string(), "preserved".to_string())
            .build();
        let wire: api::v1::QueryContext = context.into();
        assert!(!wire.extensions.contains_key(READ_PREFERENCE_EXTENSION_KEY));
        assert_eq!(
            wire.extensions.get("unrelated").map(String::as_str),
            Some("preserved")
        );
    }

    #[test]
    fn test_live_analyze_metrics_requires_matching_remote_query_id() {
        let mut ctx = QueryContext::arc().as_ref().clone();
        assert!(!ctx.live_analyze_metrics_enabled());

        ctx.enable_live_analyze_metrics();
        assert!(ctx.live_analyze_metrics_enabled());

        ctx.set_extension(LIVE_ANALYZE_METRICS_EXTENSION_KEY, "true");
        assert!(!ctx.live_analyze_metrics_enabled());

        ctx.set_extension(LIVE_ANALYZE_METRICS_EXTENSION_KEY, "another-query-id");
        assert!(!ctx.live_analyze_metrics_enabled());
    }
    #[test]
    fn test_batching_selection_is_local_only() {
        let mut ctx = QueryContextBuilder::default().build();
        assert!(!ctx.batching_enabled());
        assert!(!ctx.logical_batching_enabled());
        ctx.set_logical_batching_enabled(true);
        assert!(ctx.clone().logical_batching_enabled());
        assert!(ctx.fork().logical_batching_enabled());
        ctx.set_batching_enabled(true);
        assert!(ctx.clone().batching_enabled());
        assert!(ctx.fork().batching_enabled());
        let wire: api::v1::QueryContext = ctx.into();
        let restored = QueryContext::try_from(wire).unwrap();
        assert!(!restored.batching_enabled());
        assert!(!restored.logical_batching_enabled());
        let ctx = QueryContextBuilder::default()
            .set_extension("batching_enabled".to_string(), "true".to_string())
            .build();
        assert!(!ctx.batching_enabled());
    }
}